Cimetidine blocks histamine 2 receptors which can suppress acid production and reduce symptoms of heartburn.
One of the major downsides to cimetidine is that it has a ton of drug interactions. I discuss many of the common ones in this episode.
Cimetidine is one of a few drugs that has the potential to cause gynecomastia. I discuss the mechanism of this adverse effect in this episode.
Phenytoin concentrations can rise due to the use of cimetidine. I discuss this in the drug interactions section of this episode.