Medication guide
Cimetidine
- Generic name
- Cimetidine
- Common brand names
- Tagamet HB
- Medication class
- H2 receptor antagonist
Overview
Its medication class is H2 receptor antagonist. Common uses include Acid suppression. Product forms and labels can differ, so follow the specific package instructions and ask a pharmacist or qualified healthcare professional about individual questions.
How to Take it
- Route
- Oral antacid/anti-reflux product.
- Time of day
- Use after meals and at bedtime for reflux or heartburn; PPIs often before breakfast.
- With food/water
- Take with water; PPIs should be taken with water before first meal.
- Preparation
- Swallow tablets/capsules whole; do not exceed label antacid spacing with other meds.
- Safe dose
- Use lowest effective acid-relief dose.
- Max dose
- Adhere to OTC daily total for each ingredient class.
- Frequency
- 1–4 times/day depending active and symptom control.
- Other recommendations
- If symptoms continue >2 weeks or recur, seek clinician evaluation.
Common uses
- Acid suppression
Common side effects
- Headache
- fatigue
- diarrhea
- constipation
- dizziness
- gynecomastia (rare)
- rash
- and dry mouth
Important warnings
- Highest interaction burden among H2 blockers (CYP inhibition). Review all concomitant drugs (warfarin, anticonvulsants, cardiac medicines). Avoid prolonged use without periodic reassessment, especially in liver disease and older adults. Use caution if cognitive confusion, endocrine symptoms, or severe GI symptoms occur.
General interactions information
Inhibits metabolism of many medicines (e.g., warfarin, phenytoin, theophylline, others)
Sources / references
- Cimetidine — MedlinePlus
U.S. National Library of Medicine
These references offer further reading. A source link does not establish that a clinician has reviewed every statement in this guide.
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