Clarithromycin dosing

A 41-year-old woman presented with pain and pallor in the leg and a sensation of coolness exacerbated by exercise (34). For many years she had been taking a formulation containing ergotamine 1 mg plus caffeine 100 mg, at a dose of one or two tablets daily, for both prophylaxis and treatment of migraine. For 7 days she had also taken clarithromycin (dose is not stated) for a chest infection. Her legs were cool and cyanosed, with no palpable popliteal or foot pulses and an ankle-brachial index of only 0.6 (normal >0.8). 

Clarithromycin Decreased metabolism of clarithromycin Dose adjust in renal failure... 

The comorbid conditions that can affect therapy and outcomes in patients with CAP include diabetes mellitus, COPD, congestive heart failure, and renal failure.27,28 If the patient has not received antibiotics in the past 3 months, then clarithromycin or azithromycin is the recommended first-line therapy by the IDSA. If the patient has received antibiotics in the last 3 months, then the IDSA recommends using either a respiratory fluoroquinolone alone or a combination of an oral P-lactam and an advanced macrolide/azalide (e.g., clarithromycin/azithromydn). The ATS recommends combination therapy or monotherapy with a respiratory fluoroquinolone for all patients with comorbidities. The p-lactam agents recommended include high-dose amoxicillin, high-dose amoxicillin-clavulanate, cefpodoxime, cefprozil, and cefuroxime. 

Clarithromycin 15 mg/kg per day in 2 doses (adult 250 mg twice daily) Diarrhea, vomiting, rash, abnormal taste, abdominal pain SJ Many drug interactions (inhibits cytochrome P-450 3A4) suspension cannot be refrigerated and has metallic taste same microbiologic issues as azithromycin... 

Erythromycin- sulfisoxazole 50 mg/kg per day of erythromycin component in 3 4 doses Nausea, vomiting, abdominal pain, diarrhea, rash SS Many drug interactions (like clarithromycin), contraindicated in children under 2 months increasing pneumococcal resistance... 

Clarithromycin 500 mg twice daily or 1 g once daily (XL only) 1 5 mg/kg per day in 2 doses XL tablets reported to have fewer gastrointestinal problems and taste disturbances than twice-daily preparation... 

Azithromycin and clarithromycin have shown some success for cryptosporidiosis, even in HIV-positive patients.4 However, the most promising agent is nitazoxanide, which was approved recently by the FDA for the treatment of cryptosporidiosis in children. In randomized, placebo-controlled trials, nitazoxanide has demonstrated efficacy in cryptosporidiosis in immunocompetent persons, malnourished children, and HIV/AIDS patients with CD4+ cell counts above 50 cells/mm3.39 Limited evidence suggests that patients with CD4+ cell counts of less than 50 cells/mm3 may benefit from higher doses, longer durations, or both.39... 

Oral colchicine causes dose-dependent GI adverse effects (nausea, vomiting, and diarrhea) in 50% to 80% of patients before relief of the attack. Non-GI adverse effects include neutropenia and axonal neuromyopathy, which may be worsened in patients taking other myopathic drugs (e.g., statins) or in those with renal insufficiency. Colchicine should not be used concurrently with macrolide antibiotics (especially clarithromycin) because reduced biliary excretion may lead to increased plasma colchicine levels and agranulocytosis. 

Sildenafil doses should be decreased when any potent cytochrome P450 3A4 inhibitor is used (e g., cimetidine, erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir, and saquinavir). Vardenafil doses vary accordingto which agent is used (2.5 mg q 72 h for ritonavir, 2.5 mg q 24 h for indinavir, ketoconazole 400 mg daily, and itraconazole 400 mg daily and 5 mg q 24 h for ketoconazole 200 mg daily, itraconazole200 mg daily, and erythromycin). Tadalafil doses are reduced only when it is used with the most potent cytochrome P450 3A4 inhibitors (e g., ketoconazole or ritonavir). 

Clarithromycin is a macrolide antibacterial agent that should be used with caution in patients with renal impairment. The dose should be reduced if creatinine clearance is less than 30 mL/minute and the modified-release oral preparation should be avoided in this scenario. 

A4 inhibitors - Patients receiving cytochrome P450 3A4 inhibitors, such as macrolide antibiotics (erythromycin and clarithromycin), antifungal agents (ketoconazole, itraconazole, and miconazole), or cyclosporine or vinblastine should not receive doses of tolterodine greater than 1 mg twice/day (greater than 2 mg/day for ER capsules). 

Coadministration with CYP450 inhibitors- Nhen coadministered with potent CYP3A4 inhibitors (eg, ketoconazole, itraconazole, ritonavir, nelfinavir, clarithromycin, nefazodone), do not exceed a daily dose of darifenacin 7.5 mg. 

Clarithromycin - In the presence of severe renal impairment (Ccr less than 30 mL/min) with or without coexisting hepatic impairment, decreased dosage or prolonged dosing intervals may be appropriate. 

Aprepitant (Emend) [Centrally Acting Antiemetic] Uses Pre-vents N/V assoc w/ emetogenic CA chemo (eg, cisplatin) (use in combo w/ other antiemetics) Action Substance P/neurokinin l(NKi) receptor antagonist Dose 125 mg PO day 1, 1 h before chemo, then 80 mg PO qAM days 2 3 Caution [B, /-] Contra Use w/ pimozide, Disp Caps SE Fatigue, asthenia, hiccups Interactions T Effects W/ clarithromycin, diltiazem, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, troleandomycin T effects OF alprazolam, astem-izole, cisapride, dexamethasone, methylprednisolone, midazolam, pimozide, terfe-nadine, triazolam, chemo agents, eg, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, paclitaxel, vinblastine, vincristine, vinorelbine i effects W/ paroxetine,... 

