Sildenafil Diltiazem

Sildenafil is metabolized predominantly by CYP3A4, which diltiazem inhibits. An interaction of diltiazem with sildenafil has been reported (30). 

The interval after which even short-acting nitrates can be safely given after the use of sildenafil is likely to be substantially longer than 24 hours when elderly patients are concurrently taking a CYP3A4 inhibitor, such as diltiazem. 

Khoury V, Kritharides L. Diltiazem-mediated inhibition of sildenafil metabolism may promote nitrate-induced hypotension. Aust NZ J Med 2000 30(5) 641-2. 

Diltiazem is metabolized by CYP3A4 and was held responsible for unanticipated prolonged hypotension after sublingual glyceryl trinitrate in a patient who underwent coronary angiography 2 days after last using sildenafil (47). 

Benzodiazepines alprazolam, clonazepam, diazepam, midazolam, triazolam, zolpidem Calcium channel blockers diltiazem, nifedipine, nimodipine, verapamil Steroids androgens, estrogens, cortisol Others erythromycin, terfenadine, cyclosporine, dapsone, ketoconazole, lovastatin, lidocaine, alfentanil, amiodarone, astemizole, codeine, sildenafil... 

Clinically important, potentially hazardous interactions with alfentanil, aminophylline, amisulpride, amoxicillin, ampicillin, anticonvulsants, astemizole, atorvastatin, benzodiazepines, bromocriptine, buprenorphine, bupropion, carbamazepine, cilostazol, ciprofloxacin, cisapride, clindamycin, colchicine, cyclosporine, dasatinib, digoxin, dihydroergotamine, diltiazem, disopyramide, enoxacin, eplerenone, ergotamine, eszopiclone, everolimus, fluconazole, fluoxetine, fluvastatin, gatifloxacin, HMG-CoA reductase inhibitors, imatinib, itraconazole, ketoconazole, lomefloxacin, lorazepam, lovastatin, methadone, methylprednisolone, methysergide, midazolam, mizolastine, moxifloxacin, nitrazepam, norfloxacin, ofloxacin, paroxetine, pimozide, pravastatin, quinolones, ranolazine, repaglinide, rupatadine, sertraline, sildenafil, simvastatin, sparfloxacin, sulpiride, tacrolimus, terfenadine, triazolam, troleandomycin, vardenafil, verapamil, vinblastine, warfarin, zaleplon, zolpidem, zuclopenthixol... 

Mexiletine Progesterone Testosterone Sildenafil Trazodone Vineristine Zaleplon Zolpidem Amlodipine Diltiazem Nifedipine Verapamil... 

No clinically relevant interactions appear to occur between sildenafil, tadalafil or vardenafil and most antihypertensive drugs. The exceptions may be diltiazem and verapamil. The potentially serious interactions of sildenafil, tadalafil and vardenafil with the alpha blockers and nitrates are discussed elsewhere. See Phosphodiesterase type-5 inhibitors + Alpha blockers , p.l268 and Phosphodiesterase type-5 inhibitors -I- Nitrates , p.l272. 

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