Pepcid AC may cause side effects including diarrhea, constipation, headache and dizziness, according to WebMD. An individual should consult a doctor or pharmacist if any other side effects occur.
If side effects do not improve or become worse, the individual should contact a doctor or pharmacist, explains WebMD. Severe side effects are rare, and a doctor should be consulted immediately if they occur. Severe side effects include abnormal heartbeat, mental or emotional changes, seizure, easy bleeding or bruising, and symptoms of an infection. The individual should also immediately contact a doctor if there are symptoms of a severe allergic reaction, such as difficulty breathing, swelling, severe dizziness, itching or a rash.
Children under 12 years old should not use Pepcid AC unless approved by a doctor, according to WebMD. Individuals who should consult a doctor before using this medicine include those who are older, pregnant or breastfeeding. Individuals should tell a doctor or pharmacist about any allergies, health problems and other medications being taken.
Pepcid AC should not be taken at the same time as other H2 blockers, according to WebMD. An individual who takes Pepcid AC should also avoid operating machinery, limit alcohol, avoid driving and any other activities that demand alertness. Pepcid AC can cause dizziness, which could make these activities risky.