Name
- Diltiazem.
Class of drug
- Class IV antidysrhythmic agent.
- Calcium channel blocker.
Uses
Action
- Blocks inward movement of calcium ions through the slow channels of active cell membranes.
- Influences myocardial cells, cells within the specialized conduction system in the heart and vascular smooth muscle.
- Vascular smooth muscle is more sensitive to diltiazem than myocardial tissues (relative activity of 7:1). Systemic resistance vessels and large arteries respond to calcium channel blockers more readily than venous capacitance vessels and pulmonary vasculature.
- Myocardial contractility is reduced and the electrical activity depressed.
- A negative inotrope although less effective than verapamil, it retards AV conduction and decreases vascular resistance in cardiac and peripheral arteries and arterioles.
Indications
Primary uses- To control supraventricular tachycardias.
- Sustained and paroxysmal ventricular tachycardias
particularly in cases of hypertrophic cardiomyopathy. - To slow heart rate in dogs with atrial fibrillation as an adjunct to digoxin .
- Management of hypertrophic cardiomyopathy.
Other conditions
- Management of hypertension .
- To limit CNS damage following trauma.
Miscellaneous
- Preferred to verapamil by many because it has effective anti-arrhythmic properties with minimal negative inotropy.
- Diltiazem is preferred to B-blockers for the management of feline hypertrophic cardiomyopathy by some authors because it improves myocardial relaxation, increases ventricular filling and dilates coronary vasculature.
