Triazolam Is the Benzodiazepine with the Shortest Half-Life
Triazolam (Halcion) is the benzodiazepine with the shortest half-life, ranging from 1.5 to 5.5 hours, making it the shortest-acting benzodiazepine available.
Pharmacokinetic Comparison of Benzodiazepines
Benzodiazepines can be classified based on their half-lives:
Ultra-short half-life
- Triazolam: 1.5-5.5 hours 1
- Onset of action: 1-2 minutes (IV), peak effect: 3-4 minutes
- Elimination is rapid with no significant accumulation
Short half-life
Medium half-life
Long half-life
- Diazepam: Longer-acting with active metabolite desmethyl-diazepam that has prolonged half-life 2
Clinical Implications of Short Half-Life Benzodiazepines
The ultra-short half-life of triazolam has several clinical implications:
- Rapid clearance: Triazolam is rapidly eliminated with minimal morning residual effects 4
- Limited duration: Effects typically don't persist into the next day at therapeutic doses (0.25-0.5 mg) 5
- Elderly considerations: In elderly patients (62-83 years), the half-life is extended, requiring lower dosing (0.125-0.25 mg) 1
Comparative Data
When comparing the three "Z" non-benzodiazepine hypnotics to benzodiazepines:
- Zaleplon: Ultra-short half-life of approximately 1 hour
- Zolpidem: Half-life of approximately 2.4 hours
- Zopiclone: Half-life of approximately 5 hours 6
Triazolam remains the benzodiazepine with the shortest half-life at 1.5-5.5 hours, comparable to these newer agents.
Important Considerations and Cautions
Withdrawal Risk
Despite its short half-life, triazolam can still cause dependence and withdrawal symptoms:
- Short-acting benzodiazepines may actually produce more severe withdrawal phenomena compared to longer-acting agents 7
- Rebound insomnia for 1-2 nights is commonly observed after discontinuation 4
Special Populations
- Elderly patients: Experience greater sedation and psychomotor impairment due to higher plasma concentrations; require reduced dosing (0.125-0.25 mg) 1
- Patients with liver disease: May have significantly prolonged half-life
Clinical Use Considerations
- Regular use can lead to tolerance, addiction, depression, and cognitive impairment 2
- Paradoxical agitation occurs in approximately 10% of patients treated with benzodiazepines 2
- When tapering benzodiazepines, a gradual approach is recommended with reductions of 0.25 mg every 1-2 weeks 8
Triazolam's ultra-short half-life makes it particularly suitable for treating insomnia without causing daytime residual effects, but this same property may increase the risk of withdrawal symptoms and rebound insomnia when discontinued.