Onset: 3 - 5 min.
potential complications: hypotension due to vasodilation and depressed contractility. Treat with calcium; bradycardia, AV block can be exacerbated, contraindicated with congestive heart failure, synergistic interaction with beta blockers.
note: administration of verapamil to a patient with ventricular tachycardia can be lethal. Verapamil can accelerate heart rate and decrease blood pressure, especially in patients with Wolff-Parkinson-white and wide-complex tachycardia.