Arrhythmias, supraventricular:

IV, 5-10 mg (0.075-0.15 mg/kg) bolus> 2 min; may give additional 10 mg after 30 min if no response.

atrial fibrillation/flutter associated with accessory bypass tract (Wolff-Parkinson-White, Lown - Ganong -Levine) or short PR syndromes;
cardiogenic shock;
congestive heart failure (not due to verapamil-sensitive SVT);
second or third-degree atrioventricular block (without functioning artificial pacemaker);
hypersensitivity to verapamil/other calcium channel antagonists;
sick sinus syndrome (without functioning artificial pacemaker);
symptomatic hypotension (90 mmHg systolic or less); ventricular tachycardia, wide-complex (QRS 0.12 seconds or greater)

M: Headache.
L: Skin rash; CHF or pulmonary edema; hypotension; peripheral edema; constipation; diarrhea; dizziness; flushing; nausea; weakness.
R: Angina; bradycardia; extrapyramidal effect; gingival enlargement; mental depression; tachycardia; thrombocytopenia; drowsiness; dryness of mouth.