Sidney C. Smith, Jr., MD

Significant elevation of hepatic enzymes may be seen in approximately 10 to 15% of patients blood pressure young age quality 50 mg metoprolol. Viral resistance to stavudine may develop blood pressure chart for excel order metoprolol 50 mg visa, and cross-resistance to zidovudine and didanosine may occur heart attack 38 years old buy cheap metoprolol. Stavudine should be used with caution in patients at risk for hepatic disease and those who have had pancreatitis blood pressure scale buy metoprolol 50 mg low cost. Although hydroxyurea enhances the antiviral activity of stavudine and didanosine blood pressure medication depression side effects metoprolol 100 mg order on-line, combination therapy that includes stavudine and didanosine, with or without hydroxyurea, increases the risk of pancreatitis. Combinations of stavudine and didanosine should not be given to pregnant women because of the increased risk of metabolic acidosis. Zidovudine inhibits the phosphorylation of stavudine; thus, this combination should be avoided. Abdominal pain, nausea, vomiting, anorexia, and dose-related peripheral neuropathy may occur. Pancreatitis occurs rarely, as do hyperuricemia, bone marrow suppression, retinal depigmentation, and optical neuritis. Resistance to didanosine appears to result from mutations different from those responsible for zidovudine resistance. Didanosine should be used with great caution in individuals who have a history of pancreatitis. Didanosine tablets contain phenylalanine and should not be taken by phenylketonurics. Buffering agents that are compounded with didanosine to counteract its degradation by gastric acid may interfere with the absorption of other drugs that require acidity. The use of zalcitabine with didanosine is not recommended because that combination carries an additive risk of peripheral neuropathy. Stavudine should not be given with didanosine to pregnant women because of the increased risk of metabolic acidosis. Combination products contain lamivudine with either zidovudine (Combivir) or zidovudine and abacavir (Trizivir). The use of low-dose lamivudine in the treatment of chronic hepatitis B is described in Chapter 50. Gastrointestinal complaints are common with lamivudine­ zidovudine therapy but are probably mainly due to the zidovudine component. Cross-resistance to zalcitabine, didanosine, and abacavir can occur simultaneously. Lamivudine is associated with an increased risk of pancreatitis in children and should be used with great caution in children who have had pancreatitis or are at high risk for it. It may be less effective than the other nucleoside inhibitors and is used less frequently. Stomatitis, esophageal ulceration, hepatotoxicity, rash, and pancreatitis may occur. Zalcitabine should be used with caution in individuals with a history of pancreatitis, liver disease, or alcohol abuse. Zalcitabine should not be used in combination with didanosine, lamivudine, or stavudine. Nucleotide Reverse Transcriptase Inhibitors Tenofovir Tenofovir disoproxil fumarate (Viread) is a prodrug of tenofovir, a phosphorylated adenosine nucleoside analogue, and is the only available agent of its class. Its coadministration with didanosine results in increased plasma levels of didanosine that can produce toxicity. It is used as part of a multidrug regimen and is available in a fixed-dose combination with zidovudine and lamivudine (Trizivir). Abacavir is associated with side effects such as anorexia, nausea, vomiting, malaise, headache, and insomnia. A potentially fatal hypersensitivity reaction develops in approximately 5% of patients, usually early in the course of treatment. Fever and rash are the most common symptoms of this reaction; malaise, respiratory symptoms, and gastrointestinal complaints may also occur. Resistance to abacavir may be associated with resistance to zidovudine, didanosine, and lamivudine. Abacavir undergoes extensive hepatic metabolism; therefore, patients with liver disease should be monitored closely if this drug is given. Efavirenz should be avoided during pregnancy because primate studies have shown it to be teratogenic at doses near therapeutic levels. Average values for fed adult patients, following a multiple oral dosing Unchanged drug Elimination half-life increases with dose; this value is for dose of 400 mg tid. It should not be given with cisapride, ergot alkaloids, midazolam, or triazolam because of the potential for lifethreatening reactions. Efavirenz has the potential to decrease blood levels of methadone, rifabutin, ketoconazole, and itraconazole. It may inhibit the metabolism of drugs such as alosetron, diazepam, ethinyl estradiol, imipramine, losartan, omeprazole, warfarin, tolbutamide, and topiramate. Saquinavir should not be used as the sole protease inhibitor in a regimen containing efavirenz. Delavirdine should not be used in combination with alprazolam, cisapride, ergot alkaloids, midazolam, or triazolam because of the potential for serious adverse reactions. This enzyme, which is required for the production of a mature infectious virus, cleaves the gag-pol polyprotein into structural proteins and active enzymes. Although different protease mutations tend to be associated with resistance to individual drugs, resistance to one protease inhibitor is often associated with a less than optimal response to other agents of this class. Indinavir, ritonavir, and lopinavir require more mutations to lose their effectiveness than do the other protease inhibitors. Drug-induced hyperglycemia and insulin resistance may precipitate the onset of diabetes mellitus or worsen existing cases. Fat redistribution is common and can manifest as central fat accumulation, peripheral wasting, buffalo hump at the base of the neck, breast enlargement, and/or lipomas. These drugs should be used with caution in patients with diabetes, lipid disorders, and hepatic disease. Many drugs interact with protease inhibitors by inhibiting or inducing their metabolism; similarly, protease inhibitors inhibit or induce the metabolism of numerous drugs (Table 51. During the first 12 weeks of treatment, patients must be closely monitored for the development of potentially fatal hepatic toxicity. Although these toxicities are rare, common side effects include mild to moderate rash, fever, nausea, fatigue, headache, and elevated liver enzymes. Nevirapine may decrease the effectiveness of ethinyl estradiol­based contraceptives and can lower plasma concentrations of methadone. Rash accompanied by pruritus is the most frequent adverse effect of this agent; however, it usually resolves within several weeks of treatment. Headache, nausea, vomiting, diarrhea, fatigue, and elevated hepatic enzymes also may be associated with delavirdine administration. Fortovase, a soft gel preparation of saquinavir, has largely replaced saquinavir mesylate capsules (Invirase) because it has improved bioavailability. Saquinavir is usually well tolerated and most frequently produces mild gastrointestinal side effects. It is mainly used in low doses to increase