How is Isoptin SR Supplied ISOPTIN SR 240 mg tablets are supplied as light green, capsule shaped, scored, film-coated tablets containing 240 mg of verapamil hydrochloride. Food thus produces slight decrease in bioavailability AUC kopen isoptin geen rx but narrower peak-to-trough ratio. Variable results on clearance have been obtained in acute studies of healthy clearance of verapamil was either reduced or unchanged. Although risk of this occurring with oral verapamil has not been established, such patients receiving oral verapamil may be at risk and its use in these patients is contraindicated see Contraindications. Patients receiving these combinations should be appropriately monitored. The antihypertensive effects of Isoptin tablets are evident within the first week of therapy. Half-life of verapamil increases during titration due to saturation of hepatic enzyme systems as plasma verapamil levels rise.