Cytochrome P450 : Alphabetical drug list
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1A2 2C9 2C19 2D6 2E1 3A4
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Drug CYP interaction Clinical consequences
caffeine CYP1A2 : low activity (neonates) toxicity
3A4 : metabolism ?
Calcium channel blockers (dihydropyridine) CYP3A4 : METABOLISM less effective with high activity;
low 3A4 activity delays clearance : hypotension [Clin Pharmacokinet 2000 Jan;38(1):41-57 ]
CYP3A4 : INHIBIT ? interactions
2D6, 2C9 (also inhibited: most notably by nicardipine) [Drug Metab Dispos 2000 Feb;28(2):125-30] ?
cannabinoids (eg. cannabidiol), cannabis 3A4 : metabolism AND inhibition potential for interaction with eg. cyclosporine [Xenobiotica 1996 Mar;26(3):275-84]
carbamazepine CYP3A4 : INDUCES hastens metabolism of valproic acid, clonazepam, ethosuximide, lamotrigine, topiramate, tiagabine and remacemide;
also tricyclic antidepressants, antipsychotics, steroid oral contraceptives, glucocorticoids, oral anticoagulants, cyclosporine, theophylline
CYP3A4 : metabolism toxicity with eg. macrolides, stiripentol, remacemide, acetazolamide, macrolide antibiotics, isoniazid, metronidazole, certain antidepressants, verapamil, diltiazem, cimetidine, danazol and (dextro)propoxyphene;
rapid removal with phenytoin, phenobarbital, primidone [Clin Pharmacokinet 1996 Sep;31(3):198-214]
CYP2C9 : ? induces ? less warfarin effect
carisoprodol CYP2C19 : low activity less effective (less formation of meprobamate)
carvedilol (See also beta blockers) 2D6 (some contribution from other CYPs e.g. 2C9, and non-oxidative elimination) "possibly of little significance" [Drug Metab Dispos 1997 Aug;25(8):970-7], but low 2D6 may result in more alpha blockade
celecoxib 2C9 : metabolism [Clin Ther 1999 Jul;21(7):1131-57], [Clin Pharmacokinet 2000 Mar;38(3):225-42] potential for interactions.
2D6 : INHIBITS ? warfarin - increased effect!
cerivastatin (See also HMG Co-A reductase inhibitors) 3A4 : substrate ?? significance (minor interaction with erythromycin) ; no interaction with nifedipine
chlorpheniramine 3A4 : metabolism
2D6 : inhibits (Ki 11 µM)
chlorpromazine (See also Antipsychotics) CYP2D6 : metabolism and inhibition
(? also 3A4 metabolism)
e.g. inhibition of codeine effect
cimetidine CYP1A2 : INHIBITS ( >> ranitidine) ?
CYP2D6 : INHIBITS (>>> ranitidine) increases systemic effect of timolol opthalmic drops! [J Clin Pharmacol 2000 Feb;40(2):193-9]
3A4 : INHIBITS (>>> ranitidine) (and metabolism ?) ?
ciprofibrate 3A4 (see fibrates)
ciprofloxacin CYP1A2 : INHIBITS ?
3A4 : INHIBITS (see also Quinolones)
cisapride CYP3A4 METABOLISM 3A4 inhibition gives polymorphic ventricular tachycardia eg with clarithromycin , nefazodone, diltiazem, saquinavir, grapefruit juice [Clin Pharmacol Ther 1999 Apr;65(4):395-401]
citalopram (SSRI) 2C19 : metabolism ?
3A4 : metabolism ?
2D6 : metabolism (mild inhibition) ?
clarithromycin 3A4 : metabolism levels may increase with ritonavir, omeprazole; low with rifampicin
3A4 : INHIBITS caution with cisapride, pimozide, midazolam, &c; carbamazepine, cyclosporine, theophylline, [see: Clin Pharmacokinet 1999 Nov;37(5):385-98 ??]
clemastine (1st generation antihistamine) 2D6 : INHIBITS (Ki ~ 2 µM) significant interaction feasible
clindamycin 3A4 : metabolism ?
clomipramine (see Tricyclics) 1A2 : metabolism ?
2C19 : metabolism ?
2D6 : metabolism
also ? 3A4 metabolism
2D6 : INHIBITS e.g. decreased codeine action
clopidogrel activated by CYP1A Does NOT affect aminophyllin clearance [Semin Thromb Hemost 1999;25 Suppl 2:65-8]
clozapine CYP1A2 : METABOLISM
(? also 2D6)
lower levels with cigarette smoking, carbamazepine; raised with caffeine, erythromycin
cocaine 3A4 : metabolism {norcocaine is oxidation product, responsible for hepatotoxicity}
2d6 : INHIBITS (0.07 µmol) Strong interaction potential
codeine : CYP2D6 activation to morphine is central to codeine's effects CYP2D6 : low activity inadequate analgesia;
fluoxetine could be used to treat codeine dependence ;
gastrointestinal effect of codeine is also probably mediated by metabolite morphine
CYP2D6: raised activity excessive morphine production,
severe epigastric pain! [Ther Drug Monit 1997 Oct;19(5):543-4]
CYP3A4 : metabolism to norcodeine (N-demethylation) ? (rifampicin attenuates codeine effect [J Pharmacol Exp Ther 1997 Apr;281(1):330-6] )
cortisol : see hydrocortisone
coumarin 2A6 : metabolism (coumarin 7 hydroxylase) ?
cyclobenzaprine CYP1A2 substrate ?
3A4 : substrate ?
cyclophosphamide (prodrug, activated by 2B6) CYP2B6 : metabolism ?
cyclosporine (cyclosporin A)
{for a note on 'cyclosporine-sparing agents' see [Clin Pharmacokinet 1997 May;32(5):357-67] }
CYP3A4 : hi activity less effective : transplant rejection. Potentially occurs with: rifampicin, sulfadimidine, phenobarbital, phenytoin, phenylbutazone, dexamethasone, sulfinpyrazone, and carbamazepine.
CYP3A4 : low activity toxicity (eg with nefazodone) fluconazole increases cyA bioavailability many other drugs eg clarithromycin, quinolones, glibenclamide, ketoconazole, amiodarone
Other potential drugs causing CYA toxicity include: triacetyloleandomycin, erythromycin, josamycin, midecamycin, miconazole, midazolam, nifedipine, diltiazem, verapamil, nicardipine, ergotamine, dihydroergotamine, glibenclamide, bromocriptine, ethinylestradiol, progesterone, cortisol, prednisone, prednisolone, methylprednisolone [Drug Metab Dispos 1990 Sep-Oct;18(5):595-606]
3A4 : INHIBITS drug toxicity eg statins

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1A2 2C9 2C19 2D6 2E1 3A4

Page author: jo@anaesthetist.com Last update: 2000-6-22