blood levels of other protease inhibitors and to extend their dosing interval. This list is not all-inclusive; it is important to check individual drug interactions when prescribing protease inhibitors. It is available only via registered prescribers to patients who meet specific eligibility conditions. For example, ritonavir should not be used in conjunction with amiodarone, bepridil, flecainide, propafenone, quinidine, or pimozide. Additional side effects include asymptomatic hyperbilirubinemia, alopecia, ingrown toenails, and paronychia. Nelfinavir Nelfinavir (Viracept) is probably the most commonly used protease inhibitor because of its low incidence of serious adverse effects. Its most common side effects are diarrhea and flatulence; these may resolve with continued use. In addition to the drugs contraindicated for use with all protease inhibitors, amiodarone, rifampin, and quinidine are contraindicated in patients taking nelfinavir. It produces the side effects common to all protease inhibitors and also may produce nephrolithiasis, urolithiasis, and possibly renal insufficiency or renal failure. This problem occurs more fre- Amprenavir Amprenavir (Agenerase) is administered twice daily, providing the patient with an advantage over other protease inhibitors that must be taken more frequently. Common side effects of am- 51 Therapy of Human Immunodeficiency Virus 593 prenavir include nausea, vomiting, diarrhea, and perioral paraesthesias. Rash occurs in approximately 20 to 30% of patients and can be mild or severe (StevensJohnson syndrome). Amprenavir oral solution contains large amounts of the excipient propylene glycol and should not be given to children under age 4 because it can produce hyperosmolality, lactic acidosis, seizures, and/or respiratory depression. Pregnant women should not take amprenavir oral solution, as fetal toxicity may result. Amprenavir is a sulfonamide and should be used with caution in patients with sulfonamide allergy. Amprenavir oral solution and capsules contain high levels of vitamin E; therefore, patients are advised not to take supplemental vitamin E. In addition to the drugs contraindicated for use with all protease inhibitors, amprenavir should not be given with pimozide or rifampin. The teratogenic risk associated with administration of antiretroviral drugs during the first trimester of pregnancy is not clear. If a woman decides to discontinue antiretroviral therapy during pregnancy, all drugs should be stopped and reintroduced simultaneously to avoid the development of resistance. Pregnant women may be particularly susceptible to hyperglycemia caused by protease inhibitors. The risk of this type of vertical transmission ranges from 5 to 20%; longer durations of breast-feeding, mastitis, and abscesses are associated with increased risk. The World Health Organization recommends that under these circumstances exclusive breast-feeding should be maintained for the first months of life and discontinued when replacement feeding is acceptable, feasible, affordable, sustainable, and safe. Lopinavir­Ritonavir Lopinavir is available in the United States only as a fixed-dose combination with ritonavir (Kaletra). Side effects, which are generally mild, include diarrhea, nausea, asthenia, and headache. In addition to the drugs contraindicated for all protease inhibitors, flecainide, propafenone, pimozide, and rifampin should not be given with lopinavir­ritonavir combination therapy. These factors put her at high risk for drug-induced (A) Lactic acidosis, hepatomegaly, and hepatic steatosis (B) Peripheral neuropathy (C) Stevens-Johnson syndrome (D) Hyperuricemia (E) Hypersensitivity reaction 3. To help him fall asleep at night, he took a normal dose of diazepam (10 mg before bed), which he got from a friend. The most likely reason for this is that (A) Efavirenz inhibits the hepatic metabolism of diazepam (B) Efavirenz competes with diazepam for renal elimination (C) Lamivudine potentiates the depressant activity of diazepam (D) Zidovudine induces the metabolism of diazepam (E) Lamivudine stimulates conversion of diazepam to its active form 4. Diazepam is almost completely converted to inactive metabolites; therefore, renal elimination is not much of a concern. Lamivudine may produce fatigue as a side effect but does not potentiate the depressant activity of diazepam. Zidovudine does not induce cytochrome P450 activity, and diazepam does not have to be converted to an active form for sedative activity. This combination includes a low dose of ritonavir that is not likely to cause serious side effects but instead inhibits lopinavir metabolism. Lopinavir is almost completely eliminated by metabolism to inactive metabolites; little is eliminated unchanged by the kidney. Lamivudine, a cytosine analogue, is a nucleoside reverse transcriptase inhibitor that acts as a competitive inhibitor of reverse transcriptase. Characterization of chemokine receptor utilization of viruses in the latent reservoir for human immunodeficiency virus type 1. R returned to his physician with a severe herpes outbreak on one side of his face. Superficial fungal infections involve cutaneous surfaces, such as the skin, nails, and hair, and mucous membrane surfaces, such as the oropharynx and vagina. A growing number of topical and systemic agents are available for the treatment of these infections. Deep- seated or disseminated fungal infections caused by dimorphic fungi, the yeasts Cryptococcus neoformans, and various Candida spp. Polyene antifungal drugs bind to the fungal cell membrane component ergosterol, leading to increased fungal cell membrane permeability and the loss of intracellular constituents. Amphotericin has a lesser affinity for the mammalian cell membrane component cholesterol, but this interaction does account for most adverse toxic effects associated with this drug. Clinical Uses Amphotericin B is most commonly used to treat serious disseminated yeast and dimorphic fungal infections in immunocompromised hospitalized patients. As additional experience has been gained in the treatment of fungal infections with the newer azoles, the use of amphotericin B has diminished; if azole drugs have equivalent efficacy, they are preferred to amphotericin B because of their reduced toxicity profile and ease of administration. For the unstable neutropenic patient with Candida albicans fungemia, amphotericin B is the drug of choice. Most forms of blastomycosis and sporotrichosis in normal hosts no longer require amphotericin B treatment. Amphotericin B remains the drug of choice in the treatment of invasive aspergillosis, locally invasive mucormycosis, and many disseminated fungal infections occurring in immunocompromised hosts (the patient population most at risk for serious fungal infections). For example, the febrile neutropenic oncology patient with persistent fever despite empirical antibacterial therapy is best treated with amphotericin B for possible Candida spp. Antifungal Spectrum Amphotericin B is used to treat systemic disseminated fungal infections caused by Candida spp.

