Gallopamil hydrochloride (Methoxyverapamil hydrochloride), a methoxy derivative of Verapamil, is a phenylalkylamine calcium antagonist. Gallopamil hydrochloride inhibits acid secretion in a concentration-dependent manner with an IC50 of 10.9 μM. Gallopamil hydrochloride is a potent antiarrhythmic and vasodilator agent.