Verapamil
Phenylalkylamine derivative.
Indicatons
Angina, hypertension, SVT, AF, atrial flutter.
Mechanism
Inhibits influx of extracellular Ca++
into myocardiocytes and vascular smooth muscle cells,
by blocking slow Ca channels.
Adverse effects
Negatively intropic, so digoxin preferred to control rate
in AF. May cause heart block. Prolongs QT interval.
Bradycardia.
Contra-indications
Concurrent β-blocker administration. Sick sinus syndrome.
Wolf-Parkinson-White or Lown-Ganong-Levine with AF (may provoke
ventricular fibrillation).