Calcium channel blockers negative chronotropic effects

Verapamil. Verapamil hydrochloride is a pbenyl alkyl amine and is considered the prototype of the Class I calcium channel blockers. Verapamil is also a potent inhibitor of coronary artery spasm and is useful in Prinzmetal s angina and in unstable angina at rest. Verapamil produces negative chronotropic and inotropic effects. These two actions reduce myocardial oxygen consumption and probably account for the effectiveness of verapamil in chronic stable effort angina (98,99). Moreover, verapamil is an effective antihypertensive agent. 

Propranolol and nadolol also have been used successfully in combination with certain calcium entry blockers, particularly nifedipine, for the treatment of secondary angina. Caution should be used, however, when combining a p-blocker and a calcium channel blocker, such as verapamil or diltiazem, since the negative inotropic and chronotropic effects of this combination may lead to severe bradycardia, arteriovenous nodal block, or decompensated congestive heart failure. 

AMIODARONE CALCIUM CHANNEL BLOCKERS Risk of bradycardia, AV block and 1 BP when amiodarone coadministered with diltiazem or verapamil Additive negative inotropic and chronotropic effect. Also, amiodarone inhibits intestinal P-gp, which t the bioavailability of diltiazem and verapamil Monitor PR, BP and ECG closely watch for heart failure... 

CALCIUM CHANNEL BLOCKERS BACLOFEN AND TIZANIDINE t hypotensive effect with baclofen of tizanidine. Risk of bradycardia with tizanidine Additive hypotensive effect. Tizanidine has a negative inotropic and chronotropic effect Monitor BP at least weekly until stable. Warn patients to report symptoms of hypotension (light-headedness, dizziness on standing, etc.)... 

BACLOFEN, TIZANIDINE 1. ANAESTHETICS - general 2. ANTICANCER AND IMMUNOMODULATING DRUGS - IL-2 3. ANTIDEPRESSANTS - MAOIs 4. ANTI HYPERTENSIVES AND HEART FAILURE DRUGS 5. ANTI-PSYCHOTICS 6. ANXIOLYTICS AND HYPNOTICS 7. BETA-BLOCKERS 8. CALCIUM CHANNEL BLOCKERS 9. DIURETICS 10. NITRATES 11. PERIPHERAL VASODILATORS-moxisylyte (thymoxamine) 12. POTASSIUM CHANNEL ACTIVATORS t hypotensive effect Additive hypotensive effect. Tizanidine also has a negative chronotropic effect and may cause additive bradycardia with beta-blockers and calcium channel blockers Monitor BP at least weekly until stable. Warn patients to report symptoms of hypotension (light-headedness, dizziness on standing, etc.)... 

BACLOFEN, TIZANIDINE ANAESTHETICS - GENERAL t hypotensive effect Additive hypotensive effect. Tizanidine also has a negative chronotropic effect and may cause additive bradycardia with beta-blockers and calcium channel blockers Monitor BP closely, especially during induction of anaesthesia... 

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