Question: how long does it take for verapamil to work for blood pressure?
Answer: SR means sustained release. This drug is an dihydropyridine L-channel calcium channel blocker, similar to other dihydropyridine drugs like nifedipine, nimodipine and diltiazem. Verapamil is modestly effective for migraine but it takes about 2 weeks to work, and dose may need to be escalated too requiring more time.