Cimetidine


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Benign gastric and duodenal ulceration 800 mg daily at bedtime or 400 mg bid for at least 4 wk (duodenal ulcer), 6 wk (gastric ulcer) and 8 wk (NSAID-associated ulcer). Maintenance: 400 mg daily at bedtime or bid. GERD 400 mg 4 times/day or 800 mg bid for 4-12 wk. Zollinger-Ellison syndrome 300 or 400 mg 4 times/day. Prophylaxis of GI haemorrhage from stress ulceration 200-400 mg 4-6 hrly. Prophylaxis of acid aspiration during general anaesth 400 mg given 90-120 min before induction of anaesth or at the start of labour. Dose up 400 mg may be repeated 4 hrly if necessary. Max daily dose: 2.4 g. Non-ulcer dyspepsia Max: 800 mg/day in divided doses. Short bowel syndrome Initial: 400 mg bid, adjusted according to response. Pancreatic insufficiency 800-1600 mg/day in 4 divided doses. IV Benign gastric and duodenal ulceration; Zollinger-Ellison syndrome 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.
Dosage Details
Intravenous
Benign gastric and duodenal ulceration, 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.

Oral
Prophylaxis of gastrointestinal haemorrhage from stress ulceration
Adult: 200-400 mg 4-6 hrly.

Oral
Benign gastric and duodenal ulceration
Adult: 800 mg daily at bedtime or 400 mg bid for at least 4 wk for duodenal ulcers, 6 wk for gastric ulcers and 8 wk for NSAID-associated ulcers. May increase to 400 mg 4 times daily if necessary. Maintenance: 400 mg daily at bedtime or bid.

Oral
Pancreatic insufficiency
Adult: 800-1600 mg/day in 4 divided doses, taken 60-90 min before meals.

Oral
Non-ulcer dyspepsia
Adult: Max: 800 mg/day in divided doses.

Oral
Zollinger-Ellison syndrome
Adult: 300 or 400 mg 4 times daily, increase dose if necessary.

Oral
Gastro-oesophageal reflux disease
Adult: 400 mg 4 times daily or 800 mg bid for 4-12 wk.

Oral
Prophylaxis of acid aspiration during general anaesthesia
Adult: 400 mg given 90-120 minutes before induction of anaesth or at the start of labour. Dose up 400 mg may be repeated 4 hourly if necessary. Max daily dose: 2.4 g.

Oral
Short bowel syndrome
Adult: Initially, 400 mg bid, adjusted according to response.
Renal Impairment
Oral:
CrCl Dosage
0-15 200 mg bid.
16-30 200 mg tid.
31-50 200 mg 4 times daily.
Intravenous:
Severe: 300 mg 12 hrly.
Administration
Should be taken with food.
Reconstitution
Cimetidine 300 mg should be diluted to a total of 20 mL (IV inj) and at least 50 mL (intermittent IV infusion) w/ either NaCl 0.9% inj, glucose 5% or 10%, or lactated Ringer's soln.
Special Precautions
History of peptic ulcer. Increased risk of developing community-acquired pneumonia in the elderly, patients w/ chronic lung disease, DM, or the immunocompromised. Increased possibility of a hyperinfection caused by Strongyloides stercoralis in immunocompromised patients. Possibility of malignancy should be excluded prior to therapy as the drug may mask symptoms and delay diagnosis of gastric malignancy. Avoid rapid IV inj. Renal and hepatic impairment. Pregnancy and lactation.
Adverse Reactions
Diarrhoea, other GI disturbances, dizziness, headache, tiredness, myalgia, arthralgia, rashes, altered LFTs, reversible confusional states. Rarely, hypersensitivity reactions and fever, reversible alopecia, blood disorders (e.g. agranulocytosis, leucopenia, and thrombocytopenia), acute pancreatitis, interstitial nephritis, hallucinations and depression, CV disorders (e.g. bradycardia, tachycardia, heart block), transient hypotension, gynaecomastia and impotence.
Potentially Fatal: Rarely, hepatotoxicity, cardiac arrest and arrhythmias due to rapid IV inj.
IV/Parenteral/PO: B
Patient Counseling Information
May impair ability to drive, operate machinery and perform hazardous tasks requiring mental alertness.
MonitoringParameters
Monitor CBC, gastric pH, occult blood w/ GI bleeding and renal function.
Overdosage
Symptoms: Dizziness, bradycardia, CNS depression, vomiting. Management: Induce vomiting and/or gastric lavage, followed by symptomatic and supportive treatment.
Drug 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).
Food Interaction
Food delays the rate and slightly decreases extent of absorption. May enhance gastric mucosal irritation w/ alcohol.
Action
Description: 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.
Onset: 1 hr.
Duration: 4-5 hr.
Pharmacokinetics:
Absorption: Readily absorbed from the GI tract. Food delays the rate and slightly decreases extent of absorption. Bioavailability: Approx 60-70%. Time to peak plasma concentration: Approx 1-3 hr.
Distribution: Widely distributed; enters breast milk, crosses the placental barrier. Volume of distribution: Approx 1 L/kg. Plasma protein binding: Approx 20%.
Metabolism: Partially hepatic, converted to sulfoxide and hydroxymethylcimetidine.
Excretion: Via urine (oral: approx 50%, IV: 75%) as unchanged drug. Elimination half-life: Approx 2 hr.
Storage
Store between 16-30°C. Protect from light.
References
Anon. Cimetidine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 16/01/2014.

Buckingham R (ed). Cimetidine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 16/01/2014.

Cimetidine Inj (Hosipra, Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 16/01/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Cimetidine. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 16/01/2014.

Disclaimer: This information is independently developed by MIMS based on Cimetidine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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