Oxazepam Cimetidine

Cimetidine can impair benzodiazepine metabolism and lead to adverse effects (SEDA-18, 43). In contrast, a few benzodiazepines are metabolized exclusively by glucuro-nide conjugation (lorazepam, oxazepam, temazepam), and are therefore unaffected by concomitant therapy with cimetidine and other oxidation inhibitors (123). 

The metabolism of lorazepam (e.g., Ativan), oxazepam (e.g., Serax), and temazepam (e.g., Restoril) are not likely to be affected, and one of these agents may be preferred when a benzodiazepine is indicated in a patient being treated with cimetidine. The experience with ranitidine (e.g., Zantac), famotidine (Pepcid), and nizatidine (Axid) suggests that these agents are not likely to inhibit hepatic enzyme systems, and these other histamine H2-receptor antagonists are less likely than cimetidine to interact with other drugs that are metabolized via these pathways. 

Greenblatt DJ, Abernethy DR, Koepke HH, Shader RL Interaction of cimetidine with oxazepam, lorazepam, and flurazepam. J Chn Pharmacol 1984 24(4) 187-93. 

Also analyzed acebutolol, acepromazine, acetaminophen, acetazolamide, acetophenazine, albuterol, amitriptyline, amobarbital, amoxapine, antipsrrine, atenolol, atropine, azata-dine, baclofen, benzocaine, bromocriptine, brompheniramine, brotizolam, bupivacaine, buspirone, butabarbital, butalbital, caffeine, carbamazepine, cetirizine, chlorqyclizine, chlordiazepoxide, chlormezanone, chloroquine, chlorpheniramine, chlorpromazine, chlorpropamide, chlorprothixene, chlorthalidone, chlorzoxazone, cimetidine, cisapride, clomipramine, clonazepam, clonidine, clozapine, cocaine, codeine, colchicine, qyclizine, (yclo-benzaprine, dantrolene, desipramine, diazepam, diclofenac, diflunisal, diltiazem, diphenhydramine, diphenidol, dipheno late, dipyridamole, disopyramide, dobutamine, doxapram, doxepin, droperidol, encainide, ethidium bromide, ethopropazine, fenoprofen, fentanyl, flavoxate, fluoxetine, fluphenazine, flurazepam, flurbiprofen, fluvoxamine, fii-rosemide, glutethimide, glyburide, guaifenesin, haloperidol, homatropine, hydralazine, hydrochlorothiazide, hydrocodone, hydromorphone, hydro g chloroquine, hydroxyzine, ibuprofen, imipramine, indomethacin, ketoconazole, ketoprofen, ketorolac, labetalol, le-vorphanol, lidocaine, loratadine, lorazepam, lovastatin, loxapine, mazindol, mefenamic acid, meperidine, mephenytoin, mepivacaine, mesoridazine, metaproterenol, methadone, methdilazine, methocarbamol, methotrexate, methotrimeprazine, methoxamine, methyl-dopa, methylphenidate, metoclopramide, metolazone, metoprolol, metronidazole, midazolam, moclobemide, morphine, nadolol, nalbuphine, naloxone, naphazoline, naproxen, nifedipine, nizatidine, norepinephrine, nortriptyline, oxazepam, oxycodone, oxymetazo-line, paroxetine, pemoline, pentazocine, pentobarbital, pentoxifylline, perphenazine, pheniramine, phenobarbital, phenol, phenolphthalein, phentolamine, phenylbutazone, phenyltoloxamine, phenytoin, pimozide, pindolol, piroxicam, pramoxine, prazepam, prazosin, probenecid, procainamide, procaine, prochlorperazine, procyclidine, promazine, promethazine, propafenone, propantheline, propiomazine, propofol, propranolol, protriptyline, quazepam, quinidine, quinine, racemethorphan, ranitidine, remoxipride, risperidone, salicylic acid, scopolamine, secobarbital, sertraline, sotalol, spironolactone, sulfinpyrazone, sulindac, temazepam, terbutaline, terfenadine, tetracaine, theophylline, thiethyl-perazine, thiopental, thioridazine, thiothixene, timolol, tocainide, tolbutamide, tolmetin, trazodone, triamterene, triazolam, trifluoperazine, triflupromazine, trimeprazine, trimethoprim, trimipramine, verapamil, warfarin, xylometazoline, yohimbine, zopiclone... 

Wong, S.H.Y. McHugh, S.L. Dolan, J. Cohen, K.A. Tricyclic antidepressant analysis by reversed-phase liquid chromatography using phenyl columns. J.Liq.Chromatogr., 1986, 9, 2511-2538 [also acetaminophen, amobarbital, amoxapine, barbital, chlordiazepoxide, chlorpromazine, cimetidine, clomipramine, codeine, desipramine, desmethyldoxepin, diazepam, doxepin, fluphenazine, flurazepam, glutethimide, hydroxyamoxapine, imipramine, lorazepam, maprotiline, meperidine, metabolites, nortriptyline, oxazepam, pentobarbital, perphenazine, phenobarbital, phenytoin, propoxyphene, protriptyline, secobarbital, thioridazine, trazodone]... 

Simultaneous amoxapine, chlordiazepoxide, chlorpromazine, cimetidine, desipramine, diazepam, doxepin, flurazepam, imipramine, lorazepam, norfluoxetine, nortriptyline, oxazepam, pentobarbital, perphenazine, phenobarbital, phen5doin, prochlorperazine, secobarbital, thioridazine, trifluoperazine Noninterfering acetaminophen, codeine, meperidine Interfering amitriptyline, propo q>hene... 

Svirbely, J.E. Pesce, A.J. TWmethoprim analysis by LC. J.Liq.Chromatogr., 1988,11, 1075—1085 [LOD 50 ng/mL serum plasma dialysate urine CSF SPE interfering atenolol, procainamide, oxazepam non-interfering acetaminophen, amitriptyline, ampicillin, caffeine, cefitoxin, chlordiazepoxide, chlorpheniramine, chlorpromazine, cimetidine, clonidine, desipramine, diazepam, digoxin, diphenhydramine, doxepin, doxylamine, erythromycin, flurazepam, imipramine, lidocEune, minoxidil, nadolol, nortriptyline, prazosin, propranolol, quinidine, theophylline, thioridazine]... 

Cimetidine inhibits the liver enzymes associated with oxidative metabolism. Hence, the serum levels of most benzodiazepines affected by this metabolic pathway (aiprazoiam, diazepam, cbiordiazepoxide, fiurazepam, nitrazepam, and triazoiam) were found to be increased when cimetidine was co-administered. Benzodiazepines metabolized by glucuronide conjugation (iorazepam, oxazepam, and temazepam) are not affected by cimetidine. Ranitidine probably has no significant interaction with most benzodiazepines. 

In contrast, cimetidine does not normally interact with clobazam, clo-tiazepam, lormetazepam, oxazepam or temazepam, although prolonged post-operative sedation was seen in one patient given oxazepam and cimetidine. ... 

Lorazepam, oxazepam and temazepam are metabolised by a different metabolic pathway involving glucuronidation, which is not affected by cimetidine, and so they do not usually interact. 

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