Buspirone (BuSpar) [Anxiolytic] WARNING Closely monitor for worsening depression or emergence of suicidality Uses Short-term relief of anxiety Action Antianxiety antagonizes CNS serotonin receptors Dose Initial 7.5 mg PO bid T by 5 mg q2-3d to effect usual 20-30 mg/d max 60 mg/d Contra w/ MAOI Caution [B, /-] Avoid w/ severe hepatic/renal insuff Disp Tabs SE Drowsiness, dizziness, HA, N, EPS, serotonin synd, hostility, depression Notes No abuse potential or physical/psychologic d endence Interactions T Effects W/ erythromycin, clarithromycin, itraconazole, ketoconazole, diltiazem, verapamil, grapefruit juice effects W/ carbamazepine, rifampin, phenytoin, dexamethasone, phenobarbital, fluoxetine EMS T Sedation w/ concurrent EtOH use grapefruit juice may T risk of adverse effects OD May cause dizziness, miosis, N/V symptomatic and supportive... 

Deravirdine (Rescnptor) [Antiretroviral/NNRTI] Uses HIV Infxn Action Nonnucleoside RT inhibitor Dose 400 mg PO tid Caution [C, ] CDC recommends HIV-infected mothers not to breast-feed (transmission risk) w/ renal/hepatic impair Contra Use w/ drugs dependent on CYP3A for clearance (Table VI-8) Disp Tabs SE Fat redistribution, immune reconstitution synd, HA, fatigue, rash, T transaminases, N/V/D Interactions T Effects W/ fluoxetine T effects OF benzodiazepines, cisapride, clarithromycin, dapsone, ergotamine, indinavir, lovastatin, midazolam, nifedipine, quinidine, ritonavir, simvastatin, terfena-dine, triazolam, warfarin effects W/ antacids, barbiturates, carbamazepine, cimetidine, famotidine, lansoprazole, nizatidine, phenobarbital, phenytoin, ranitidine, rifabutin, rifampin effects OF didanosine EMS Use of benzodiazepines and CCBs should be avoided may cause a widespread rash located on upper body and arms OD May cause an extension of nl SEs symptomatic and supportive Deferasirox (Exjade) [Iron Chelator] Uses Chronic iron overload d/t transfusion in pts >2 y Action Oral iron chelator Dose Initial 20 mg/kg... 

Efavirenz (Sustiva) [Antiretroviral/NNRTI] Uses Hiv infxns Action Antiretroviral nonnucleoside RTI Dose Adults. 600 mg/d PO qhs Feds. See package insert avoid high-fat meals Caution [D, ] CDC recommends HIV-infected mothers not breast-feed Contra Component sensitivity Disp Caps SE Somnolence, vivid dreams, dizziness, rash, N/V/D Interactions T Effects W/ ritonavir T effects OF CNS depressants, ergot derivatives, midazolam, ritonavir, simvastatin, triazolam, warfarin X effects W/ carbamazepine, phenobarbital, rifabutin, rifampin, saquinavir, St. John s wort i effects OF amprenavir, carbamazepine, clarithromycin, indinavir, phenobarbital, saquinavir, warfarin may alter effectiveness OF OCPs EMS Concurrent EtOH usage can t CNS d ression OD May cause muscle contractions and adverse CNS effects activated charcoal may be effective... 

Estazolam (Prosom) [C-IV] [Hypnotic/Benzodiazepine] Uses Short-term management of insomnia Action Benzodiazepine Dose 1-2 mg PO qhs PRN -1- in hqjatic impair/elderly/debilitated Caution [X, -] t Effects w/ CNS d ressants Contra PRG Disp Tabs SE Somnolence, weakness, palpitations, anaphylaxis, angioedema, amnesia Interactions t Effects W7 amoxicillin, clarithromycin T effects OF diaz am, phen5rtoin, warfarin X effects W7 food X effects OF azole antifungals, digoxin EMS Use caution w/ other benzodiazepines, may need a reduced dose concurrent EtOH and caffeine use can t CNS effects OD May cause alt ed reflexes, drowsiness, CNS depression, slurred speech, and Szs flumazenU can be used as an antidote... 

Ezetimibe/Simvastatin (Vytorin) [Antilipemic/HMG CoA Reductose Inhibitor] Uses H rp cholest olemia Action X Absorption of cholesterol phytost ol w/ HMG-CoA reductase inhibitor Dose 10/10-10/80 mg/d PO w/ cyclosporine or danazol 10/10 mg/d max w/ amio-darone or verapamil 10/20 mg/d max -1- w/ sev e renal insuff Caution [X, -] w/ CYP3A4 inhibitors (Table VI-8), gemfibrozil, niacin >lg/d, danazol, amiodarone, verapamil Contra PRG/lactation livCT Dz, t LFTs Disp Tabs SE HA, GI upset, myalgia, myopathy (muscle pain, weakness, or tendOTiess w/ CK 10 x ULN, rhab-domyolysis), Hep, Infxn Interactions t Risk of myopathy W7 clarithromycin, erythromycin, itraconazole, ketoconazole EMS None OD Sxs unknown symptomatic and supportive... 

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