Animal studies have shown that amantadine is teratogenic and rimantadine may be embryotoxic arteria 3d medieval worldbuilder classic proven metoprolol 12.5 mg. Individuals with congestive heart failure heart attack american order generic metoprolol pills, edema blood pressure medication raise blood sugar metoprolol 50 mg order otc, orthostatic hypotension prehypertension journal purchase metoprolol 50 mg with mastercard, seizure disorders pulse pressure calculator order metoprolol 12.5 mg with mastercard, or uncontrolled psychosis should be closely monitored during therapy with amantadine. The dosage of rimantadine must be decreased in cases of renal or hepatic impairment, whereas amantadine requires dosage adjustment only when renal impairment is present. Individuals over age 65 require half the dose of either drug given to younger adults. Several drug interactions involving amantadine and rimantadine are clinically significant. Thiazide­triamterene, trimethoprim­sulfamethoxazole, quinine, and quinidine increase plasma amantadine levels. Cimetidine decreases rimantadine clearance, and aspirin and acetaminophen decrease rimantadine plasma levels. Absorption, Metabolism, and Excretion Orally administered oseltamivir phosphate is rapidly absorbed and converted by hepatic esterases to oseltamivir carboxylate. Approximately 80% of an oral dose reaches the systemic circulation as oseltamivir carboxylate, with peak plasma concentrations achieved within 2. Elimination of the parent drug and its active metabolite occurs primarily by active tubular secretion and glomerular filtration. Clinical Uses Oseltamivir is approved for the treatment of uncomplicated acute influenza in patients aged 1 year and older. Oseltamivir is also indicated for the prophylaxis of influenza in individuals aged 13 and older. Oseltamivir can be used as postexposure prophylaxis in household contacts of infected patients, with infection rates of treated patients around 10% of placebo control levels. Following oral inhalation, zanamivir has a bioavailability of 12 to 17%, with peak plasma concentrations being reached within 1. It is rapidly eliminated by the kidneys without significant metabolism and has a plasma elimination half-life of 2. Clinical Uses Zanamivir is indicated for treatment of uncomplicated acute influenza A and B virus in patients aged 7 and older. Adverse Effects, Contraindications, and Drug Interactions the most frequently reported adverse effects of oseltamivir are nausea and vomiting. These events are usually mild to moderate, occur during the first 1 to 2 days of treatment, and can be lessened by taking the drug with food. Its efficacy in patients with chronic cardiac or respiratory disease has not been established. In clinical trials, no difference in the incidence of complications was seen between treatment and control groups. The efficacy of oseltamivir has not been demonstrated in immunocompromised patients, patients who begin treatment after 40 hours of symptoms, or patients given repeated prophylactic courses of therapy. Oseltamivir and its carboxylate metabolite do not interact with the cytochrome P450 system. Oseltamivir does not interfere with antibody production in response to the influenza vaccine. Adverse Effects, Contraindications, and Drug Interactions Zanamivir is generally well tolerated. Bronchospasm and impaired lung function have been reported in some patients taking this medication, but many of these individuals had serious underlying pulmonary disease. Zanamivir should be discontinued if an individual develops bronchospasm or breathing difficulties; treatment and hospitalization may be required. Zanamivir is contraindicated in individuals with severe or decompensated chronic obstructive lung disease or asthma because it has not been shown to be effective in these individuals and can cause serious adverse pulmonary reactions. Individuals with mild to moderate asthma may have a decline in lung function when taking zanamivir. The safety and efficacy of this medication have not been determined in individuals with severe renal insufficiency. Zanamivir Zanamivir (Relenza) is a neuraminidase inhibitor with activity against influenza A and B strains. Like oseltamivir, zanamivir is a reversible competitive antagonist of viral neuraminidase. It inhibits the release of progeny virus, causes viral aggregation at the cell surface, and impairs viral movement through respiratory secretions. Resistant variants with hemagglutinin and/or neuraminidase mutations have been produced in vivo; however, clinical resistance to zanamivir is quite rare at present. Absorption, Metabolism, and Excretion Zanamivir has a bioavailability of less than 5% when absorbed through the gastrointestinal tract. It is administered using a breath-actuated inhaler device (Diskhaler) Immune Globulin Immune globulin (-globulin, immunoglobulin [Ig] G) is a fraction obtained from the plasma of normal individuals and is rich in antibodies found in whole blood. It is believed to inhibit viral penetration of host cells, opsonize viral particles, activate complement, and stimulate cell-mediated immunity. Vaccinations should be deferred until several months after the administration of -globulin because the antibodies contained in this preparation may interfere with the development of the host immune response. Individuals who were vaccinated shortly before receiving immune globulin may require revaccination at a later time. Intramuscular or intravenous injections are given during the early infectious stage to alleviate the progression of certain viral disorders. Protection lasts for 2 to 3 weeks after a single injection, although for prolonged infections, injections can be repeated every 2 to 3 weeks. These endogenous proteins exert potent antiviral, immunoregulatory, and antiproliferative effects and are classified according to the cell type from which they were initially derived. Interferon- and interferon- exert the most potent antiviral effects; interferon- is antiviral and strongly immunomodulatory. Interferons also induce the production of inflammatory cytokines and biological oxidants that further enhance the host immune response. Viral families differ with respect to the step or steps at which interferons exert their effects. A pooled heterogeneous human immune globulin solution (BayGam, Gamimmune, others) can be used to lessen the likelihood of measles, varicella, or rubella infection in individuals exposed to these viruses. Immune globulin also can be used as an adjunctive form of therapy with other therapeutic approaches. Adverse Effects, Contraindications, and Drug Interactions Hypersensitivity reactions. The likelihood of anaphylactoid reaction increases following repeated dosing and for certain preparations, intravenous administration. Immune globulins can also cause urticaria, angioedema, fever, and injection site