Cim (ANTASID)

Uses

Benign gastric and duodenal ulceration, GERD, Zollinger-Ellison syndrome, Prophylaxis of GI haemorrhage from stress ulceration, Prophylaxis of acid aspiration during general anesthesia, Non-ulcer dyspepsia, Prophylaxis of nocturnal heartburn, Short bowel syndrome, Pancreatic insufficiency, Benign gastric and duodenal ulceration, Zollinger-Ellison syndrome Intermittent infusion

Cim (ANTASID) is also used to associated treatment for these conditions: Cystic Fibrosis (CF), Gastric hypersecretion, Gastro-esophageal Reflux Disease (GERD), Gastrointestinal Symptoms, Heartburn, NSAID Associated Gastric Ulcers, Active Duodenal ulcer, Benign gastric ulcers, Recurrent Ulcers, Duodenal and Gastric

How Cim (ANTASID) works

Cim (ANTASID) binds to an H₂-receptor located on the basolateral membrane of the gastric parietal cell, blocking histamine effects. This competitive inhibition results in reduced gastric acid secretion and a reduction in gastric volume and acidity.

Dosage

Cim (ANTASID) dosage

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 90-120 min before induction of anaesth up to 400 mg 4 hrly if needed.

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

Prophylaxis of nocturnal heartburn: 100 mg at bedtime.

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.

Should be taken with food.

Side Effects

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.

Toxicity

In the rare event of cimetidine overdose, it is vital to maintain the airway and cardiovascular status. The patient should be closely monitored and provided with symptomatic and supportive treatment as needed. Interventions such as gastric lavage and administration of activated charcoal may be initiated if deemed appropriate and necessary.

Precaution

History of peptic ulcer. Increased risk of developing community-acquired pneumonia in the elderly, patients with 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.

Interaction

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 with 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

• Take with food. Food increases bioavailability. For prophylaxis of gastric symptoms, take cimetidine 30-60 minutes prior to food administration.

Cim (ANTASID) Alcohol interaction

[Minor] Concurrent use of cimetidine and ethanol may result in increased ethanol concentrations.

The mechanism appears to be due to inhibition of gastric alcohol dehydrogenase by cimetidine, leading to increased bioavailability of the alcohol and inhibition of hepatic metabolism of alcohol.

The clinical significance of this interaction is limited.

More importantly, patients requiring cimetidine for gastrointestinal disease should be counseled to avoid alcohol to prevent worsening of their disease.

The other H-2 receptor antagonists appear to have minimal effects on the concentrations of alcohol.

Cim (ANTASID) Drug Interaction

Moderate: duloxetine, duloxetineMinor: acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, cholecalciferol, cholecalciferolUnknown: aspirin, aspirin, diphenhydramine, diphenhydramine, omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, pregabalin, pregabalin, ascorbic acid, ascorbic acid, cetirizine, cetirizine

Cim (ANTASID) Disease Interaction

Major: liver disease, GI bleedingModerate: hemodialysis, renal dysfunction

Volume of Distribution

The volume of distribution of cimetidine is reported to be 1 L/kg.

Elimination Route

Two peak plasma concentrations are often observed after oral administration of cimetidine, likely as a result of discontinuous absorption in the gastrointestinal tract. In healthy patients, the absolute bioavailability of cimetidine is approximately 60%; however, the bioavailability can be as high as 70% in patients with peptic ulcer disease. Overall, rates of bioavailability are much more variable in patients with peptic ulcer disease.

Half Life

Cim (ANTASID)'s half-life is estimated to be around 2 hours.

Clearance

Cim (ANTASID)'s reported systemic clearance value is approximately 500-600 ml/min.

Elimination Route

Cim (ANTASID) is excreted primarily in the urine.

Pregnancy & Breastfeeding use

Pregnancy Category B. Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Contraindication

Cim (ANTASID) is contraindicated in any patient hypersensitive to the drug or its components.

Acute Overdose

Symptoms: Dizziness, bradycardia, CNS depression, vomiting.

Management: Induce vomiting and/or gastric lavage, followed by symptomatic and supportive treatment.

Storage Condition

Store between 16-30°C. Protect from light.

Innovators Monograph

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