PRAZEPAM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PRAZEPAM (PRAZEPAM).
Prazepam is a benzodiazepine that potentiates gamma-aminobutyric acid (GABA) activity at GABA-A receptors, leading to increased chloride ion influx, neuronal hyperpolarization, and central nervous system depression.
| Metabolism | Hepatic metabolism primarily via CYP3A4 to active metabolites including desmethyldiazepam and oxazepam. |
| Excretion | Primarily renal (as conjugated metabolites, mainly oxazepam glucuronide): ~95%; fecal: ~5%. |
| Half-life | Terminal elimination half-life: 36-200 hours (mean ~75 hours). Long half-life leads to accumulation with repeated dosing and prolonged sedation, especially in elderly or hepatic impairment. |
| Protein binding | ~95-98% bound to serum albumin. |
| Volume of Distribution | 0.8-1.5 L/kg. Large Vd indicates extensive tissue distribution, particularly adipose tissue, contributing to slow elimination. |
| Bioavailability | Oral: ~100% (well absorbed); IM: ~80% (erratic absorption, not recommended). |
| Onset of Action | Oral: 30-60 minutes; peak plasma levels at 2-6 hours. |
| Duration of Action | 12-24 hours (single dose); extended with chronic dosing due to long half-life and active metabolites. Clinical effects may persist >24 hours. |
10-30 mg orally 3-4 times daily; maximum daily dose 60 mg.
| Dosage form | CAPSULE |
| Renal impairment | With CrCl 30-50 mL/min: reduce dose by 25% or extend interval to 12-24 hours. With CrCl <30 mL/min: avoid use or reduce dose by 50% and monitor closely. |
| Liver impairment | Child-Pugh A: no adjustment needed. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use. |
| Pediatric use | Weight-based dosing: 0.2-0.4 mg/kg/day divided every 6-12 hours; maximum 0.6 mg/kg/day. Not recommended for children under 6 months. |
| Geriatric use | Start at lowest effective dose (2.5-5 mg/day) and titrate slowly; maximum 20 mg/day. Avoid in elderly with renal impairment or hepatic dysfunction. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PRAZEPAM (PRAZEPAM).
| Breastfeeding | Prazepam excreted in breast milk; M/P ratio unknown but expected similar to other benzodiazepines (e.g., diazepam M/P ~0.4). May cause sedation and poor feeding in infant. Avoid use during breastfeeding. |
| Teratogenic Risk | First trimester: Increased risk of oral clefts (odds ratio 1.79). Second and third trimesters: Risk of floppy infant syndrome, neonatal withdrawal, and respiratory depression. Avoid in pregnant women unless absolutely necessary. |
| Fetal Monitoring |
■ FDA Black Box Warning
Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients for whom alternative treatment options are inadequate.
| Serious Effects |
Hypersensitivity to prazepam or other benzodiazepines; narrow-angle glaucoma; severe respiratory insufficiency; severe hepatic impairment; concurrent use with ketoconazole or itraconazole.
| Precautions | Risk of dependence and withdrawal; amnesia; paradoxical reactions; CNS depressant effects; caution in patients with hepatic impairment, respiratory insufficiency, or history of substance abuse. |
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| Monitor maternal sedation, respiratory rate, and blood pressure. Fetal monitoring for heart rate variability and signs of withdrawal post-delivery. In neonates, monitor for floppy infant syndrome, sedation, and respiratory depression. |
| Fertility Effects | Benzodiazepines may cause menstrual irregularities and ovulatory dysfunction due to CNS depression and hormonal interactions. Effects on male fertility not well studied, but may impair libido and erectile function. |