Buspirone
Buspirone HCl
Also known as: BuSpar · MJ-9022
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Low-grade anxieties and fears | 1 mg/kg PO q8-24h (mild anxiety); 2.5-10 mg (total dose) per dog PO q8-24h (mild anxiety); 10-15 mg per dog PO q8-12h (more severe anxiety, thunderstorm phobia) | PO | q8-24h or q8-12h | — | 🌎 NA |
| Low-grade anxieties and fears | 1-2 mg/kg PO q12h; 5-15 mg (total dose) per dog PO q8-12h | PO | q8-12h or q12h | — | 🌎 NA |
| Low-grade anxieties and fears | 5-10 mg (total dose) PO q8-12h | PO | q8-12h | — | 🌎 NA |
| Global anxiety | 0.5-2 mg/kg PO q8-12h | PO | q8-12h | may take 2-4 weeks until effect | 🌎 NA |
| Social phobias, panic disorders | 1 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
- Social phobias, panic disorders: most useful in social phobias; may also be useful for panic disorders
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Adjunctive treatment of low-grade anxieties/fears, spraying, overgrooming | 0.5-1 mg/kg PO q8-12h; 2.5-5 mg (total dose) per cat PO q8-12h | PO | q8-12h | 6-8 weeks | 🌎 NA |
| Adjunctive treatment of low-grade anxieties/fears, spraying, overgrooming | 2.5-5 mg (total dose) PO once a day to 3 times a day | PO | q8-24h | — | 🌎 NA |
| Urine marking | 2.5-7.5 mg (total dose) per cat PO q12h | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of low-grade anxieties/fears, spraying, overgrooming | 0.5-1 mg/kg PO q12h; 2.5-7.5 mg (total dose) per cat PO q12h | PO | q12h | — | 🌎 NA |
| Social phobias, panic disorders | 0.5-1 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
- Adjunctive treatment of low-grade anxieties/fears, spraying, overgrooming: some cats do well on once daily dosing
- Social phobias, panic disorders: most useful in social phobias; may also be useful for panic disorders
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Buspirone is an azapirone-class, non-benzodiazepine anxiolytic agent used primarily in veterinary medicine for the management of generalized anxiety, mild phobias, and feline urine marking/spraying.
Unlike benzodiazepines, buspirone lacks sedative, muscle relaxant, and anticonvulsant properties, making it ideal for long-term behavioral management without causing significant cognitive or psychomotor impairment.
Clinical Pearls:
- Delayed Onset: It requires chronic administration (typically 1 to 4 weeks) to alter receptor density and achieve full clinical efficacy.
- Not for Acute Panic: Because of its delayed onset, it is inappropriate and ineffective as a sole therapy for acute, situational panic (e.g., immediate thunderstorm response or acute separation anxiety events).
- Social Dynamics: It is particularly useful for anxieties associated with social interactions and may be more effective in multi-cat households than in single-cat households.
Mechanism of action
Buspirone is an anxioselective agent that acts primarily as a partial agonist at serotonin (5-HT1A) receptors and as an agonist/antagonist at presynaptic dopamine (D2) receptors in the CNS.
- Serotonin Pathway: By binding to 5-HT1A autoreceptors → it slows the neuronal firing rate → decreasing the depletion of serotonin stores and modulating serotonergic tone over time.
- Receptor Specificity: It does not share mechanisms with benzodiazepines; it has no significant affinity for benzodiazepine receptors and does not affect GABA binding.
Safety & warnings
Contraindications
- Severe hepatic disease (use with caution)
- Severe renal disease (use with caution)
- Aggressive animals (may reduce disinhibition)
- Working dogs (use with caution despite low sedation)
- Acute situational anxieties (as sole therapy)
Adverse effects
- Bradycardia
- Gastrointestinal disturbances
- Stereotypic behaviors
- Increased affection (cats)
- Paradoxical aggression/turning on attackers (previously timid cats)
- Dizziness (humans)
- Headache (humans)
- Nausea/anorexia (humans)
- Restlessness (humans)
- Tachycardia (rare)
Precautions
Buspirone should be used with caution in patients with significant renal or hepatic disease. Because buspirone may reduce disinhibition, it should be used with caution in aggressive animals. While it has far less sedating properties than many other anxiolytic drugs, it should be used with caution in working dogs. It often takes a week or more for effect, so it should not be used as the sole therapy for situational anxieties. Avoid use during nursing if possible, as it is distributed into maternal milk.
Drug interactions
May be used in combination, but dosage reductions may be necessary to minimize adverse effects
Potentially could cause increased CNS depression
May cause increased buspirone plasma levels and adverse effects
May cause increased buspirone plasma levels and adverse effects
May cause increased buspirone plasma levels and adverse effects
May cause increased buspirone plasma levels and adverse effects
Use with buspirone is not recommended because dangerous hypertension may occur
May cause decreased buspirone plasma levels
Use with buspirone may cause increased ALT
May cause increased buspirone plasma levels
Monitoring
- Efficacy (reduction in anxiety, spraying, or fear behaviors)
- Adverse effect profiles (GI upset, behavioral changes)
Pharmacokinetics
Absorption
In humans, rapidly and completely absorbed but high first-pass effect limits systemic bioavailability to ~5%. In cats, oral peak levels occur in about 1.4 hours, but oral bioavailability appears significantly lower than in humans. Transdermal administration (PLO-base) does not yield detectable levels.
Distribution
Binding to plasma proteins is very high (95%). Highest tissue concentrations in lungs, kidneys, and fat. Distributed into maternal milk.
Metabolism
Hepatically metabolized to several metabolites, including one active metabolite (1-PP).
Elimination
Metabolites are excreted primarily in the urine.
Overdose
Limited information is available in veterinary species. The oral LD50 in dogs is 586 mg/kg.
Clinical Signs of Overdose:
- Vomiting
- Dizziness
- Drowsiness
- Miosis (constricted pupils)
- Gastric distention
Treatment: Standard overdose protocols (e.g., decontamination, supportive care) should be followed after ingestion has been determined.
Available products
Formulations
- Oral Tablets
Human-labeled
- Buspirone HCl Oral Tablets: 5 mg, 7.5 mg, 10 mg, 15 mg, and 30 mg (BuSpar, generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Tablets should be stored in tight, light-resistant containers at room temperature. After manufacture, buspirone tablets have an expiration date of 36 months.
Client information
Important: This medication is not a "quick fix" and requires consistency.
- Patience is Key: It typically takes 1 to 4 weeks of daily use to see noticeable improvements in your pet's behavior.
- Do Not Use As-Needed: It must be given consistently every day. Giving it only during a stressful event (like a thunderstorm) will not work.
- Behavioral Changes in Cats: If used in a multi-cat household, a previously timid cat may become more confident and potentially stand up to or attack a bully cat. Monitor their interactions closely.
- Side Effects: Generally very safe. You might notice mild stomach upset, dizziness, or changes in affection levels (cats may become unusually cuddly).
- Missed Doses: If you miss a dose, give it when you remember, but never double up on doses.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.