SERAX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SERAX (SERAX).
SERAX (oxazepam) is a benzodiazepine that modulates GABA-A receptors, enhancing the inhibitory effect of GABA, leading to anxiolytic, sedative, and anticonvulsant effects.
| Metabolism | Primarily hepatic via glucuronide conjugation (glucuronidation) mediated by UDP-glucuronosyltransferases; not significantly metabolized by CYP450 enzymes. |
| Excretion | Primarily renal (urinary) as unchanged drug (60-80%) and metabolites (20-40%); less than 5% fecal elimination. |
| Half-life | Terminal elimination half-life is 8-15 hours (mean 12 hours) in adults; prolonged in renal impairment. |
| Protein binding | Approximately 85-95% bound to serum albumin. |
| Volume of Distribution | Vd ~0.7-1.1 L/kg (mean 0.9 L/kg), indicating extensive tissue distribution. |
| Bioavailability | Oral: 80-90%; IM: 95-100%. |
| Onset of Action | Oral: 30-60 minutes; IV: 1-3 minutes; IM: 10-15 minutes. |
| Duration of Action | Oral: 6-8 hours; IV: 3-4 hours; IM: 4-6 hours. |
| Molecular Weight | 352.43 |
| Action Class | Proteolytic Enzymes |
| Brand Substitutes | Serowel Tablet, Basebard 10mg Tablet, Serperite 10mg Tablet, Seridase 10mg Tablet, Serdase 10mg Tablet, Mucozen Forte 20mg Tablet, Exudase 20mg Tablet, Seriflam DS 20mg Tablet, Synotrip 20mg Tablet, Espidase 20mg Tablet, Zinase 20mg Tablet |
Oral: 5-10 mg twice daily; maximum 20 mg/day. Intravenous: 2-5 mg slow IV push, may repeat after 2 hours.
| Dosage form | TABLET |
| Renal impairment | GFR <30 mL/min: reduce dose by 50% or extend interval to every 12-24 hours. Not dialyzable. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use. |
| Pediatric use | Children <6 years: not recommended. 6-12 years: 1.25-2.5 mg orally 2-3 times daily; maximum 10 mg/day. |
| Geriatric use | Initial dose 2.5 mg once or twice daily; increase cautiously. Avoid use in elderly with hepatic impairment or CYP2C19 poor metabolizers. |
| 1st trimester | Risk of congenital malformations based on animal studies; human data limited. Use only if potential benefit justifies risk. |
| 2nd trimester | May be used if clearly needed; monitor maternal and fetal effects. |
| 3rd trimester | May cause adverse effects on the neonate (e.g., withdrawal, respiratory depression) if used near term. |
Clinical note
Comprehensive clinical and safety monograph for SERAX (SERAX).
| Placental transfer | Crosses placenta; detected in fetal plasma at concentrations similar to maternal levels. |
| Breastfeeding | Excreted into breast milk in small amounts; monitor infant for drowsiness, feeding difficulties, and weight gain. Consider benefits versus risks. |
| Lactation Rating |
■ FDA Black Box Warning
Concomitant use with opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required.
| Serious Effects |
Hypersensitivity to Serax or any componentAcute narrow-angle glaucomaSevere respiratory insufficiencyMyasthenia gravis
| Precautions | Risk of respiratory depression, especially when used with opioids or other CNS depressants, Dependence and withdrawal reactions, Abuse potential, Paradoxical reactions (e.g., hostility, insomnia), Impaired cognition and psychomotor function, Use with caution in hepatic impairment |
| Food/Dietary | Avoid grapefruit and grapefruit juice as they may increase oxazepam levels. Take with or without food; high-fat meals may slightly delay absorption but not significantly affect overall exposure. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Increased risk of major malformations, particularly orofacial clefts and neural tube defects, with exposure during weeks 4-10. Second and third trimesters: Risk of fetal neurobehavioral effects, including potential for neonatal withdrawal syndrome and persistent pulmonary hypertension of the newborn (PPHN). Avoid use throughout pregnancy unless absolutely necessary. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate regularly. Assess fetal growth and amniotic fluid volume via ultrasound every 4 weeks after 20 weeks. Perform nonstress test or biophysical profile weekly after 32 weeks if used chronically. Monitor neonate for signs of withdrawal (jitteriness, hypertonia, poor feeding) and respiratory depression at delivery. |
| Fertility Effects | No known impairment of fertility in humans. Animal studies show no adverse effects on reproductive function. However, chronic use may disrupt ovulatory cycles due to CNS effects. |
| Clinical Pearls | SERAX (oxazepam) is a benzodiazepine with intermediate onset and no active metabolites, making it suitable for elderly patients or those with hepatic impairment. Due to its low potential for accumulation, it is useful for intermittent anxiety. Caution with concurrent CNS depressants; withdrawal symptoms may occur upon abrupt discontinuation. |
| Patient Advice | Take exactly as prescribed; do not increase dose or duration without consulting your doctor. · Avoid alcohol and other CNS depressants while taking this medication. · Do not drive or operate heavy machinery until you know how this drug affects you. · Do not stop taking this medicine suddenly; dose should be tapered to avoid withdrawal symptoms. · Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. |