Compare to the active ingredient of Prevacid 24 HR. Frequent heartburn can occur anytime during the 24-hour period (day or night). Take Amazon Basic Care Lansoprazole Delayed-Release Capsules 15 mg in the morning before eating. The active ingredient lansoprazole 15 mg is clinically proven to treat frequent heartburn. Follow a 14-day course of treatment for frequent heartburn. Not intended for immediate relief of heartburn, this drug may take 1 to 4 days for full effect. Heartburn is a painful, burning sensation in the lower chest or throat that occurs when stomach acid backs up. Amazon Basic Care Lansoprazole Delayed Release Capsules, 15 mg reduce heartburn by decreasing the amount of acid produced in the stomach.