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Cautions

Contraindications

• Known hypersensitivity to cimetidine or any ingredient in the formulation.

Warnings/Precautions

General Precautions

Cardiovascular Effects

Rapid IV administration associated rarely with hypotension, cardiac arrhythmias; avoid.

Gastric Malignancy

Response to cimetidine does not preclude presence of gastric malignancy.

CNS Effects

Reversible confusional states reported, especially in geriatric (i.e., ≥50 years) and severely ill (e.g., hepatic or renal disease, organic brain syndrome) patients. Usually occurs within 2–3 days after initiating cimetidine and resolves within 3–4 days after discontinuance.

Respiratory Effects

Administration of H₂-receptor antagonists has been associated with an increased risk for developing certain infections (e.g., community-acquired pneumonia).

Specific Populations

Pregnancy

Category B.

Pregnant women should consult a clinician before using for self-medication.

Lactation

Distributed into milk. Generally, do not nurse during therapy with cimetidine.

Nursing women should consult a clinician before using for self-medication.

Pediatric Use

Safety and efficacy not established in children <16 years of age; do not use unless potential benefits outweigh risks.

Safety and efficacy for self-medication not established in children <12 years of age; do not use unless directed by a clinician.

Renal Impairment

Dosage adjustments necessary in patients with severe renal impairment. (See Renal Impairment under Dosage and Administration.)

Hepatic Impairment

Further dosage adjustments may be necessary in presence of severe renal impairment. (See Hepatic Impairment under Dosage and Administration.)

Immunocompromised Patients

Increased possibility of Strongyloides stercoralis hyperinfection with decreased gastric acidity.

Common Adverse Effects

Headache, dizziness, somnolence, diarrhea.

With ≥1 month of therapy: gynecomastia.

With IM therapy: transient pain at injection site.

Drug Interactions

Inhibits hepatic microsomal enzyme systems, decreases hepatic metabolism of some drugs. If necessary, adjust dosage of hepatically metabolized drugs when cimetidine therapy is initiated or discontinued.

Specific Drugs