RAZADYNE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RAZADYNE (RAZADYNE).
Galantamine is a reversible competitive acetylcholinesterase inhibitor and an allosteric modulator of nicotinic acetylcholine receptors, enhancing cholinergic function in the central nervous system.
| Metabolism | Primarily hepatic via CYP2D6 and CYP3A4; also undergoes glucuronidation. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 20-25% of the dose; the remainder is metabolized by the liver and excreted as metabolites in urine (about 95% total) and feces (about 5%). |
| Half-life | Terminal elimination half-life is approximately 7-8 hours in healthy adults, allowing twice-daily dosing; unchanged in mild to moderate hepatic impairment but prolonged in severe hepatic impairment. |
| Protein binding | 18-40% bound to plasma proteins, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is approximately 1.8-2.8 L/kg, indicating extensive tissue distribution beyond plasma volume. |
| Bioavailability | Oral immediate-release: 100% relative to intravenous; oral extended-release: 96-100% relative to immediate-release; food delays absorption but does not affect extent. |
| Onset of Action | Oral immediate-release: 30-60 minutes; oral extended-release: 4-6 hours (steady-state reached in 1-2 weeks). |
| Duration of Action | Oral immediate-release: 8-12 hours; oral extended-release: 24 hours with once-daily dosing; effects are dose-dependent and sustained with regular dosing. |
Initial dose 8 mg/day PO (4 mg twice daily) for 4 weeks; increase to 16 mg/day (8 mg twice daily) for at least 4 weeks; maintenance 16-24 mg/day (12 mg twice daily). Extended-release: initial 8 mg PO once daily; after 4 weeks increase to 16 mg once daily; if tolerated, may increase to 24 mg once daily.
| Dosage form | TABLET |
| Renal impairment | GFR 50-80 mL/min: no adjustment. GFR 30-50 mL/min: maximum dose 16 mg/day. GFR <30 mL/min: not recommended. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: maximum dose 16 mg/day. Child-Pugh C: not recommended. |
| Pediatric use | Not established for pediatric use; no weight-based guidelines available. |
| Geriatric use | No specific dose adjustment; titrate slowly due to increased sensitivity to cholinergic effects. Monitor for bradycardia and gastrointestinal effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for RAZADYNE (RAZADYNE).
| Breastfeeding | Excretion into breast milk unknown; caution advised. M/P ratio not established. |
| Teratogenic Risk | Pregnancy Category B. Animal studies showed no fetal harm, but no adequate human studies. Use only if clearly needed. |
| Fetal Monitoring | Monitor for gastrointestinal effects and bradycardia in mother; fetal heart rate monitoring if late pregnancy. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to galantamine or any component of the formulation, severe hepatic impairment (Child-Pugh score >9), and concomitant use with other cholinomimetics.
| Precautions | Serious skin reactions (e.g., Stevens-Johnson syndrome), bradycardia, heart block, increased risk of gastrointestinal bleeding, worsening of Parkinsonian symptoms, and increased mortality in patients with mild cognitive impairment. |
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| Fertility Effects | No data on human fertility; animal studies showed no impairment. |