reactions. High doses of immune globulins have been associated with rare cases of aseptic meningitis syndrome. A possibility of infection by blood-borne pathogens exists with immune globulin and other human blood products. Although preparations are screened for contamination and viral inactivation processes are used, the risk of transmission of new or undetected pathogens cannot be eliminated. Treatment with immune globulin can interfere with the response to live virus vaccines. The various preparations may be administered subcutaneously, intramuscularly, intravenously, or intralesionally. Natural or recombinant interferons typically achieve peak plasma levels within 4 to 8 hours of subcutaneous 50 Antiviral Drugs 579 or intramuscular injection and are undetectable in the bloodstream within 16 to 36 hours. Maximal plasma concentrations of pegylated interferons are reached 15 to 44 hours after subcutaneous or intramuscular injection and are sustained for much longer than nonpegylated preparations (48 to 72 hours). Interferons are eliminated from the bloodstream by a combination of cellular uptake and catabolism in the kidney and liver. A combination of interferon- -2b and ribavirin (Rebetron) is used for the treatment of chronic hepatitis C. Interferon- -n3 (Alferon N) is a solution of purified natural human interferon- proteins approved for the treatment of condylomata acuminata by intralesional injection. Interferon alfacon-1 (Infergen) is a recombinant interferon constructed from the sequences of several naturally occurring interferon- subtypes. This recombinant protein contains the most frequently observed amino acid in each position of the sequence and exhibits in vitro specific activity at least 5 times higher than that of interferon -2a or -2b. Interferon -1a (Avonex) and interferon -1b (Betaseron) are used in the treatment of multiple sclerosis. Interferon -1b (Actimmune) is used to prevent and diminish the severity of infections associated with chronic granulomatous disease and for delaying the progression of severe, malignant osteopetrosis. Adverse Effects, Contraindications, and Drug Interactions Flulike symptoms, including fever, chills, weakness, fatigue, myalgia, and arthralgia, are the most common side effects of interferon therapy. These symptoms occur in more than 50% of patients given injections of interferons either intravenously, intramuscularly, or subcutaneously. Intralesional injection may produce milder flulike symptoms with somewhat less frequency. Suicidal behavior, although rare, can arise in depressed patients; therefore, these individuals should be closely monitored. Myelosuppression occurs frequently and may be dose limiting; potentially fatal aplastic anemia is rare. Gastrointestinal symptoms such as nausea, vomiting, diarrhea, and anorexia are common; however, ulcerative colitis, pancreatitis, hyperglycemia, and diabetes mellitus are rare. Elevation of hepatic enzymes can occur but rarely necessitate discontinuation of treatment. Injection site reaction is common, as is alopecia, for certain interferon preparations. Infrequent reactions to interferon therapy include proteinuria, renal toxicity, autoimmune disease, thyroid disease, ophthalmic toxicity, pulmonary dysfunction (pulmonary infiltrates, pneumonitis, and pneumonia), and cardiovascular effects (tachycardia, arrhythmia, hypotension, cardiomyopathy, and myocardial infarction). Rarely, the body may develop antibodies against interferons that inhibit their effectiveness. Interferons should be used with caution in persons who have myelosuppression or who are taking myelosuppressive drugs. Preparations containing benzyl alcohol are associated with neurotoxicity, organ failure, and death in neonates and infants and therefore are contraindicated in this population. Interferons should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Interferons reduce the activity of hepatic cytochrome P450 enzymes and decrease the clearance of drugs such as theophylline. Their effects may be additive with other drugs that have neurotoxic, hematotoxic or cardiotoxic activity. Following absorption, host cell enzymes convert ribavirin to its monophosphate, diphosphate, and triphosphate forms. Absorption, Metabolism, and Excretion Ribavirin can be administered as an aerosol using a small-particle aerosol generator. When administered by this route, the drug has only minimal systemic absorption, with drug concentrations in respiratory tract secretions approximately 100 times as high as those found in plasma. It is also metabolized in the liver to a triazole carboxylic acid metabolite that is eliminated in the urine along with the parent compound. Intravenous ribavirin may be useful in the therapy of Hantaan virus infection, Crimean or Congo virus hemorrhagic fever, Lassa fever, and severe adenovirus infection. When given via these routes, ribavirin can produce hemolytic anemia that is reversible following dosage reduction or cessation of therapy. When given in combination with interferon-, ribavirin increases the incidence of many of its side effects, such as fatigue, nausea, insomnia, depression, and anemia, and may cause fatal or nonfatal pancreatitis. Ribavirin is mutagenic, teratogenic, and embryotoxic in animals at doses below the therapeutic level in humans. It is contraindicated in pregnant women and in the male partners of pregnant women. Women of childbearing potential and male partners of these women must use two effective forms of contraception during ribavirin treatment and for 6 months post therapy. Ribavirin is contraindicated in patients with sickle cell anemia and other hemoglobinopathies because of its propensity to cause anemia. Similarly, persons with coronary disease should not use ribavirin, because anemia may cause deterioration of cardiac function. Oral ribavirin should not be given to individuals with severe renal impairment; no dosage adjustment is necessary for the inhaled formulation. In vitro, ribavirin inhibits the phosphorylation reactions that are required for activation of zidovudine and stavudine. Adverse Effects, Contraindications, and Drug Interactions Most adverse effects associated with aerosol ribavirin are local. Pulmonary function may decline if aerosol ribavirin is used in adults with chronic obstructive lung disease or asthma. Deterioration of pulmonary and cardiovascular function has also been seen in severely ill infants given this preparation. Health care workers exposed to aerosol ribavirin during its adminis- Absorption, Metabolism, and Excretion Lamivudine is rapidly absorbed from the gastrointestinal tract and has an oral bioavailability of approximately 85 to 90%. Lamivudine is mainly excreted unchanged by the kidney and has an elimination half-life of 5 to 7 hours. The safety and efficacy of lamivudine in patients with decompensated liver disease have not been established.

