Azapirone — Non-benzodiazepine Anxiolytic Pregnancy: SPC §4.6: there are no or limited data from use in pregnant women; animal studies do not indicate direct or indirect reproductive toxicity. As a precautionary measure it is preferable to avoid buspirone during pregnancy. The effect on labour and delivery is unknown. It is unknown whether buspirone or its metabolites are excreted in human milk — decide whether to discontinue breast-feeding or buspirone, weighing the benefit of breast-feeding to the child against the benefit of therapy to the woman.

Buspirone

Brand names: Buspar

Buspirone is a non-benzodiazepine anxiolytic used in the management of generalised anxiety disorder, often where avoidance of benzodiazepine-related sedation and dependence is desirable.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 5 mg two to three times daily initially, increased every 2–3 days; usual therapeutic dose 15–30 mg daily in divided doses

Route: Oral (source product: buspirone hydrochloride 10 mg tablets)

Frequency: Two to three times daily (divided doses)

Max: 45 mg daily in divided doses

SPC §4.2: 'Adults (including the elderly): the usual starting dosage is 5mg given two to three times per day. The dosage may be increased every 2-3 days. The usual therapeutic dosage is 15 to 30mg daily in divided doses. The maximum recommended dose is 45mg daily in divided doses.' The dose should be individualised for each patient. Food increases buspirone bioavailability — take at the same time each day and consistently either with or without food. Avoid large quantities of grapefruit juice (it increases buspirone plasma concentrations). If given with a potent CYP3A4 inhibitor, lower the initial dose and increase only gradually after medical evaluation. HEPATIC IMPAIRMENT: reduced first-pass effect; in cirrhosis, higher peak concentrations and a longer half-life — use with caution, titrate individual doses carefully to reduce central adverse effects, and consider dose increases only after 4–5 days' experience with the prior dose. Severe hepatic impairment is contraindicated. CHILDREN: placebo-controlled trials in 334 patients treated for up to six weeks did not show buspirone at adult doses to be an effective treatment for generalised anxiety disorder in patients under 18; plasma concentrations of buspirone and its active metabolite were higher in paediatric patients than in adults at equivalent doses. Long-term safety and effectiveness under 18 have not been determined and buspirone is not recommended in children and adolescents — no paediatric dose is given, so no structured paedDose is recorded. WITHDRAWAL OF PRIOR SEDATIVES: buspirone does not show cross-tolerance with benzodiazepines or other sedative/hypnotics and will not block their withdrawal syndrome — withdraw those agents gradually before starting buspirone. Buspirone should not be used alone to treat depression and may mask its clinical signs.

Dose adjustments

Renal

SPC §4.2: in mild to moderate renal insufficiency (creatinine clearance 20–49 ml/min/1.72 m²) blood levels rise slightly without a change in half-life — administer with caution at a low dosage twice daily, and evaluate response and symptoms carefully before any dose increase. Buspirone should NOT be given to patients with creatinine clearance <20 ml/min/1.72 m², especially anuric patients, because increased and untreated levels of buspirone and its metabolites may occur; dialysis did not influence buspirone or 1-PP levels.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION The recommended initial dose is 15 mg daily (7.5 mg b.i.d.). To achieve an optimal therapeutic response, at intervals of 2 to 3 days the dosage may be increased 5 mg per day, as needed. The maximum daily dosage should not exceed 60 mg per day. In clinical trials allowing dose titration, divided doses of 20 to 30 mg per day were commonly employed. The bioavailability of buspirone is increased when given with food as compared to the fasted state (see CLINICAL PHARMACOLOGY ). Consequently, patients should take buspirone in a consistent manner with regard to the timing of dosing; either always with or always without food. When buspirone is to be given with a potent …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2019-05-03. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Known hypersensitivity to buspirone hydrochloride or any ingredient in the tablet
Epilepsy
Acute intoxication with alcohol, hypnotics, analgesics or antipsychotic drugs
Severe renal impairment (creatinine clearance 20 ml/min or below, or plasma creatinine above 200 µmol/l)
Severe hepatic impairment
US label additionally: MAOIs intended to treat depression, concurrently or within 14 days either side; starting buspirone in a patient on a reversible MAOI such as linezolid or intravenous methylene blue (serotonin syndrome risk)

Side effects

Very common: dizziness (including lightheadedness), headache, somnolence
Common: nervousness, insomnia, disturbance in attention, depression, confusional state, sleep disorder, anger
Common: paraesthesia, blurred vision, abnormal coordination, tremor, tinnitus; tachycardia, chest pain; fatigue
Common: nausea, abdominal pain, dry mouth, diarrhoea, constipation, vomiting; nasal congestion, pharyngolaryngeal pain; cold sweat, rash; musculoskeletal pain
Very rare: serotonin syndrome, convulsion, extrapyramidal disorder, dystonia, dyskinesia, akathisia, Parkinsonism, syncope, amnesia, ataxia; psychotic disorder, hallucination, depersonalisation; urinary retention; galactorrhoea. Rare: angioneurotic oedema, urticaria, ecchymosis

Interactions

MAO inhibitors — co-administration may cause increases in blood pressure and is not recommended (UK SPC); US label treats this as a contraindication and requires at least 14 days between stopping an MAOI antidepressant and starting buspirone, and vice versa
Reversible MAOIs (linezolid, intravenous methylene blue) — increased risk of serotonin syndrome; if urgently needed, stop buspirone promptly and monitor for serotonin syndrome for 2 weeks or until 24 hours after the last dose, whichever comes first (US label)
Potent CYP3A4 inhibitors (SPC names erythromycin; further list truncated at the fetch limit) — lower the initial buspirone dose and increase only gradually after medical evaluation
Grapefruit juice — increases buspirone plasma concentrations; patients should avoid large quantities
Other CNS-active drugs — concomitant use should be approached with caution
Benzodiazepines and other sedative/hypnotics — no cross-tolerance; buspirone will not block their withdrawal syndrome, so withdraw them gradually before starting buspirone

Clinical monograph

How it works

It is a partial agonist at presynaptic and postsynaptic 5-HT1A serotonin receptors, modulating serotonergic neurotransmission. Unlike benzodiazepines it has no direct action at the GABA receptor and lacks sedative, anticonvulsant and muscle-relaxant properties.

Prescribing in practice

Its anxiolytic effect develops gradually over one to two weeks, so it is unsuitable for acute anxiety or 'as-needed' relief and should be taken regularly; it does not produce the dependence associated with benzodiazepines.
Common effects include dizziness, nausea, headache and light-headedness.
It is metabolised by CYP3A4, so concentrations are raised by CYP3A4 inhibitors (avoid grapefruit juice) and there is a risk of serotonin syndrome if combined with MAOIs — see the SPC for interaction detail.

Monitoring

Review anxiety symptoms and tolerability after the first couple of weeks, since onset is delayed. Be alert for features of serotonin syndrome when other serotonergic drugs are co-prescribed, and reassess interacting medicines and dose where CYP3A4 inhibitors or inducers are involved.

Counselling the patient

Take this medicine regularly every day — it is not a 'when needed' treatment and can take one to two weeks before you notice the benefit.
Avoid grapefruit and grapefruit juice, which can raise the amount of medicine in your body.
Tell your prescriber about all other medicines you take, and report agitation, sweating, shivering or a racing heartbeat.

Evidence & guidelines

A recognised non-benzodiazepine option for generalised anxiety disorder in UK practice (NICE), valued for its lack of dependence compared with benzodiazepines.

Reference: NICE CG22 (Anxiety); NICE NG106 (GAD); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways