CHLORDIAZEPOXIDE HYDROCHLORIDE AND CLIDINIUM BROMIDE
Clinical safety rating: avoid
CNS depressants including alcohol and opioids increase sedation risk Abrupt discontinuation can cause withdrawal symptoms.
Chlordiazepoxide is a benzodiazepine that enhances GABA-A receptor activity, increasing chloride ion influx and causing CNS depression. Clidinium bromide is an anticholinergic that blocks muscarinic acetylcholine receptors, reducing GI motility and secretions.
| Metabolism | Chlordiazepoxide is metabolized by hepatic CYP450 enzymes (primarily CYP3A4) to active metabolites (desmethylchlordiazepoxide, demoxepam, nordazepam, oxazepam). Clidinium is not extensively metabolized. |
| Excretion | Chlordiazepoxide is extensively metabolized in the liver to active metabolites (e.g., desmethylchlordiazepoxide, demoxepam). Renal excretion accounts for approximately 20% of unchanged drug; the remainder is excreted as metabolites in urine (80-90%) and feces (10-20%). Clidinium is excreted primarily unchanged in urine (75%) and feces (25%). |
| Half-life | Chlordiazepoxide has a terminal elimination half-life of 5-30 hours (mean ~24 hours) in adults; its active metabolite desmethylchlordiazepoxide has a half-life of 10-30 hours. Accumulation occurs with repeated dosing. In elderly or hepatic impairment, half-life may be prolonged significantly. Clidinium has a half-life of 10-12 hours. |
| Protein binding | Chlordiazepoxide is 96-98% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein). Clidinium is approximately 50% bound to plasma proteins. |
| Volume of Distribution | Chlordiazepoxide: apparent Vd of 0.3-0.6 L/kg (approximately 20-40 L in adults), indicating extensive tissue distribution. Clidinium: Vd approximately 1-2 L/kg, reflecting distribution into peripheral tissues. |
| Bioavailability | Oral bioavailability of chlordiazepoxide is 80-90% (high, due to complete absorption but first-pass metabolism). Clidinium has poor oral bioavailability (~10-20%) due to extensive first-pass metabolism and incomplete absorption; the combination product is formulated to deliver both drugs. |
| Onset of Action | Oral: 15-45 minutes for chlordiazepoxide's anxiolytic effect; clidinium's anticholinergic effect begins within 1 hour. Peak plasma concentrations occur at 1-4 hours. |
| Duration of Action | Anxiolytic and sedative effects of chlordiazepoxide last 4-8 hours after a single dose, but active metabolites prolong clinical duration. Anticholinergic effects of clidinium persist 6-8 hours. Steady-state is reached within 3-7 days. |
| Molecular Weight | Chlordiazepoxide hydrochloride: 336.2 g/mol; Clidinium bromide: 432.2 g/mol |
Each tablet contains chlordiazepoxide HCl 5 mg and clidinium bromide 2.5 mg. Typical adult dose: 1-2 tablets orally 3-4 times daily before meals and at bedtime. Max 8 tablets daily.
| Dosage form | CAPSULE |
| Renal impairment | GFR 50-80 mL/min: No adjustment. GFR 10-50 mL/min: Administer 50-75% of normal dose. GFR <10 mL/min: Avoid use due to risk of accumulation. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50%. Child-Pugh C: Avoid use. |
| Pediatric use | Not recommended for children under 6 years. For children 6-12 years: chlordiazepoxide 5 mg and clidinium 2.5 mg orally 2-4 times daily, adjust based on weight (0.5 mg/kg/day chlordiazepoxide equivalent divided into 3-4 doses). |
| Geriatric use | Initially 1 tablet (5 mg/2.5 mg) orally 1-2 times daily, titrate slowly. Avoid doses ≥ 4 tablets daily due to increased sensitivity to CNS effects and anticholinergic side effects. |
| 1st trimester | Use is contraindicated in the first trimester due to increased risk of congenital malformations, particularly cleft lip and/or cleft palate. Studies suggest a twofold to threefold increase in risk with first-trimester exposure to benzodiazepines. Additionally, clidinium bromide, an anticholinergic, may cause neonatal anticholinergic effects. |
| 2nd trimester | Use in the second trimester is associated with persistent risks of developmental abnormalities, though less pronounced than first trimester. The anticholinergic component may contribute to fetal tachycardia and decreased gastrointestinal motility. Should only be used if clearly needed and no safer alternatives exist. |
| 3rd trimester | Use during the third trimester may cause neonatal withdrawal syndrome (irritability, hypertonia, feeding difficulties) and floppy infant syndrome (hypotonia, lethargy, respiratory depression) due to benzodiazepine exposure. Clidinium bromide may exacerbate anticholinergic effects in the neonate. Avoid use during labor and delivery. |
Clinical note
CNS depressants including alcohol and opioids increase sedation risk Abrupt discontinuation can cause withdrawal symptoms.
