Using the antacid medication Pepcid (famotidine) concurrently with Lipitor (atorvastatin), a statin for managing cholesterol levels, can potentially cause interactions that lead to harm.

Famotidine, the active ingredient in Pepcid, is known to decrease the liver's ability to metabolize atorvastatin, leading to increased levels of the drug in the blood [1]. Elevated atorvastatin levels can increase the risk of muscle damage, kidney impairment, and liver problems, which are the primary concerns associated with statin therapy [2].

A study published by the European Pharmaceutical Review suggests that concurrent administration of famotidine and atorvastatin can result in significantly higher atorvastatin levels, which can lead to increased risk of muscle damage, particularly rhabdomyolysis, a severe and potentially life-threatening condition [3].

According to the FDA, famotidine should be avoided with atorvastatin due to the potential for increased side effects and toxicity [4].

While the risk of concurrent use is present, individuals taking both medications should consult with their healthcare provider to assess the potential risks and benefits.

Sources:
[1] - DrugPatentWatch.com - Famotidine/Atorvastatin Interaction
[2] - European Pharmaceutical Review - Atorvastatin-induced rhabdomyolysis: a case report
[3] - European Pharmaceutical Review - Atorvastatin-induced rhabdomyolysis: a case report
[4] - FDA - Famotidine warnings and precautions