Mexiletine Beta blockers

Antiarrhythmics encainide, flecainide, mexiletine Beta-blockers alprenolol, metoprolol, propranolol, timolol Opiates codeine, dextromethorphan, ethylmorphine... 

MEXILETINE BETA-BLOCKERS Risk of bradycardia (occasionally severe), 1 BP and heart failure Additive negative inotropic and chronotropic effects. Also, mexiletine is known to inhibit CYP1 A2-mediated metabolism of propanolol Monitor PR, BP and ECG closely watch for development of heart failure... 

Class Ib antiarrhythmics are usually associated with shortening of the QT interval, and could therefore be expected to reduce the QT prolongation and risk of torsade de pointes seen with amiodarone alone (for examples of this effect of mexiletine see also Mexiletine + Beta blockers, p.268 and Mexiletine + Quinidine , p.269. However, note that the UK manufacturer of mexiletine says that it may exacerbate arrhythmias [as all antiarrhythmics may], but also that it may be used concurrently with amiodarone. The two drugs have been used together successfully. ... 

Agents that may increase theophylline levels include allopurinol, beta blockers (nonselective), calcium channel blockers, cimetidine, oral contraceptives, corticosteroids, disulfiram, ephedrine, influenza virus vaccine, interferon, macrolides, mexiletine, quinolones, thiabendazole, thyroid hormones, carbamazepine, isoniazid, and loop diuretics. 

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. 

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. 

IMATINIB 1. ANTIARRHYTHMICS -flecainide, mexiletine, propafenone 2. ANTIDEPRESSANTS - fluoxetine, paroxetine, TCAs, trazodone, venlafaxine 3. ANTIPSYCHOTICS -clozapine, haloperidol, perphenazine, risperidone, thioridazine 4. BETA-BLOCKERS - metoprolol, propanolol, timolol 5. DONEPEZIL 6. METHAMPHETAMINE Imatinib may cause t plasma concentrations of these drugs, with a risk of toxic effects Inhibition of CYP2D6-mediated metabolism of these drugs Watch for early features of toxicity of these drugs... 

Class IB drugs such as lidocaine and mexiletine typically block sodium channels and decrease the action potential duration. Mexiletine, but not lidocaine, is orally active. The answer is (G). Verapamil is the calcium channel blocker in this list. (Adenosine and beta-blockers also slow AV conduction but do not act primarily on calcium channels.) The answer is (J). 

The concurrent use of mexiletine and beta blockers can be clinically useful Mexiletine may reduce the QT prolonging effects of sotalol... 

Selertive serotonin reuptake inhibitors may decrease metabolism of alpha/beta blockers, benzodiazepines, carbamazepine, cimetidine, clozapine, fesoterodine, haloperidol, methadone, mexiletine, phenytoin, propafenone, respiradone, tamoxifen, galantamine, respiradone, thioridazine. 

Smoking cessation, with or without nicotine substitutes, may alter response to concomitant medication in ex-smokers. Smoking may affect alcohol, benzodiazepines, beta-adrenergic blockers, caffeine, clozapine, fluvoxamine, olanzapine, tacrine, theophylline, clorazepate, lidocaine (oral), estradiol, flecanide, imipramine, heparin, insulin, mexiletine, opioids, propranolol, catecholamines, and cortisol. 

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