Warfarin Beta blockers

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... 

Sedative/hypnotics zopiclone Beta-blockers propranolol, warfarin, theophylline... 

Drugs that may be affected by SSRIs Drugs that may be affected by SSRIs include alcohol, benzodiazepines, beta blockers, buspirone, carbamazepine, cisapride, clozapine, cyclosporine, diltiazem, digoxin, haloperidol, hydantoins, lithium, methadone, mexiletine, nonsedating antihistamines, NSAIDs, olanzapine, phenothiazines, phenytoin, pimozide, procyclidine, ritonavir, ropivacaine, sumatriptan, sulfonylureas, sympathomimetics, tacrine, theophylline, tolbutamide, tricyclic antidepressants, and warfarin. 

As it inhibits microsomal cytochrome P450 cimetidine has a high potential for drug interactions not shared by the other H2 receptor antagonists. The oxidative metabolism of agents such as anticoagulants, most antiepileptics, some beta-blockers, warfarin, theophylline and many hypnotics, neuroleptics and antidepressants may be reduced, leading to increased effects. 

Combinations of nitrates with beta blockers used initially with supplemental oxygen. To prevent thrombosis (and MI) heparin, warfarin, and antiplatelets (ASA, ticlopidine). 

Answer E. Cimetidine is an inhibitor of the hepatic cytochrome P450 isoform that metabolizes phenytoin, consequently decreases its clearance, and thus increases its elimination half-life. The hepatic metabolism of many other drugs can be inhibited by cimeti-dine, possibly necessitating dose reductions to avoid toxicity, including beta blockers, iso-niazid, procainamide, metronidazole, tricyclic antidepressants, and warfarin. 

Cimetidine 300mg po tid 800 mg po bid 60% 100% 75% 25% Multiple drug-drug interactions beta blockers, sulfonylurea, theophylline, warfarin, etc... 

Displaces warfarin from plasma protein binding sites. Reduces natriuretic and diuretic effects of furosemide and antihypertensive effects of thiazides, beta blockers, prazosin, and captopril. 

The effects of the coumarins are not normally altered by any beta blocker. However, propranolol has caused small increases in warfarin levels in a couple of studies, and one or two isolated cases of increased warfarin and phenindione effects have been reported. 

In 6 patients stabilised on warfarin, acebutolol 300 mg three times daily for 3 days had no effect on prothrombin time response. Similarly, in one patient taking warfarin, neither atenolol 100 mg daily nor metoprolol 100 mg twice daily for 3 weeks had any effect on prothrombin time. Similarly, in studies in healthy subjects the following beta blockers had no clinically relevant effects on the pharmacokinetics and/or anticoagulant response to warfarin atenolol 100 mg daily, betaxolol 20 mg daily, bisoprolol 10 mg daily, esmolol, or metoprolol 100 mg twice daily. In contrast, the minimum steady state plasma warfarin levels of 6 healthy subjects rose by 15% when they took propranolol 80 mg twice daily in one study." Similarly, in another study in 6 healthy subjects given propranolol 80 mg twice daily for 7 days with a single dose of warfarin on day 4, the AUC of warfarin was increased by 16.3% and the in maximum serum level was increased by 23%, but there was no change in the prothrombin time. A patient stabilised on warfarin had a rise in his Brit-... 

Overall, the findings of these pharmacological studies in patients and healthy subjects confirm the general clinical experience that the effects of the coumarin anticoagulants are not normally altered hy the beta blockers. No special precautions are needed on concurrent use. The only uncertainty is with propranolol, which has shown a small rise in warfarin levels in two studies, and for which there are a couple of reports of possible increased anticoagulant responses of warfarin and phenindione. Even so, a clinically significant interaction would seem to be extremely rare. 

Orthostatic hypotension occurred when levosimendan was given with isosorbide mononitrate. The haemodynamic effects of levosimendan were not significantly altered by captopiil, carvedilol or other unnamed beta blockers, or felodipine. Levosimendan does not alter the effects of warfarin. Itraconazole does not alter the pharmacokinetics of levosimendan. Levosimendan appears not to interact adversely with alcohoL... 

NSAID and warfarin ACE inhibitors and K-sparing dinretic Verapamil and beta-adrenergic antagonists Nenromnscnlar (NM) blockers and aminoglycosides Alcohol and benzodiazpines Thioridazine and halofantrine Clozapine and co-trimoxazole Increased risk of bleeding Increased risk of hyperkalaemia Bradycardia and asystole Increased NM blockade Increased sedation Increased risk of QT interval prolongation Increased risk of bone marrow suppression... 

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