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Azapirone — Non-benzodiazepine Anxiolytic Pregnancy: Avoid — insufficient safety data in pregnancy. Use sertraline or CBT for anxiety in pregnancy.

Buspirone

Brand names: Buspar

Adult dose

Dose: GAD (generalised anxiety disorder): 5mg BD–TDS initially; increase by 5mg every 2–3 days; usual maintenance 15–30mg daily; maximum 45mg daily.
Route: Oral
Frequency: Two to three times daily
Max: 45mg daily
5-HT1A partial agonist — anxiolytic without sedation or dependence. Onset of anxiolytic effect is slow (2–4 weeks) — not suitable for acute anxiety. No cross-tolerance with benzodiazepines — does not prevent benzodiazepine withdrawal; cannot substitute for benzodiazepines in dependent patients. Advantage: no dependence potential, no sedation, no cognitive impairment.

Paediatric dose

Route: Oral
Frequency: Two to three times daily
Max: Not applicable
Not licensed under 18 years. Seek specialist child and adolescent psychiatry opinion.

Dose adjustments

Renal

Avoid in severe renal impairment (eGFR <30) — accumulation of active metabolites.

Hepatic

Avoid in severe hepatic impairment — significantly increased exposure.

Clinical pearls

  • Key advantage: no dependence, no sedation, no cognitive impairment — safe for patients who need to drive or operate machinery; suitable for long-term use in GAD when SSRIs are not tolerated
  • Slow onset (2–4 weeks): patients who previously took benzodiazepines will not feel the immediate anxiolytic effect — counsel that buspirone works differently and requires time; do not equate absence of immediate effect with failure
  • No cross-tolerance: switching from benzodiazepine to buspirone — taper benzodiazepine slowly and independently while building up buspirone; buspirone will not prevent BDZ withdrawal symptoms
  • Grapefruit: increases buspirone levels 4–9 fold — advise patients to avoid grapefruit juice

Contraindications

  • Epilepsy (lowers seizure threshold at high doses)
  • MAOIs within 14 days
  • Hypersensitivity to buspirone
  • Severe renal or hepatic impairment

Side effects

  • Dizziness, nausea (common at initiation)
  • Headache
  • Nervousness, excitability (paradoxical — early)
  • Sleep disturbance
  • Tachycardia
  • No sedation (distinguishes from benzodiazepines)
  • No dependence or withdrawal

Interactions

  • MAOIs — avoid (serotonin syndrome risk)
  • CYP3A4 inhibitors (erythromycin, itraconazole, diltiazem, verapamil, grapefruit) — increase buspirone levels significantly; reduce dose
  • CYP3A4 inducers (rifampicin, carbamazepine) — reduce buspirone efficacy
  • SSRIs — serotonin syndrome risk (weak)

Monitoring

  • Anxiety symptom rating at 4 weeks (delayed onset — allow full trial)
  • Blood pressure (mild BP elevation possible)
  • Liver and renal function (if prolonged use)

Reference: BNFc; BNF 90; NICE CG22 (Anxiety); NICE NG106 (GAD). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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