Given zantac (ranitidine) 150mg to take twice a day. half a tablet once a day works the same. is this ok instead of 2? male 22

Dose dependent...: Zantac (ranitidine) is an h2-blocker that comes in many strengths because the more drug you take the more effectively it modulates acid production. Full prescription dosing is 300 mg twice daily to heal acid-related injury. For relief of indigestion without injury however use the lowest dose that provides you benefit (to avoid potential side effects).