Diazepam (Valium): Uses, Dosage, Side Effects, and What to Expect

Diazepam (brand name: Valium) is a benzodiazepine (long-acting). Diazepam enhances GABA-A receptor activity with broad effects across the CNS — anxiolytic, anticonvulsant, muscle relaxant, and sedative. Its defining pharmacokinetic feature is its very long half-life: diazepam itself has a half-life of 20-100 hours, and its active metabolite desmethyldiazepam (nordiazepam) has a half-life of 36-200 hours. This means diazepam accumulates over days of repeated dosing and self-tapers very gradually when stopped, which is why it is the preferred benzodiazepine for cross-tapering from shorter-acting benzodiazepines.

• Anxiety disorders
• Acute alcohol withdrawal
• Muscle spasm
• Seizure disorders (adjunctive)
• Preoperative sedation

Common off-label uses:

• Benzodiazepine tapering (cross-taper from short-acting benzos)
• Spasticity (cerebral palsy, spinal cord injury)
• Panic disorder
• Restless legs syndrome
• Night terrors

Anxiety: 2-10 mg 2-4 times daily. Alcohol withdrawal: 10-20 mg initially, then titrate based on symptoms (CIWA protocol). Muscle spasm: 2-10 mg 3-4 times daily. Seizures: 5-10 mg IV/rectal. Elderly: start at 2 mg. Available as tablets, oral solution, rectal gel (Diastat), and IV/IM injection.

Oral: 15-45 minutes (fast absorption). IV: 1-3 minutes. IM: erratic absorption (not preferred). Duration: long due to half-life and active metabolites.

• Drowsiness
• Fatigue
• Muscle weakness
• Ataxia
• Memory impairment
• Confusion (especially in elderly)

• Physical dependence
• Severe withdrawal (seizures, delirium)
• Respiratory depression with opioids (black box warning)
• Accumulation in elderly (long half-life + slower metabolism = prolonged sedation)
• Paradoxical reactions
• Falls and cognitive decline in older adults

Dangerous with opioids, alcohol, and CNS depressants. CYP3A4 and CYP2C19 substrate — ketoconazole, omeprazole, and fluvoxamine increase levels. Rifampin and carbamazepine decrease levels. Unlike lorazepam, diazepam relies on hepatic oxidation, making it more susceptible to drug interactions and liver disease effects.

Category D. Associated with increased risk of cleft lip/palate. Neonatal withdrawal with late-pregnancy use. Long half-life means prolonged neonatal effects.

Paradoxically, diazepam's long half-life makes it the preferred benzodiazepine for tapering. The Ashton Manual protocol uses diazepam as a cross-taper target from shorter-acting benzos, then gradually reduces diazepam over weeks to months. Self-tapering effect reduces interdose withdrawal.