Cimetidine

Indications

Cimetidine is used for: Heartburn, Dyspepsia, Peptic ulcers, Benign gastric and duodenal ulceration, Gastro-oesophageal reflux disease, Zollinger-Ellison syndrome, Pancreatic insufficiency

Adult Dose

Intravenous Benign gastric and duodenal ulceration Adult: Intermittent infusion: 300 mg 6-8 hrly infused over 15-20 min. Max: 2400 mg/day. Continuous infusion: 37.5 mg/hr (900 mg/day). A 150 mg IV loading dose may be given in patients requiring rapid elevation of gastric pH. Zollinger-Ellison syndrome Adult: Intermittent infusion: 300 mg 6-8 hrly infused over 15-20 min. Max: 2400 mg/day. Continuous infusion: 37.5 mg/hr (900 mg/day). A 150 mg IV loading dose may be given in patients requiring rapid elevation of gastric pH.

Child Dose

Renal Dose

Renal Impairment CrCl<30 mL/min 300 mg IV/IO q12hr Prevention of upper GI bleeding: 25 mg/hour continuous IV infusion

Administration

IV Preparation Solution Injections: in 5% sodium bicarbonate injection, NS, D5W, D10W or LR to a volume of 20 mL Infusions: 300 mg in 100 mL D5W IV Administration Slow direct IV injection over 5 min or more after dilution to a total of 20 mL with compatible diluent (NS), OR Intermittent IV infusion over 15 to 20 min in at least 50 mL of compatible diluent, OR Continuous IV infusion in 100 to 1000 mL of compatible diluent over 24 hr

Contra Indications

Hypersensitivity, lactation.

Precautions

Impaired renal and hepatic function. Age >50 yr; CV impairment. Pregnancy. Lactation: enters breast milk/not recommended

Pregnancy-Lactation

Interactions

Reduces absorption of dasatinib, ketoconazole, itraconazole and posaconazole. May increase serum levels of phenytoin, theophylline, lidocaine, hydroxyzine and oral anticoagulants. Absorption may be reduced by antacids. Decreased bioavailability w/ metoclopramide, sucralfate or propantheline. May potentiate the myelosuppressive effects (e.g. agranulocytosis, neutropenia) of myelosuppressive drugs (e.g. antimetabolites, alkylating agents) or therapies (e.g. radiation).

Adverse Effects

Side effects of Cimetidine : 1-10% Headache (2.1%),Dizziness (1%),Somnolence (1%),Gynecomastia (0.3-4%) Frequency Not Defined Confusion (elderly),Impotence,Diarrhea,Nausea,Vomiting

Mechanism of Action

Cimetidine competitively inhibits histamine at H2-receptors of the gastric parietal cells resulting in decreased gastric acid secretion, gastric volume and hydrogen ion concentration. It is also used in patients w/ pancreatic insufficiency to reduce the breakdown of pancreatic enzyme supplements.