Before taking cimetidine, tell your doctor or pharmacist if you are allergic to it; or to other H2 blockers (e.g., famotidine, nizatidine, ranitidine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: immune system problems, kidney problems, liver problems, certain lung diseases (chronic obstructive pulmonary disease-COPD), diabetes, other stomach problems (e.g., tumors).
Before taking non-prescription cimetidine for self-treatment, talk with your doctor or pharmacist first if you have any of the following symptoms. These may be signs of a more serious condition. Consult your doctor or pharmacist immediately if you have: difficulty/pain with swallowing food, persistent nausea/vomiting, bloody vomit, vomit that looks like coffee grounds, bloody/black stools, frequent chest pain, persistent stomach pain, heartburn for more than 3 months, trouble breathing with heartburn.
If you are prescribed cimetidine or are considering non-prescription cimetidine for self-treatment, tell your doctor immediately if you have any of these other symptoms that may actually be signs of a more serious condition: heartburn combined with lightheadedness/sweating/dizziness, chest/shoulder/jaw pain (especially with trouble breathing), pain spreading to arms/neck/shoulders, unexplained weight loss.
This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.
Do not use this medication to treat children younger than 12 unless directed by the doctor.
Older adults may be more sensitive to the side effects of this drug, especially confusion and lung infection (pneumonia). Confusion can increase the risk of falling.
Cimetidine should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.
Cimetidine passes into breast milk. Consult your doctor before breast-feeding.