Beta blockers Barbiturates

Mood stabilizers phenytoin, valproate, topiramate Sedative/anxiolytics diazepam, barbiturates Beta-blockers propranolol... 

Drugs that may affect sulfonylureas include androgens, anticoagulants, azole antifungals, barbiturates, beta blockers, calcium channel blockers, charcoal, chloramphenicol, cholestyramine, ciprofloxacin, clofibrate, corticosteroids, diazoxide, estrogens, ethanol, fluconazole, gemfibrozil, histamine H2 antagonists, hydantoins,... 

BARBITURATES BETA-BLOCKERS t hypotensive effect Additive hypotensive effect anxiolytics and hypnotics can cause postural i BP Watch for i BP monitor BP at least weekly until stable. Warn patients to report symptoms of hypotension (light-headedness, dizziness on standing, etc.)... 

While the etiology of idiopathic pityriasis rosea is unknown, we do know that various medications have been reported to give rise to this disorder. These are barbiturates, beta-blockers, bismuth, captopril, donidine, gold, griseofulvin, isotretinoin, labetalol, meprobamate, metronidazole, penicillin, and tripelennamine. 

The effects of warfarin may increase when administered with acetaminophen, NSAIDs, beta blockers, disulfiram, isoniazid, chloral hydrate, loop diuretics, aminoglycosides, cimetidine, tetracyclines, and cephalosporins. Oral contraceptives, ascorbic acid, barbiturates, diuretics, and vitamin K decrease the effects of warfarin. Because die effects of warfarin are influenced by many drugp, die patient must notify die nurse or die primary healdi care provider when taking a new drug or discontinuing... 

Drugs that may affect repaglinide include CYP 450 inhibitors (eg, clarithromycin, erythromycin, ketoconazole, miconazole), CYP 450 inducers (eg, barbiturates, carbamazepine, rifampin), beta blockers, calcium channel blockers, chloramphenicol, corticosteroids, coumarins, estrogens, gemfibrozil, isoniazid, itraconazole, levonorgestrel and ethinyl estradiol, MAOIs, nicotinic acid, NSAIDs, oral contraceptives, phenothiazines, phenytoin, probenecid, salicylates, simvastatin, sulfonamides, sympathomimetics, thiazides and other diuretics, and thyroid products. 

Drugs that may affect beta blockers include aluminum salts, barbiturates, calcium salts, cholestyramine, cimetidine, colestipol, diphenhydramine, hydroxychloroquine, NSAIDs, penicillins (ampicillin), rifampin, salicylates, SSRIs, sulfinpyrazole, calcium blockers, oral contraceptives, flecainide, haloperidol, hydralazine, loop diuretics,... 

Drugs that may affect barbiturates include alcohol, charcoal, chloramphenicol, MAO inhibitors, rifampin, and valproic acid. Drugs that may be affected by barbiturates include acetaminophen, anticoagulants, beta blockers, carbamazepine, chloramphenicol, clonazepam, oral contraceptives, corticosteroids, digitoxin, doxorubicin, doxycycline, felodipine, fenoprofen, griseofulvin, hydantoins, methoxyflurane, metronidazole, narcotics, phenmetrazine, phenylbutazone, quinidine, theophylline, and verapamil. 

Rifampin is known to induce the hepatic microsomal enzymes that metabolize various drugs such as acetaminophen, oral anticoagulants, barbiturates, benzodiazepines, beta blockers, chloramphenicol, clofibrate, oral contraceptives, corticosteroids, cyclosporine, disopyramide, estrogens, hydantoins, mexiletine, quinidine, sulfones, sulfonylureas, theophyllines, tocainide, verapamil, digoxin, enalapril, morphine, nifedipine, ondansetron, progestins, protease inhibitors, buspirone, delavirdine, doxycycline, fluoroquinolones, losartan, macrolides, sulfonylureas, tacrolimus, thyroid hormones, TCAs, zolpidem, zidovudine, and ketoconazole. The therapeutic effects of these drugs may be decreased. 

Coadministration of beta-blockers can potentiate rebound hypertension upon discontinuation of medications, and it is therefore recommended that the beta-blocker be withdrawn before the tt2 agonist (Physicians Desk Reference, 2001). Tricyclic antidepressants may also produce changes in sinus node and AV conduction, and it is recommended that they be used cautiously in combination with tt2 agonists (Physicians Desk Reference, 2001). However, in child psychiatric practice, there has been debate about whether there are adverse interactions related to concomitant use of tricyclics and tt2 agonists. Finally, the tt2 agonists may potentiate the effects of CNS depressants (e.g., barbiturates) or other medications that produce sedation, so lower doses of each may be warranted. 

BETA-BLOCKERS BARBITURATES Regular barbiturate use may t elimination of those beta-blockers metabolized by the liver (metoprolol, propanolol, timolol) Barbiturates induce CYP1A2-, CYP2C9- and CYP2C19-mediated metabolism of propanolol Monitor BP at least weekly until stable and watch for t BP... 

Barbiturates and heavy smoking induce nortriptyline metabolism and decrease therapeutic efficacy phenothiazines and haloperidol decrease its metabolism, decreasing therapeutic efficacy methylphenidate, cimetidine, oral contraceptives, propoxyphene, and beta-blockers may inhibit nortriptyline metabolism, increasing plasma levels and toxicity (see Tables 5 through 7). 

Aminoglutethimide, rifampin, barbiturates, charcoal, ketoconazole, smoking (cigarettes and marijuana), sulfinpyrazone, and sympathomimetics (beta-agonists)—all decrease the plasma levels of theophylline, whereas allopu-rinol, beta-blockers (nonselective), calcium-channel blockers, cimetidine, contraceptives, corticosteroids, disulfiram, ephedrine, interferon, macrolides, mexiletine, quinolones, and thiabendazole all increase the plasma levels of theophylline. 

Beta blockers (mainly propranolol) Encalnide and flecalnide Quinidine, procainamide, and disopyramide Propoxyphene Tricyclic antidepressants Others Barbiturates... 

The plasma levels and the effects of beta blockers that are mainly metabolised by the liver (e.g. alprenolol, metoprolol, timolol) are reduced by the barbiturates. Alprenolol concentrations are halved, but the other beta blockers are possibly not affected as much. Beta blockers that are mainly excreted unchanged in the urine (e.g. atenolol, sotalol, nadolol) would not be expected to be affected by the barbiturates. 

Barbiturates are potent liver enzyme inducers that can increase the metabolism and clearance of other drugs from the body. Beta blockers that are removed from the body principally by liver metabolism (e.g. alprenolol, metoprolol, timolol) can therefore possibly be eleaied more quickly in the presence of a barbiturate. 

The interaction between alprenolol and pentobarbital is well documented and likely to be of modest clinical importance when the beta blocker is being used to treat hypertension, and possibly angina. Monitor the effects of alprenolol and increase the dose as necessary. Where possible it may be preferable to replace the barbiturate with a non-interacting alternative, such as one of the benzodiazepines , (p.723), which only have minor effects on the beta blockers, or consider using an alternative non-interacting beta blocker. 

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