AXID
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AXID (AXID).
Competitive, reversible inhibition of histamine at H2-receptors on gastric parietal cells, reducing gastric acid secretion by blocking the H2-receptor-mediated activation of adenylate cyclase and subsequent cAMP production.
| Metabolism | Hepatic metabolism via N-oxidation, S-oxidation, and N-demethylation; partially metabolized by cytochrome P450 (CYP) enzymes (CYP1A2, CYP3A4) but less extensive than cimetidine; also undergoes conjugation and renal elimination; approximately 30% excreted unchanged in urine. |
| Excretion | Renal (60% unchanged), biliary (30%), fecal (<10%) |
| Half-life | 1.5-2.5 hours (prolonged in renal impairment: up to 4-5 hours if CrCl <20 mL/min) |
| Protein binding | 25-35% (primarily albumin) |
| Volume of Distribution | 0.8-1.2 L/kg (suggests distribution into total body water) |
| Bioavailability | Oral: 85-95% (no significant food effect) |
| Onset of Action | Oral: 30-60 minutes; IV: 15-30 minutes |
| Duration of Action | 6-8 hours (dose-dependent; single oral dose suppresses acid for up to 8 hours) |
| Action Class | H2 Receptor Blocker |
300 mg orally once daily at bedtime or 150 mg orally twice daily. Max 300 mg/day.
| Dosage form | SOLUTION |
| Renal impairment | CrCl 20-50 mL/min: 150 mg once daily. CrCl <20 mL/min: 150 mg every other day. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment. Not studied in severe hepatic impairment. |
| Pediatric use | For patients ≥12 years: 150 mg orally twice daily or 300 mg once daily. Safety and efficacy in children <12 not established. |
| Geriatric use | No specific adjustment; consider age-related renal function decline and adjust per renal guidelines. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AXID (AXID).
| Breastfeeding | Excreted in human milk in small amounts (M/P ratio not established). Use caution; potential for adverse effects (e.g., H2-receptor antagonist effects). American Academy of Pediatrics considers compatible with breastfeeding. |
| Teratogenic Risk | Pregnancy Category B. Animal studies (rats, rabbits) at up to 300 mg/kg/day (60 times human dose) showed no fetal harm. No adequate human studies. First trimester: no documented increased risk; second/third trimester: limited data, consider risk-benefit. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to nizatidine or any component of the formulation; history of acute porphyria (may precipitate attacks)
| Precautions | Renal impairment (dose reduction recommended; CrCl <50 mL/min), hepatic impairment (possible accumulation), elderly patients (increased risk of confusional states), gastric malignancy (symptomatic response may mask underlying gastric cancer), rapid IV administration (rare bradycardia; avoid bolus injection), Cross-sensitivity with other H2 antagonists, potential for vitamin B12 deficiency with long-term use |
| Food/Dietary | Take with food to reduce GI upset; avoid high-fat meals which may delay absorption. No specific food restrictions. |
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| Monitor maternal symptoms of peptic ulcer disease or GERD. No specific fetal monitoring required unless maternal condition warrants. Assess for adverse effects in breastfeeding infants. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies show no impairment at high doses. |
| Clinical Pearls | AXID (nizatidine) is an H2 receptor antagonist used for GERD and peptic ulcer disease. It does not inhibit CYP450 enzymes, minimizing drug interactions. Monitor renal function; dose adjustment required for CrCl <50 mL/min. Avoid in patients with hypersensitivity to other H2 blockers. |
| Patient Advice | Take exactly as prescribed, usually once daily at bedtime for duodenal ulcer or twice daily for GERD. · Notify your doctor if you experience confusion, hallucinations, or irregular heartbeat. · Avoid alcohol and NSAIDs as they can worsen stomach irritation. · Complete full course even if symptoms improve. |