Introduction

Name

• Cimetidine.

Class of drug

• H2-antihistamine.

Description

Chemical name

• N-cyano-N'-methyl-N"-[2-[[(5-methyl-1H-imidazol-4-yl)methyl]thio]ethyl]guanidine.

Molecular formula

• C10H16N6S.

Physical properties

• Tablets.

Storage requirements

• In a dry environment.

Uses

Indications

• Gastric Gastric ulceration and duodenal ulcers.
• Uremic Uremia gastritis.
• Stress or drug-related erosive gastritis.
• Esophagitis Esophagitis.
• Hypersecretory conditions secondary to gastrinoma Pancreas: neoplasia: gastrinoma or mastocytosis Skin: mastocytoma.
• Adjunctively to reverse metabolic alkalosis Acid base imbalance.
• May be useful as an immunomodulating agent by preventing activation of suppressor T cells by histamine although evidence is lacking.

Administration

Precautions

Interactions

with other drugs

Drugs affected by cimetidine (increased plasma levels)

• Beta-blockers, eg propranolol Propranolol.
• Calcium channel blockers, eg verapamil Verapamil.
• Diazepam Diazepam.
• Lignocaine Lidocaine.
• Metronidazole Metronidazole.
• Pethidine Pethidine.
• Phenytoin Phenytoin.
• Quinidine Quinidine.
• Theophylline Theophylline.
• Warfarin Warfarin.
• Phenobarbital Phenobarbital.

Sucralfate

• Sucralfate may reduce bioavailability of H2 antagonists.
• While there is little evidence to suggest that this is clinically significant it may be wise to administer sucralfate Sucralfate at least 30 minutes before cimetidine.

Antacids, digoxin, ketoconazole, metoclopropamide

• Stagger oral doses of cimetidine when used with these drugs Digoxin Ketoconazole Metoclopramide by 2 hours.

Adverse Reactions

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• Based on BSAVA Small Animal Formulary. Ramsey I (2017) 9th edn. Cheltenham: BSAVA.