This is not a contra indication to clearing the cervical spine without additional imaging pulse pressure 46 metoprolol 100 mg buy fast delivery. She is stable hypertension signs and symptoms purchase discount metoprolol line, but the abdomen needs to be surgically explored and any injuries blood pressure medication bananas 12.5 mg metoprolol buy visa, if found arrhythmia ekg strips purchase metoprolol 12.5 mg with amex, repaired blood pressure chart 5 year old metoprolol 50 mg with visa. O ther imaging modalities will most likely not be helpful in this case and may only serve to delay care. Abdominal ultrasound imaging is not necessary in this case because the injury is apparent and it would only serve to further delay care. Diagnostic peritoneal lavage is most useful in the case of questionable abdominal bleeding in an unstable patient. Some trauma centers have advocated immediate reduction with closure of the defect with evisceration because many laparotomies are found to be negative for additional injury. However, recent studies have shown prompt operative in tervention to be the best management. An exception might be applied to a select few patients with only omentum evis ceration and benign abdominal findings. This patient is most likely suffer ing from anemia of chronic disease secondary to her Crohn disease. Anemia of chronic disease is most often a normocytic normochromic anemia and may result from any chronic inflammatory condition as a response to inflammatory cytokines. Decreased total iron-binding capacity and increased serum iron could be seen in iron overload conditions such as hemochromatosis. These inclusions are normally removed by the spleen and can be seen in patients with asplenia or a hypofunctioning spleen. Increased total iron-binding capacity and decreased serum iron is found in iron deficiency anemia. Large red blood cells on a peripheral smear indicate a macrocytic anemia, of which folate and vitamin B l 2 deficiency should come to mind. Women with heavy and irregular periods who are not taking iron sup plements are predisposed to becoming deficient in iron. Iron deficiency anemia is characterized by an increase in total iron binding capacity, decreased ferritin, and decreased serum iron. A history of heavy menstrual bleeding is more consistent with iron deficiency anemia. Folate deficiency will cause a macrocytic anemia and is caused by a lack of folate in the diet. Symptoms of vitamin B6 deficiency may include dermatitis, atrophic glossitis, angular cheilitis, somnolence, and neu ropathy. The differential for macrocytic anemias includes vitamin B l 2 or folate deficiency, alcoholism, rapid red cell turnover, and myelodysplastic syndrome. Her associated symptoms of vitiligo suggest an autoimmune etiology; thus, pernicious anemia is the most likely diagnosis. Pernicious anemia is caused by autoimmune atrophic gastritis in which antibodies against gastric parietal cells or intrinsic factor are produced. Serum B12 and anti-intrinsic or parietal cell antibody studies can confirm the diagnosis. Adenocarcinoma of the colon could potentially cause a macrocytic anemia if the terminal ileum was involved but Answer: C. Excessive alcohol consumption can cause a megaloblastic anemia, but elevated liver enzymes or a history of greater alcohol use would be present. This patient is present ing with a normocytic anemia from chronic hemolysis, pancytopenia, episodes of hemoglobinuria, and abdominal pain. In this disease, there is a deficiency of anchor proteins that link complement-inactivating proteins to red blood cell membranes. This in turn causes increased complement-mediated lysis of red blood cells, white blood cells, and platelets. Patients with paroxysmal nocturnal hemoglobinuria have an in creased tendency for venous thrombosis, such as Budd- Chiari syndrome and renal vein thrombosis. Unfortunately, paroxys mal nocturnal hemoglobinuria may evolve into aplastic anemia, myelodysplasia, myelofibrosis, or leukemia. Autoimmune hemolytic anemia is also characterized by hemolysis, but pancytopenia is generally not a feature. Glucose-6-phosphate dehydrogenase deficiency may present with hemolysis, but pancytopenia is not a feature. It would show a decreased platelet count, but the other findings in this patient would not be present. Disseminated intravascular coagulation is caused by an abnormal activation of the complement cascade that results in consumption of platelets, fibrin, and other coagulation factors and resulting micro thrombi throughout circulation. Laboratory studies will show increased prothrombin time, partial thromboplastin time, and bleeding time. Infection is a major cause of disseminated intravascular coagulation, especially sepsis from gram-negative organisms. Hemolytic uremic syndrome is a thrombotic microangiopathy that most often occurs in children. It is characterized by hemolytic anemia, acute kidney failure, and a low platelet count. Rebleeding at the operative site would generally not present with oozing from intravenous sites. This results in uterine prolapse into the vagina, most commonly presenting as dysuria. A tear in the diaphragm can also cause uterine prolapse but is less common and is usually accompanied by symptoms of incontinence. Endometrial hyperplasia occurs due to unopposed estrogen effects on the endometrium lining the uterus. This is a malignant germ cell tumor that has its peak incidence in infancy and early childhood; it is the most com mon testicular tumor in this age group. It is analogous to endodermal sinus tumor of the ovary and causes an increase in serum alpha-fetoprotein, which is also associated with hepatocellular carcinoma. Lymph from the lower 25% of the vagina (below the hymen) drains downward to the perineum, where it is received by the superficial inguinal lymph nodes. The upper three-quarters of the vagina, on the other hand, drains upward to the internal iliac nodes. Since the fornix lies adj acent to the cervix, it is classi fied as lying within the upper three-quarters of the vagina. Immature teratoma is usually a malignant tumor in females, as opposed to mature teratoma, which is usually benign. This is, however, reversed for males, in whom mature teratomas are more likely to be malignant. Adenomyosis is a benign extension of endometrial glands and stroma into the myometrium, most often causing uterine enlargement. The presence of bilateral cancerous lesions, espe cially in such a young woman, is highly suggestive of a germline mutation. Of those listed, a derangement of the p53 allele is most highly correlated