Nifedipine Clarithromycin

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... 

The authors concluded that her sjmiptoms had been precipitated by the introduction of clarithromycin, an inhibitor of CYP isozymes like the other macrolide antibiotics. However, she was also taking omeprazole, another inhibitor, which may have contributed to the problem. All drugs were withdrawn and nifedipine was given, with full recovery within a couple of days. 

Clinically important, potentially hazardous interactions with amlodipine, anisindione, anticoagulants, aprepitant, atorvastatin, barbiturates, benzodiazepines, butabarbital, carbamazepine, chlordiazepoxide, clarithromycin, clonazepam, dorazepate, corticosteroids, cyclosporine, dexamethasone, diazepam, dicumarol, erythromycin, ethotoin, felodipine, flurazepam, fluvastatin, fosphenytoin, isradipine, itraconazole, ketoconazole, lorazepam, lovastatin, mephenytoin, mephobarbital, midazolam, nicardipine, nifedipine, nimodipine, nisoldipine, oxazepam, pentobarbital, phenobarbital, pimozide, pravastatin, primidone, quazepam, rifampin, secobarbital, simvastatin, St John s wort, temazepam, warfarin... 

Clinically important, potentially hazardous interactions with abacavir, atorvastatin, bepridil, bupropion, carbamazepine, clarithromycin, cyclosporine, dexamethasone, digoxin, felodipine, fluticasone propionate, fosamprenavir, itraconazole, ketoconazole, lovastatin, methadone, midazolam, nicardipine, nifedipine, phenobarbital, phenytoin, rifabutin, simvastatin, sirolimus, St John s wort, systemic lidocaine, tacrolimus, tenofovir, trazodone, vinblastine, vincristine, voriconazole, warfarin, zidovudine... 

Acetaminophen, aldrin, alfentanil, amiodarone, aminopyrine, amitriptyline, amprenavir, androstenedione,antipyrine, astemizole, benzphetamine, budesonide, carbamazepine, celecoxib, chlorpromazine, chlorzoxazone, cisapride, clarithromycin, clozapine, cocaine, codeine, cortisol, cyclophosphamide,cyclosporin, dapsone, delavirdine, dextromethorphan, digitoxin, diltiazem, diazepam, erythromycin, 17j3-estradiol, ethinylestradiol, etoposide, felbamate, fentanyl, flutamide, hydroxyarginine, ifosphamide, imipramine, indinavir, ketoconazole, lansoprazole, loratidine, losartan, lovastatin, (iS)"mephen3d in, methadone, mianserin, miconazole, mifepristone, nelfinavir, nevirapine, nicardipine, nifedipine, odansetron, omeprazole, orphenadrine, proguanil, propafenone, quinidine, quinine, rapamycin, retinoic acid, ritonavir, saquinavir, selegiline, serindole, sufentanil, sulfinpyrazone, tacrolimus, tamoxifen, tamsulosin, taxol, teniposide, terfenadine, tetrahydrocannabinol, theophylline, toremifene, triazolam, trimethadone, trimethoprim, troleandomycin, verapamil, warfarin, zatosetron, Zolpidem, zonisamide... 

A4 28 34 clarithromycin, codeine, diazepam, erythromycin, indinavir, midazolam, nifedipine, quinidine, terfenadine, verapamil ketoconazole, itraconazole... 

Erythromycin markedly increases the bioavailability of felodipine. isolated reports describe increased felodipine, nifedipine or verapamil effects and toxicity in patients also given erythromycin. There are also a few reports of verapamil toxicity with clarithromycin, and one with telithromycin. 

Information seems to be limited but the interaction would appear to be established and clinically important, although its incidence is probably low. Anticipate the need to reduce the felodipine or verapamil dosage if erythromycin or clarithromycin, or possibly also telithromycin, is added. Nifedipine may also interact. Other reports suggests that the cardiac toxicity of erythromycin may be increased by verapamil, and diltiazem, and the authors of one of these reports consider that erythromycin should not be used with CYP3A4 inhibitors (that is diltiazem and verapamil). There seem to be no reports of interactions between any of the other calcium-channel blockers and macrolides. However, because of the theoretical possibility of an interaction, many of the manufacturers of calcium-channel blockers warn of the possibility of increased plasma levels and the need to either avoid use with macrolides such as erythromycin, or troleandomycin, or to monitor and reduce doses where necessary. 

Geronimo-Pardo M, Cuartero-del-Pozo AB, Jimenez-Vizuete JM, Cortinas-Saez M, Peyro-Garcia R. Clarithromycin-nifedipine interaction as possible cause of vasodilatory shock. Am PharmacoOterilQOS) 39, 538- 2. 

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