| FDA category | Positive |
■ FDA Black Box Warning
None
| Common Effects | alcohol withdrawal |
| Serious Effects |
Severe hepatic impairmentNarrow-angle glaucomaMyasthenia gravisKnown hypersensitivity to chlordiazepoxide, clidinium, or any benzodiazepineFirst trimester of pregnancy (due to teratogenic risk)Concurrent use with protease inhibitors (e.g., atazanavir, ritonavir) due to risk of excessive sedation and respiratory depressionSevere respiratory insufficiency (unless on mechanical ventilation)
| Precautions | Risk of dependence, tolerance, and withdrawal with prolonged use of chlordiazepoxide, May impair cognitive and motor function; avoid driving or operating machinery, Concomitant use with opioids may cause profound sedation, respiratory depression, coma, and death, Use cautiously in elderly, debilitated patients, and those with hepatic or renal impairment, Anticholinergic effects of clidinium may cause urinary retention, constipation, blurred vision, and heat intolerance |
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| Placental transfer | Both components cross the placenta. Chlordiazepoxide and its active metabolite, nordazepam, readily cross the placental barrier, with fetal serum concentrations reaching approximately 50-100% of maternal levels. Clidinium bromide is likely to cross the placenta due to its low molecular weight, though specific data are lacking. |
| Breastfeeding | Chlordiazepoxide is excreted into breast milk in low to moderate amounts. The estimated infant dose is about 2-4% of the weight-adjusted maternal dose, which is generally considered low but may cause sedation and feeding difficulties in breastfed infants. Clidinium bromide is poorly absorbed orally and its excretion into breast milk is unknown; it may have anticholinergic effects such as decreased milk production and infant gastrointestinal disturbances. Due to the combination's risks, alternative agents are preferred during breastfeeding. If used, monitor infant for sedation, poor feeding, and weight gain. |
| Lactation Rating | L3 - Probably Compatible (limited data, use with caution) |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations (e.g., cleft lip/palate, cardiac defects) based on benzodiazepine data. Second and third trimesters: Risk of hypotonia, respiratory depression, withdrawal symptoms (e.g., irritability, hypertonia) in neonates after chronic exposure. Avoid use during pregnancy, especially first trimester. |
| Fetal Monitoring | Maternal: liver function tests, CBC, and renal function periodically. Fetal: ultrasound for growth and anatomy if used during first trimester. Neonatal: Apgar scores, respiratory status, and withdrawal signs (e.g., modified Finnegan scoring) for 24–48 hours after delivery if chronic maternal use. |
| Fertility Effects | No specific human data for chlordiazepoxide/clidinium. Benzodiazepines may cause menstrual irregularity, anovulation, or decreased libido; effects on fertility are uncertain. Clidinium is anticholinergic with unknown reproductive impact. |
| Food/Dietary |
| Avoid alcohol and products containing alcohol (e.g., some mouthwashes, cough syrups) as they potentiate CNS depression. Grapefruit juice may theoretically increase benzodiazepine absorption but is not a major concern with chlordiazepoxide. No significant food interactions are reported for clidinium; however, high-fiber meals may reduce gastrointestinal motility and anticholinergic absorption. Maintain adequate fluid intake to counteract anticholinergic-induced constipation. |
| Clinical Pearls | Chlordiazepoxide/clidinium (Librax) combines a benzodiazepine anxiolytic with an anticholinergic/antispasmodic. It is primarily used for irritable bowel syndrome (IBS) and peptic ulcer disease. Due to the benzodiazepine component, avoid use in patients with severe hepatic impairment, narrow-angle glaucoma, or concurrent CNS depressants. The anticholinergic component may exacerbate urinary retention, constipation, and hyperthermia. Elderly patients are at increased risk for falls, cognitive impairment, and anticholinergic side effects; consider deprescribing. Monitor for paradoxical reactions and dependence with prolonged use. |
| Patient Advice | This medication may cause drowsiness or dizziness; avoid driving or operating heavy machinery until you know how it affects you. · Do not drink alcohol while taking this medication; it can increase the sedative effects. · Report any signs of an allergic reaction, such as rash, itching, or swelling, especially of the face or throat. · Avoid use in combination with other sedatives, muscle relaxants, or opioids unless directed by your doctor. · If you become pregnant or plan to become pregnant, consult your doctor immediately; use during pregnancy may harm the baby. · Do not stop taking this medication abruptly; it may cause withdrawal symptoms such as anxiety, insomnia, or seizures. · Notify your doctor if you develop blurred vision, difficulty urinating, constipation, or confusion. · Take this medication exactly as prescribed; do not increase the dose or frequency without medical advice. |