- for PUD, prophylaxis in trauma, burns, surgery; 
- Adult: active PUD: 300 mg PO/IV tid-qid, or 400 mg PO bid; 
- over 90% of ulcers should heal after 12 wks of therapy
- Hosp Prac. 1979 
- ulcers which have not healed after 12 wks, probably will not heal w/ H2 Blockers; 
- for recurrent duodenal Ulcer prophylaxis: 400 mg PO qhs; 
- active benign gastric ulcer: 300 mg PO qid or IV q6hr (over at least 2min); 
- w/ active ulcer: 300 mg PO qid w/ meals & hrs: 400mg bid or 800mg qhs; 
- chronic: 400 mg or 800 mg PO qhs; try after or w/ food or after retiring; 
- w/ Renal Failure/Elderly: 300mg IV bid; Cimetidine: Interactions and Toxicities: 
- Cimedtidine (& Ranitidine), inhibit the hepatic P-450 cytochrome system

- May cause increased Blood Levels of: 
- WARFARIN type anticoagulants 
- theophylline 
- Phenytoin

- LIDOCAINE 
- Propranolol

- metoprolol (Class II) 
- Diazepam 
- Chlordiazepoxide 
- Will interact w/ Digoxin, 
* side effects: 
- intersitial nephritis, bone marrow dyscrasias, coma, severe hepatitis, 
- these are considered to be rare; 
* cimetidine is best avoided in pts w/ hepatic dz, jaundice 

Review Article: Drug Therapy -- Histamine 2-Receptor Antagonists -- Standard Therapy for Acid-Peptic Diseases