TRANXENE SD
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRANXENE SD (TRANXENE SD).
Benzodiazepine that enhances GABA-A receptor activity by increasing the frequency of chloride channel opening, leading to neuronal inhibition.
| Metabolism | Hepatic via conjugation and oxidative metabolism; primary metabolite is desmethyldiazepam (active); CYP450 involvement (CYP3A4 and CYP2C19). |
| Excretion | Renal excretion of conjugated metabolites, with less than 1% unchanged drug; approximately 30% excreted in feces via biliary elimination. |
| Half-life | Terminal elimination half-life of nordazepam (active metabolite) is 30–100 hours (mean 50 hours); clorazepate itself has a short half-life (~2 hours) due to rapid conversion. |
| Protein binding | 97–98% bound to albumin; nordazepam is highly protein-bound. |
| Volume of Distribution | 0.9–1.4 L/kg for clorazepate; nordazepam Vd approximately 0.8–1.2 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: 100% (prodrug fully converted); no parenteral formulation. |
| Onset of Action | Oral: 1–2 hours for anxiolytic effect; peak plasma concentrations of nordazepam at 1–2 hours after oral dose. |
| Duration of Action | 12–24 hours for anxiolytic effect; sustained action due to long-lived active metabolite nordazepam. |
| Molecular Weight | 242.28 |
Oral: 11.25-22.5 mg once daily (sustained-release formulation).
| Dosage form | TABLET |
| Renal impairment | GFR <10 mL/min: Reduce dose by 25-50% and consider avoidance due to accumulation of active metabolites. |
| Liver impairment | Child-Pugh Class B or C: Reduce dose by 50% or avoid use; monitor for excessive sedation. |
| Pediatric use | Not recommended for patients <18 years due to lack of safety and efficacy data. |
| Geriatric use | Reduce initial dose by 50% (e.g., 11.25 mg once daily or less), titrate slowly, and monitor for falls and cognitive impairment. |
| 1st trimester | Avoid due to risk of congenital malformations, especially during organogenesis. Use only if benefit outweighs risk. |
| 2nd trimester | Limited data; consider risk of fetal benzodiazepine exposure. Use only if clearly needed. |
| 3rd trimester | Avoid near term; risk of neonatal withdrawal, hypotonia, respiratory depression, and feeding difficulties. |
Clinical note
Comprehensive clinical and safety monograph for TRANXENE SD (TRANXENE SD).
| Placental transfer | Crosses placenta by passive diffusion. Cord plasma levels are similar to maternal levels, indicating significant transfer. |
| Breastfeeding | Excreted into breast milk in low levels. Monitor infant for sedation, poor feeding, and weight loss. Use lowest effective dose for shortest duration. |
■ FDA Black Box Warning
Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death.
| Serious Effects |
Hypersensitivity to clorazepate or any benzodiazepineAcute narrow-angle glaucomaSevere hepatic impairment
| Precautions | Risk of abuse, misuse, and addiction, Dependence and withdrawal reactions, CNS depressant effects (impairment of driving/operating machinery), Respiratory depression (especially with opioids), Glaucoma (narrow-angle) use cautiously, Suicidal ideation (pre-existing depression) |
| Food/Dietary | Food may delay but does not significantly reduce absorption. Avoid grapefruit juice as it may inhibit CYP3A4, increasing nordazepam levels. Avoid alcohol completely. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) – limited data suggest potential risk, but benefit may outweigh risk in some situations. |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations (oral clefts) reported with benzodiazepine use; data specifically for clorazepate limited but class effect assumed. Second/third trimester: Exposure may cause fetal CNS depression, hypotonia, respiratory depression, and withdrawal symptoms (e.g., jitteriness, hypertonia) in neonates. |
| Fetal Monitoring | Maternal: Assess for sedation, ataxia, respiratory depression; monitor liver function and complete blood counts periodically. Fetal/neonatal: Ultrasound for congenital anomalies if first-trimester exposure; neonatal assessment for withdrawal symptoms (e.g., Flanagan scale) and respiratory depression after delivery. |
| Fertility Effects | Data limited. Chronic benzodiazepine use may alter hypothalamic-pituitary-gonadal axis, potentially affecting ovulation or spermatogenesis; specific effects of clorazepate on fertility not established. May cause menstrual irregularities or decreased libido. |
| Clinical Pearls | TRANXENE SD (clorazepate dipotassium) is a long-acting benzodiazepine with a slow onset, making it less suitable for acute panic but effective for generalized anxiety. Its active metabolite, nordazepam, has a half-life of 40-100 hours, allowing once-daily dosing. Monitor for accumulation in elderly or hepatic impairment. Use with caution in patients with a history of substance abuse due to dependence risk. |
| Patient Advice | Take exactly as prescribed; do not increase dose or frequency without consulting your doctor. · Do not stop abruptly; reduce dose gradually to avoid withdrawal symptoms (e.g., anxiety, insomnia, seizures). · Avoid alcohol and other CNS depressants (e.g., opioids, sedatives) as they increase sedation and respiratory depression risk. · May cause drowsiness or dizziness; avoid driving or operating heavy machinery until you know how the drug affects you. · Report any unusual changes in mood, thoughts, or behavior (e.g., depression, suicidal thoughts). · Use effective contraception if of childbearing potential due to fetal harm risk; notify prescriber if pregnant or breastfeeding. |