ZANTAC IN PLASTIC CONTAINER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZANTAC IN PLASTIC CONTAINER (ZANTAC IN PLASTIC CONTAINER).
Competitive antagonist of histamine H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion.
| Metabolism | Primarily hepatic metabolism via N-oxidation, N-dealkylation, and S-oxidation; minimal first-pass metabolism; cytochrome P450 involvement not significant. |
| Excretion | Renal: 70% (unchanged drug); Hepatic metabolism: 30% (minor N-oxide, S-oxide, and desmethyl metabolites); Biliary/fecal: negligible. |
| Half-life | Terminal elimination half-life: 2.5–3 hours; prolonged to 4–5 hours in elderly or moderate renal impairment; accumulates in severe renal failure (CrCl <10 mL/min). |
| Protein binding | 15% bound, primarily to albumin. |
| Volume of Distribution | Approximately 1.2–1.4 L/kg; distributes widely into tissues, including breast milk and placenta. |
| Bioavailability | Oral: 50% (first-pass metabolism); IM: 90–100%. |
| Onset of Action | Oral: 30 minutes; IV: within minutes; IM: 10–15 minutes. |
| Duration of Action | Oral: 4–8 hours (single dose), 10–12 hours with repeated dosing; IV: 4–6 hours; IM: 6–8 hours. |
150 mg orally twice daily or 50 mg intravenously every 6 to 8 hours.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl <50 mL/min: reduce dose to 150 mg orally once daily or 50 mg intravenously every 12 to 24 hours. |
| Liver impairment | No specific adjustment recommended for hepatic impairment; use with caution. |
| Pediatric use | 1 month to 16 years: 2 to 4 mg/kg orally twice daily; maximum 150 mg twice daily. IV: 2 to 4 mg/kg/day divided every 6 to 8 hours. |
| Geriatric use | Consider reduced starting dose due to increased risk of confusion and adverse effects; adjust based on renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZANTAC IN PLASTIC CONTAINER (ZANTAC IN PLASTIC CONTAINER).
| Breastfeeding | Excreted in human breast milk; M/P ratio approximately 0.5. Use with caution due to potential for adverse effects in nursing infant (e.g., CNS stimulation). |
| Teratogenic Risk | Pregnancy category B. Animal studies show no fetal harm. No adequate human studies in first trimester. Second and third trimester: no evidence of risk from postmarketing surveillance. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to ranitidine or any component of the formulation","Acute porphyria"]
| Precautions | ["May cause confusion, delirium, hallucinations, especially in elderly or severely ill patients","Use caution in patients with hepatic or renal impairment (reduce dose)","May increase risk of pneumonia in hospitalized patients","May cause vitamin B12 deficiency with prolonged use","Rapid IV administration may cause bradycardia","Use caution in acute porphyria"] |
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| No specific monitoring required beyond standard prenatal care. Monitor for maternal adverse effects (headache, dizziness, GI symptoms). |
| Fertility Effects | No known adverse effects on fertility in animal or human studies. |