H2 blockers may take several days to take effect. Some patients may continue to take antacids in the interim to alleviate their symptoms. However, antacids affect the stomach’s ability to absorb other medications. Therefore, antacids and H2 blockers should be taken at least an hour apart.

Patients who smoke cigarettes may find that this habit negates the beneficial effects of H2 blockers. Cigarette smoke increases the production of acid in the stomach, particularly overnight. It is best if patients refrain from smoking altogether. However, those who find they cannot do so should at least avoid smoking after their final daily dose of an H2 blocker.

Consumption of alcohol while taking an H2 blocker may result in increased levels of alcohol in the blood.

Finally, patients should inform their physician that they are taking H2 blockers before they are scheduled to have skin testing for allergies or testing to determine the level of acid their stomach produces.