with the development of breast cancer. The c-erb allele is a growth factor receptor gene and is upregulated in some breast cancers. The loss of an enzyme in the excision repair system has not been implicated in the pathogenesis of breast cancers. Leiomyomas, otherwise known as fibroids, are the most com mon benign tumors of the u terus. They are also commonly estrogen responsive, causing them to enlarge in a cyclic pattern. When they are severe, they may cause mass effects in the abdomen, such as bloating. Adenomyosis also commonly causes uterine enlargement, but this is usually bilateral and non-nodular. The same is true for endometrial hyperplasia, which also rarely reaches the size of leiomyomas or adenomyosis. Endometriosis can result in chocolate cysts, but these rarely reach the size needed to cause mass effects. A molar pregnancy could also result in an asymmetric abdominal mass, but in this case, the pregnancy test would have been positive. This question is a little tricky because the mother has the misconception that her child is male. The presence of ovaries in the absence of testicles, however, is definitive of the female gender. The lack of receptors for dihydrotestosterone is seen in androgen insensitivity syndrome. Antibiotic therapy can reduce normal flora in the bowel, allowing pathogenic organisms normally present in low numbers to overgrow. Patients with antibiotic induced diarrhea usually are on antibiotics for a chronic period of time. Botulinum toxin food poisoning will not cause overgrowth of Clostridium dif ficile. Mechanical obstruction of the left colon will not cause overgrowth of Clostridium dif ficile. Invasive bacteria are those that can enter host cells or penetrate mucosal surfaces, spreading from the initial site of infection. Streptococcus pyogenes produce several toxins, including C5a peptidase, which inactivates complement component C5a. Streptolysin 0 and S are also produced, which damage mammalian cells, resulting in cell lysis and release of lysosomal enzymes. Hyaluronidase is an enzyme that can degrade components of the extracellular matrix to allow bacteria easier access to host cells. For patients with recurrent cancer, using a different chemotherapeutic agent than was used initially is often favored. This is due to the fact that cancer cells can become resistant to chemotherapy drugs to which they are exposed. The physician chose to use irinotecan, an agent that inhibits topoisomerase, this time in hopes to avoid any resistance the cancer cells may have to microtubule inhibitors. Erlotinib inhibits cell proliferation by blocking the epidermal growth factor receptor. Degree of cyanosis may not correlate with degree of hypoxemia: factors that shift hemoglobin dissociation curve to the right. It res uIts from poor p&rfu sion and increased venous pres· ure and can be accentuated by polycythemia. Differential Diag1osis of Cyanosis in tile Newbom Cardiovascular Cyanotic congenital heart disease with right to left shunting Severe congestive heart failure · Myocardial disease · Significant left to right shunt resulting in severe pulmonary edema low cardiac output Central hypoventilation or apnea · Perinatal asphyxia · Intracranial hemorrhage · Seizures · Exposure to maternal sedatives · Structural brain abnormalities · Metabolic disorders · Congenital central hypoventilation syndrome Pulmonary vascular disease · Persistent pulmonary hypertension of the newborn · Pulmonary atrioventricular malformations (sometimes present in infants with hepatic disease) Anatomic upper airway abnonnalities (Pierre-Robin. Pulmonary Cyanoaia is beat sean in mucous membranes nasa, mouth, tongue) and periorally. Lung exam: breathing pattern (tachypnea, shallow, irregular), respiratory distress (grunting, retractions), auscultation for diminished breath sounds, rales, wheeze, or rhonchi a. Tachypnea without respiratory distress is a common presentation of cyanotic cardiac disease ("happy tachypnea") b. Pa01 > 200 mm Hg = cardiac lesion very unlikely and highly suggests pulmonary or neurologic disease b. Pa01 50-150 mm Hg = suggests mixing cardiac lesion without restrictive pulmonary blood flow (truncus arteriosus, tricuspid atresia) c. Pulmonary: pneumonia, pneumothorax, effusion, atelectasis, congenital diaphragmatic hernia b. Lower uturation in the leg than in the right hand suggetts right to left shunting. Broad differential diagnosis covers large range of benign and malignant conditions w~ wm:·:m ~ Moat common identified source of chest pain is musculoskeletal. Are there other symptoms associated with the chest pain, such as fever, lethargy, poor appetite, difficulty breathing, or recent illness Benign musculoskeletal pain does not have associated fever, weight loss, or other constitutional symptoms b. Difficulty breathing/wheezing or coughing is common finding with asthma or other respiratory complaints c. Fever and/or rash may occur with inflammatory conditions, myocarditis, pericarditis, pleuritis, or oncologic conditions ~fiJ·t·na:wmu Cardiac causes of chest pain are more likely to occur with exertion, end arrhythmias nrrs/ypresent with chest pain. Association with eating concerning for gastroesophageal reflux, esophagitis, or gastritis 3. Respiratory exam may reveal asymmetric decreased breath sounds, wheezing, rhonchi, or rales in the setting of underlying pulmonary disease 2. Umited evaluation is needed if physical exam is normal, family history negative, and history is not suggestive of underlying disease 2. Presentation in infants may be asymptomatic or nonspecific, including feeding problems and increased fussiness ii. Septic shock (tachycardia due to vasodilation, hypotension, and increased metabolic demand) b. Tricyclic antidepressants, antihistamines, antipsychotics, and other medications have anticholinergic effects ii. Is there sweating with feedings, color changes or cyanosis, or complaints of chest pain or palpitations May result in unconsciousness and cyanosis but requires behavioral intervention only c. J) I If apatient continuescardioto have symptoms, consider logy referral for Holter or event monitor placement. Dilated cardiomyopathy leads to syncope through arrhythmias or poor cardiac output c. Postural drop in blood pressure when moving from laying or sitting to standing, resulting in decreased cerebral perfusion ii. May be due to hypovolemia, decreased vascular tone, and associated decreased venous retum b. Ask specifically for femily history of motor vehicle accidents, drowning, or unexplained childhood death that may represent sudden cardiac death.

