What is Librax (chlordiazepoxide/clidinium bromide)?

What is Librax?

Librax is a fixed-dose combination prescription medication containing chlordiazepoxide (a benzodiazepine) and clidinium bromide (an anticholinergic), FDA-approved for adjunctive treatment of peptic ulcers, irritable bowel syndrome (IBS), and acute enterocolitis. 1

Mechanism of Action

The combination provides synergistic effects through dual mechanisms:

• Chlordiazepoxide acts centrally to suppress both sympathetic and parasympathetic autonomic input to the gastrointestinal tract, providing anxiolytic effects that reduce stress-related gastric symptoms 2
• Clidinium bromide provides peripheral anticholinergic blockade, directly reducing gastric acid secretion and intestinal motility 2
• The combination produces a nearly 5-fold greater protective effect against stress-induced gastric mucosal erosion compared to clidinium alone, and is 3 times more potent than predicted by simple additivity of individual drug effects 2

FDA-Approved Indications

Librax is indicated as adjunctive therapy for: 1

• Peptic ulcer disease
• Irritable bowel syndrome (IBS)
• Acute enterocolitis (inflammation of the colon)

Clinical Evidence

A 2020 randomized controlled trial demonstrated that clidinium/chlordiazepoxide as add-on therapy to proton pump inhibitors (PPIs) achieved a 41% response rate versus 5% with placebo in refractory functional dyspepsia (defined as >50% reduction in symptom scores at 4 weeks). 3 The combination also significantly improved quality of life compared to placebo. 3

Dosing and Administration

• Standard formulation: Chlordiazepoxide 5 mg combined with clidinium bromide 2.5 mg (2:1 ratio) 1
• Take exactly as prescribed by your healthcare provider 1
• Do not suddenly discontinue due to risk of severe withdrawal reactions 1

Critical Safety Warnings

Black Box Warnings

Librax carries serious risks due to its benzodiazepine component: 1

• CNS depression: Combining with opioids, alcohol, or other CNS depressants can cause severe drowsiness, respiratory depression, coma, and death 1
• Abuse and addiction potential: Risk of abuse, misuse, and addiction even when taken as prescribed; serious side effects including delirium, paranoia, suicidal thoughts, seizures, and difficulty breathing have occurred 1
• Physical dependence and withdrawal: Sudden discontinuation can cause life-threatening withdrawal including seizures, severe mental changes, hallucinations, suicidal thoughts, and symptoms lasting weeks to over 12 months 1

Absolute Contraindications

Do not use Librax if you have: 1

• Glaucoma
• Enlarged prostate (benign prostatic hyperplasia)
• Bladder outlet obstruction causing urinary retention
• Known allergy to chlordiazepoxide or clidinium bromide

Special Population Considerations

Elderly patients require particular caution: 4

• Elderly patients are significantly more sensitive to benzodiazepine sedative effects and require lower doses 5
• The American Geriatrics Society Beers Criteria recommends avoiding benzodiazepines in patients with dementia due to increased risk of cognitive decline, delirium, and falls 4
• Maximum duration should be 4 weeks; use beyond this timeframe significantly increases risks of physical dependence, cognitive impairment, and falls 4

Pregnancy and breastfeeding: 1

• Avoid during first trimester; may harm unborn baby 1
• Passes into breast milk and may harm nursing infants; may also decrease milk production 1

Hepatic insufficiency: 6

• Chlordiazepoxide metabolism is markedly delayed in hepatic insufficiency, creating risk of "dose-stacking" where unmetabolized drug accumulates before therapeutic effect occurs 6
• This can result in delayed, profound, and prolonged sedation even after discontinuation, as the accumulated chlordiazepoxide slowly converts to its long-acting metabolite demoxepam (half-life 14-95 hours) 6, 7

Common Adverse Effects

The most frequent side effect is: 3

• Drowsiness (occurs in approximately 30% of patients) 3
• Dry mouth, blurred vision, constipation, urinary retention (anticholinergic effects) 1
• Orthostatic hypotension 5
• Respiratory depression (especially when combined with other CNS depressants) 5

Drug Interactions

Avoid concurrent use with: 1

• Opioid medications (risk of fatal respiratory depression)
• Alcohol or other CNS depressants
• Monoamine oxidase inhibitors (MAOIs)
• Phenothiazine antipsychotics

Key Clinical Pitfalls

• Never abruptly discontinue: Taper gradually under medical supervision to prevent life-threatening withdrawal seizures 1
• Monitor for paradoxical agitation: Occurs in approximately 10% of older adults receiving benzodiazepines 8
• Avoid long-term use: Duration beyond 4 weeks dramatically increases dependence risk 4
• Do not use as monotherapy for anxiety: The benzodiazepine component should only be used as adjunctive GI therapy, not as primary anxiolytic treatment 1