Nifedipine Phenytoin

Ahmad S. Nifedipine-phenytoin interaction. J Am Coll Cardiol 1984 3(6) 1582. 

A sampling of commonly used drugs with cytochrome P450-mediated metabolism inhibited by ketoconazole or other azoles includes chlordiazepoxide, cisapride, cyclosporine, didanosine, fluoxetine, loratadine, lovastatin, methadone, nifedipine, phenytoin, quinidine. theophylline, verapamil, warfarin, and zolpidem. 

Noninterfering albuterol, aspirin, chlorpropamide, chlorthalidone, codeine, diazepam, diclofenac, dipyrone, enalapril, furosemide, heparin, nifedipine, phenytoin, ranitidine, warfarin... 

The H2RAs are generally well tolerated. The most common adverse effects are headache, somnolence, fatigue, dizziness, and either constipation or diarrhea. Cimetidine may inhibit the metabolism of theophylline, warfarin, phenytoin, nifedipine, and propranolol, among other drugs. 

Gingival hyperplasia Antiepileptics (phenytoin), immunosuppressant drugs, calcium channel antagonists (felodipin, amlodipin, nifedipin)... 

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... 

Cardiac depressant effects may occur when verapamil or diltiazem is combined with a (p-adrenoceptor antagonoist or a cardiac glycoside. Nifedipine and verapamil are metabolised by cytochrome P-450 3A4. Inhibitors of this enzyme, e.g. HIV-protease inhibitors, cimetidine, fluoxetine, ketoconazole, erythromycin, will increase plasma levels and the dose should be carefully monitored. Conversely, enzyme inducers, e.g. carbamazepine, rifampicin, phenytoin, will decrease their plasma concentrations. 

Phenobarbital Enhances phasic GABAa receptor responses reduces excitatory synaptic responses Nearly complete absorption not significantly bound to plasma proteins peak concentrations in Vi to 4 h no active metabolites tjy2 varies from 75 to 125 h Generalized tonic-clonic seizures, partial seizures, myoclonic seizures, generalized seizures, neonatal seizures, status epilepticus Toxicity Sedation, cognitive issues, ataxia, hyperactivity Interactions Valproate, carbamazepine, felbamate, phenytoin, cyclosporine, felodipine, lamotrigine, nifedipine, nimodipine, steroids, theophylline, verapamil, others... 

Isoniazid Avasimibe Bosentan Carbam- a2epine" Clotrimazole Cyproterone acetate Hyperforin Lovastatin Mifepristone Nelfinavir Nifedipine Omeprazole Paclitaxel Phenobarbital Phenytoin Rifabutin Rifampin"" Rifapentine Ritonavir Simvastatin Sulfinpyrazole Topotecan Troglitazone Troleandomycin Vitamin E Vitamin K2 Yin zhi wuang... 

CALCIUM CHANNEL BLOCKERS PHENYTOIN 1. Phenytoin levels are t by diltiazem and possibly nifedipine and isradipine 2.1 plasma concentrations of diltiazem, felodipine, nisoldipine, verapamil and possibly nimodipine 1. Postulated to be due to inhibition of CYP3A4-mediated metabolism of phenytoin. Diltiazem is also known to inhibit intestinal P-gp, which may t the bioavailability of phenytoin 2. Phenytoin induces CYP3A4, which metabolizes calcium channel blockers 1. Monitor phenytoin levels when initiating calcium channel blockers, particularly diltiazem and verapamil 2. Monitor PR and BP closely watch for t BP when starting phenytoin in patients already on calcium channel blockers... 

Gingival hyperplasia, similar to that seen with phenytoin and ciclosporin, is a rare but well-recognized adverse effect of nifedipine (88). It has also been reported in patients taking felodipine (89,90), nitrendipine (SEDA-16, 200), and verapamil (91), suggesting that this adverse effect is a class effect. Only one case of gingival hyperplasia related to calcium channel blockers was reported to the Norwegian Adverse Drug Reaction Committee up to 1991, despite their widespread use (92). However,... 

Increased serum phenytoin concentrations have been reported after the introduction of nifedipine (57,58). 

In spite of the many papers published on them and the often major improvements in bioavailability and the stability they provide, solid solutions and dispersions in povidone have up to now only found use in a few commercial products. Tables 81 and 82 show how phenytoin and nifedipine, for example, can be processed relatively straightforwardly in the form of a physical mixture or coprecipitate with povidone. Cyclosporine, oxodipine and spironolactone tablets or nor-ethindrone suppositories are further examples [508,533,566,575]. It is interesting to compare the dissolution data for phenytoin after manufacture and after two years storage at room temperature in Figs. 52 and 53 no major difference can be seen. 

Kidd RS, Straughn AB, Meyer MC, et al Pharmacokinetics of chlorpheniramine, phenytoin, glipizide and nifedipine in an individual homozygous for the CYP2C9 3 allele. Pharmacogenetics 9 71-80,1999 Kinirons MT, Crome P Clinical pharmacokinetic considerations in the elderly an update. Clin Pharmacokinet 33 302-312,1997... 

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... 

Clinically important, potentially hazardous interactions with alfentanil, alfuzosin, alprazolam, amiodarone, amprenavir, aprepitant, astemizole, atazanavir, bepridil, buprenorphine, bupropion, carbamazepine, chlordiazepoxide, ciclesonide, clozapine, conivaptan, cyclosporine, cyproterone, dasatinib, diazepam, dihydroergotamine, ergot alkaloids, estazolam, eszopidone, etravirine, ezetimibe, fentanyl, fesoterodine, flecainide, flurazepam, fluticasone, halazepam, ivabradine, ixabepilone, ketoconazole, lapatinib, levothyroxine, meperidine, meptazinol, methysergide, midazolam, nifedipine, nilotinib, oral contraceptives, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quazepam, quinidine, ranolazine, rifabutin, rifampin, rifapentine, rimonabant, rivaroxaban, saquinavir, sildenafil, silodosin, simvastatin, solifenacin, St John s wort, tadalafil, temsirolimus, trabectedin, triazolam, vardenafil, voriconazole, zolpidem... 

CYP3A3/4 Cyclosporine Verapamil Nifedipine blockers Phenytoin Rifampin Barbiturates Erythromycin Verapamil Ketoconazole Grapefruit juice (Yes)" Erythromcyin Midazolam... 

Lanza, F. Hall, A.J. Sellergren, B. Bereczki, A. Horvai, G. Bayoudh, S. Cormack, P. A. G. Sherrington D.C., Development of a semiautomated procedure for the synthesis and evaluation of molecularly imprinted polymers applied to the search for functional monomers for phenytoin and nifedipine, Anal. Chim. Acta. 2001, 435, 91-106... 

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