Although other types of phosphodiesterases are present in the corpus cavernosum arteria entupida 70 buy on line metoprolol, they do not appear to play a significant physiological role in erection heart attack 26 metoprolol 12.5 mg otc. It has a shorter onset of action and can be used in smaller doses than sildenafil hypertension glaucoma generic 50 mg metoprolol otc. Such a classification system takes into account the mode of drug action heart attack vs angina 12.5 mg metoprolol purchase with amex, the route of administration arrhythmia facts purchase metoprolol line, and the means by which target organ selectivity is achieved. A therapeutic taxonomy of treatment for erectile dysfunction: An evolutional imperative. Local injections or dermal applications were frequently required for satisfactory pharmacological actions upon the vascular smooth muscles of the penis. Compounds with relatively short duration of action were found to be less than satisfactory in maintaining penile erections. Combinations of drugs have sometimes been used to take advantage of the differing onset and duration of action of the individual compounds. Vasoactive agents that are orally effective have been available for about 20 years, but sildenafil and apomorphine (buccal) have significantly improved upon the therapeutic efficacy of orally active agents. The injection does not appear to produce any long-term side effects on penile smooth muscle. Apomorphine Apomorphine (Uprima) is a short-acting central and peripheral dopamine receptor agonist that can elicit male sexual responses. It is not orally active except for a special buccal formulation, but it can be given parenterally, usually subcutaneously. Apomorphine is rapidly cleared from the kidney because of its high lipid solubility, its large volume of distribution, and its rapid metabolism. Apomorphine stimulates penile erection in both normal men and in men who are impotent. Such rapid degradation probably accounts for its lack of significant cardiovascular side effects when administered intracavernosally. Its therapeutic success depends on its being injected intracavernosally or administered transurethrally or intraurethrally. It has a narrow range (2 to 6 mg) of effective doses for its erectogenic actions, with the higher doses being more effective in inducing erections. Androgens: Testosterone Androgen deficiency can lead to decreases in nocturnal erections and libido. Hypogonadism is associated with impotence, yet erection in response to visual stimulation is preserved in men with hypogonadism, suggesting that androgens are not essential for erection. Androgen therapy in normal men may enhance sexual behavior but is without significant effect upon erectile function. Usefulness of oral methyltestosterone is limited in men with hypogonadal impotence. Improvement following transdermal testosterone may require several months of therapy. Androgen replacement regimens for treating male hypogonadism include long-acting intramuscular injections. Transdermal patches (Testoderm, Androderm) and topical testosterone gel (Androgel) are also available. Transdermal testosterone also may improve sexual function and psychological well-being in women who have undergone oophorectomy and hysterectomy. Transdermal delivery systems can provide a more constant serum testosterone level than do intramuscular injections, but they are more expensive. Major side effects associated with papaverine therapy include priapism, corporeal fibrosis, and occasional increases in serum aminotransferases. Intracorporeal scarring may be related to the low pH of the vehicle that is necessary to solubilize papaverine. Attempts to buffer papaverine to render it more suitable for intracavernosal injection have not been entirely satisfactory, and such delivery may still lead to intracorporeal scarring. Phentolamine Human erectile tissue has a population of membrane receptors that are predominantly of the -adrenoceptor subtype. Nonselective adrenoceptor antagonists may provoke a reflex that increases both sympathetic outflow and the release of norepinephrine. Following oral administration, phentolamine has a plasma half-life of about 30 minutes and a duration of action of 2 to 4 hours. An intracavernosal injection of phentolamine results in the drug reaching maximum serum levels in about 20 to 30 minutes. It may cause orthostatic hypotension, reflex tachycardia, cardiac arrhythmias, and rarely, myocardial infarction. Other -adrenoceptor receptor antagonists include yohimbine, phenoxybenzamine, and thymoxamine. Yohimbine is an 2-adrenoceptor antagonist, and thymoxamine is a competitive and relatively selective blocking agent for 1- adrenoceptors. Phenoxybenzamine blocks both 1- and 2-adrenoreceptors, although it has a greater affinity for the 1-subtype. All three of these -receptor blocking drugs can induce penile erection, but their effects are generally less consistent and less effective than those of phentolamine. Yohimbine is only moderately effective in treating patients with organic impotence, and side effects may include postural hypotension, heart palpitations, fine tremors, and cavernosal fibrosis, especially following intracavernosal injections. Its principal pharmacological action is as a nonspecific vasodilator of smooth muscles of the arterioles and capillaries. Various vascular beds and smooth muscle respond differently to papaverine administration both in intensity and duration. Papaverine decreases the resistance to arterial inflow and increases the resistance to venous outflow. Papa- Sildenafil Sildenafil (Viagra) was developed more than 10 years ago as an antihypertensive and antianginal drug. It 64 Drugs Used in the Treatment of Erectile Dysfunction 739 proved ineffective in these applications but was shown to affect the smooth muscles of the penis. The selective inhibition of this enzyme facilitates the release of nitric oxide and smooth muscle relaxation of the corpus cavernosa. Sildenafil enhances erection by augmenting nitric oxide­mediated relaxation pathways. Sildenafil is readily absorbed after oral administration and reaches peak plasma levels after about an hour. An initial dose of 50 mg is taken about an hour prior to sexual activity to induce penile erection. It has also been used for so-called salvage therapy in men who do not respond to intracorporeal injections of other agents. More serious side effects include definite or suspected myocardial infarctions and cardiac arrest. Trazodone may cause priapism and enhance libido, and it prolongs nocturnal erections. However, it may be an option for selected patients, particularly those with performance anxiety or low libido. Injected intracavernosally it can produce penile erections, but its clinical usefulness has not been fully established. Nitroglycerin (also