Buspirone (Buspar®) vs Clonazepam (Klonopin®)
Based on "Essential Psychopharmacology"
written by Stephen M. Stahl, MD, PhD
Key differences between Buspirone and Clonazepam
- Buspirone is an anxiolytic with a unique structure and pharmacology.
- Buspirone alleviates anxiety without causing sedation or functional impairment.
- Buspirone is NOT a controlled substance and does not promote abuse or physical dependence.
- In contrast to clonazepam, buspirone lacks anticonvulsant and muscle relaxant properties.
- The onset of anxiolytic effect is much more pronounced and rapid with clonazepam. Buspirone is ineffective when taken irregularly.
- Buspirone is ineffective for occasional use and is useless for acute situational anxiety or insomnia.
- It may take 1-2 weeks for beneficial antianxiety effects become noticeable.
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| Buspirone | Clonazepam |
| • Buspar® |
• Klonopin® |
| Drug class | |
| • Azapirone (azaspirodecanedione) derivative, structurally unrelated to benzodiazepines | • Benzodiazepine, long acting |
| Legal status | |
| • Rx only | • Rx only • Schedule IV Controlled substance |
| Dose formulations | |
| • Oral tablets | • Oral tablets • Oral disintegrating wafers |
| FDA-approved indications | |
| • Generalized Anxiety Disorder (GAD) • Short-term relief of anxiety symptoms |
• Panic disorder • Lennox-Gastaut syndrome • Akinetic seizure • Myoclonic seizure • Acute mania • Acute psychosis |
| "Off-label" uses | |
| • Depression4, mainly as augmenting agent to antidepressants • Smoking cessation3 • Behavioural disturbances (agitation, aggression) |
• Insomnia5 • Anxiety disorders |
| Therapeutic actions | |
| • Delayed anxiolytic effect, useful mainly for GAD • Buspirone lacks an immediate anti-anxiety effects. |
• Rapid anxiolytic effect, works for a wide range of anxiety disorders • Anticonvulsant • Muscle-relaxant • Hypnotic (sleep inducing) |
| Half-life | |
| • 2-3 hours | • 30-40 hours |
| Oral bioavailability | |
| • 5% | • 90% |
| Contraindications | |
| • History of sensitivity to buspirone | • History of sensitivity to benzodiazepines • Acute narrow angle glaucoma • Significant liver disease |
| Side effects | |
| • Dizziness • Nausea • Drowsiness • Headache • Buspirone does NOT impair cognitive performance, memory, or driving skills • NO withdrawal symptoms after buspirone discontinuation |
• Sedation • Performance impairment • Memory impairment • Dizziness • Fatigue • Physical dependence • Potentiates effects of alcohol and CNS • Withdrawal symptoms after clonazepam discontinuation |
| Pregnancy category | |
| • B | • D |
| Onset of therapeutic effect | |
| • After 4-6 weeks |
• Rapid onset of antianxiety action, within 1-5 min. |
Further reading
References
- 1. Prescribing Information for Buspar® (Buspirone)
- 2. Prescribing Information for Klonopin® (Clonazepam)
- 3. Farid P, Abate MA. Buspirone use for smoking cessation. Ann Pharmacother. 1998 Dec;32(12):1362-4.
- 4. Rickels K, Amsterdam JD, Clary C, Puzzuoli G, Schweizer E. Buspirone in major depression: a controlled study. J Clin Psychiatry. 1991 Jan;52(1):34-8. PubMed
- 5. Minkel J, Krystal AD. Optimizing the Pharmacologic Treatment of Insomnia: Current Status and Future Horizons. Sleep Med Clin. 2013 Sep 1;8(3):333-350. PubMed
Published: December 20, 2018
Last reviewed: December 20, 2018
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Interesting facts
- Buspirone may have a major advantage over benzodiazepines for patients who cannot afford impairment in psychomotor skills.