isosorbide nitrate) relaxes isolated strips of human corpus cavernosum. Minoxidil, an antihypertensive agent, produces arteriolar vasodilation by an unknown mechanism. In limited clinical studies, minoxidil increases penile rigidity and has been used in the long-term treatment of organic impotence. Injected intracavernosally, forskolin has been of limited use in the treatment of vasculogenic impotence. Other herbal remedies or so-called natural products purportedly can enhance male sexual activity. Natural prosexual agents of herbal origin include Epidemicum sagthatum, Tribulas terrestris, and Murira puama. Their use in folk medicine in China and other countries is likely due to their sexual stimulating properties and their aphrodisiac effects. For example, the concomitant use of sildenafil and nitroglycerin is contraindicated by cardiovascular complications. Also, the use of testosterone in the presence of androgendependent tumors may promote tumor growth. Sildenafil has other minor adverse effects, such as headache, nasal congestion, and flushing. There are no clinically significant drug interactions between sildenafil and apomorphine. However, unlike sildenafil, it exerts its action through the central nervous system. Apomorphine can produce dizziness, nausea, pallor, and hypotension, and in the presence of ethanol, it purportedly increases Other Agents Many other drugs and herbals exhibit varying degrees of potency with respect to penile erection. Some have undergone limited clinical trials, while others are associated with anecdotal reports. Such a synergy caused by ethanol and apomorphine coadministration is not unique and would likely be present with other agents that induce mild hypotension. The concomitant intake of grapefruit juice increases the concentration of many drugs. The resultant diminished first-pass metabolism and increased bioavailability can lead to increased drug levels in the blood. Administration of cimetidine, erythromycin, or ritonavir can lead to increases in serum concentrations of sildenafil, while rifampin diminishes blood levels of sildenafil. Therapy with phentolamine may result in reflex tachycardia, arrhythmias, and hypotension; the latter effect can be exacerbated by other vasodilatory drugs and by the simultaneous ingestion of ethanol. Testosterone therapy may be indicated for the treatment of erectile dysfunction in which of the following situations Although -adrenoceptor blocking agents are not approved for the treatment of erectile dysfunction, they have been shown to have some effectiveness. The only time testosterone is indicated for the treatment of erectile dysfunction is if the cause is clearly related to hypogonadism. In other situations, the adverse effects related to testosterone and its limited effectiveness preclude its use. The principal action of sildenafil is selective inhibition of the enzyme phosphodiesterase type 5. He states that he has a family history of diabetes mellitus but is not receiving any insulin or oral hypoglycemic drugs. Blood chemistries and hormone levels are as follows: total insulin (free and bound), 15 microunits/mL; T4 (thyroxine), 10 g/dL; testosterone (total), 200 ng/dL; fasting blood glucose, 210 mg/dL; dihydrotestosterone, 10 ng/dL. Based on this medical history and the hormone levels, what treatment would you initiate Whether or not there is a vasculogenic problem from the diabetes mellitus cannot be determined. The blood glucose is elevated, and a workup for diabetes may be pursued (blood insulin is normal). The hormones T4 and T3 are iodinecontaining amino acid derivatives and are unique in that they have no discrete target tissue. Every tissue in the body is affected in some way by thyroid hormones, and almost all cells appear to require constant optimal amounts for normal operation. Thyroid hormones exert a wide variety of physiological actions through genomic and nongenomic mechanisms and influence the metabolism of proteins, carbohydrates, and lipids; cell morphology; membrane transport; ion homeostasis; oxygen consumption; heat production; and so on. Relatively constant circulating concentrations of T4 and T3 are required for normal growth and development and the proper functioning of the neural, reproductive, cardiovascular, gastrointestinal, and hematopoietic systems. Unlike most other hormones, whose circulating concentrations vary widely in response to external and internal stimuli, the circulating concentrations of thyroid hormones are usually held relatively constant over time. In health, two negative feedback control systems operate to maintain circulating thyroid hormone levels. It is intrinsic to the thyroid gland and acts to ensure that an adequate supply of iodide is extracted from the blood and made available for thyroid hormone synthesis despite variations in dietary iodine intake. Worldwide, the most common thyroid disorder is hypothyroidism resulting from dietary iodine deficiency. In iodine-replete areas of the world, most thyroid disorders are the result of autoimmune disease. The symptoms manifested in hypothyroid and hyperthyroid states are largely independent of any underlying disorder of the thyroid gland itself; they are a function of the degree of hormone deficiency or excess. Selenium in the form of selenocysteine is a required component for three enzymes that remove iodide from thyroid hormones. Deiodination is the major metabolic pathway by which T4 and T3 are cleared from the system. After secretion by the thyroid gland, T4 may be deiodinated to yield either T3 or the physiologically inactive reverse T3 (3,3,5 -triiodothyronine, or rT3). Subsequent to the ingestion of iodine in various forms, I is absorbed by the small intestine and enters the blood. Two competing pathways are involved in the clearance of I from the blood: renal filtration into urine and thyroidal uptake. The renal clearance rate for I (30­50 mL/minute) varies only with the glomerular filtration rate. However, the thyroidal I clearance rate is autoregulated to maintain an absolute thyroidal I uptake rate of approximately 100 g I each day. To accomplish this, the thyroidal I clearance rate may vary (3 to 100 mL/minute) depending on the concentration of I in the blood. Thyroid follicles are hollow vesicles formed by a single layer of epithelial cells that are filled with colloid. Thyroid follicular cells also remove iodide (I) from the blood and concentrate it within the follicular lumen. Within the follicles, some of the tyrosyl residues of Tg are iodinated, and a few specific pairs of iodotyrosyl residues may be coupled to form T4 and T3. Thus, T4, T3, and iodine (in the form of iodinated tyrosyl residues) are found within the peptide structure of the Tg that is stored in the follicular lumen.

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