Sertraline: veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Zoloft, Serta, Daxid

Species with doses

Dogs and Cats

General dose range

1–3 mg/kg PO q24h — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Canine generalised anxiety, fear/anxiety-based aggression, compulsive disorders
• Feline anxiety, fear, and urine marking/spraying
• Situational/chronic anxiety as part of a behaviour-modification programme
• Alternative SSRI when fluoxetine is ineffective/not tolerated

Sertraline dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Anxiety / aggression / compulsive disorder: Plumb’s p.1056: 1–3 mg/kg PO once daily for 3–6 months with behaviour modification, then wean by halving weekly over 2–4 weeks (Neilson); 1–2 mg/kg q24h (Virga); compulsive disorder 2–4 mg/kg once daily or divided q12h (Landsberg); generalised anxiety 0.5–4 mg/kg once daily (Crowell-Davis; Haug). Allow 4–8 weeks for a trial. Not in Papich 5e. Never combine with MAOIs (selegiline, amitraz) or tramadol.

Cats

• Anxiety / urine marking / compulsive: Plumb’s p.1056: 0.5–1 mg/kg PO once daily for urine marking, aggression, anxiety or phobias (Virga; Crowell-Davis; Seibert); generalised anxiety 0.5–1.5 mg/kg q24h; compulsive disorder 0.5 mg/kg (Landsberg); 0.25–1.3 mg/kg (Curtis). Treat at least 4–6 months and wean over 3–5 weeks. Monitor appetite.

Contraindications

Concurrent MAO inhibitors / selegiline and (caution) other serotonergic drugs (serotonin syndrome — observe washouts). History of seizures (lowers threshold). Known hypersensitivity. Hepatic impairment (hepatically metabolised). Not a quick fix — requires behaviour modification.

Species-specific warnings

Cats: Monitor appetite closely (anorexia risk) and use low mg/kg; expect a slow onset — pair with environmental/behaviour modification.

Adverse effects

• Reduced appetite / GI upset, especially early (transient)
• Lethargy or, conversely, restlessness/agitation early
• Lowered seizure threshold (rare)
• Serotonin syndrome if combined with other serotonergic drugs

Drug interactions

• MAO inhibitors / selegiline (Anipryl): contraindicated — serotonin syndrome (observe washouts both ways)
• Other serotonergic drugs (tramadol, TCAs, trazodone, ondansetron, mirtazapine): additive serotonin-syndrome risk
• CYP inhibition: can raise levels of some co-metabolised drugs
• Drugs lowering seizure threshold: additive risk

Pregnancy and lactation

Limited veterinary data; generally avoided in pregnancy unless clearly necessary.

Monitoring

• Behavioural response over 4–6 weeks (set owner expectations)
• Appetite/weight (early anorexia) and demeanour
• Concurrent serotonergic medications (avoid)
• Taper when discontinuing long-term therapy

Toxicity and overdose

Overdose causes serotonergic signs — agitation, tremor, hyperthermia, tachycardia, mydriasis, vomiting and, at high doses, seizures and serotonin syndrome. A common scenario is a pet ingesting the owner's human sertraline. Effects can be prolonged.

Management: Decontaminate if recent ingestion (emesis/charcoal). For serotonin syndrome: cyproheptadine (serotonin antagonist), active cooling, IV fluids, control agitation/seizures with benzodiazepines, and supportive monitoring (temperature, ECG). No specific antidote.

Clinical pearls

• An SSRI alternative to fluoxetine for canine/feline anxiety, aggression and compulsive disorders — same principles: give it 4–6 weeks and combine with behaviour modification
• Never combine with MAO inhibitors/selegiline or stack with other serotonergic drugs (tramadol, trazodone, mirtazapine) — serotonin-syndrome risk
• A frequent human-drug ingestion in pets — manage overdose as serotonin toxicity (cyproheptadine, cooling, benzodiazepines)
• Watch early appetite loss (especially cats); taper rather than stop abruptly

Mechanism of action

Selectively inhibits the presynaptic serotonin (5-HT) transporter, increasing synaptic serotonin in the CNS; over weeks this produces adaptive receptor changes that reduce anxiety, impulsivity/aggression and compulsive behaviour — the delayed onset reflecting these neuroadaptations rather than the immediate reuptake block. It has less effect on other neurotransmitter systems than tricyclic antidepressants (fewer anticholinergic/cardiac effects).

Formulations and products

• 25 / 50 mg tablet
• 100 mg tablet
• Zoloft / Daxid — 25 / 50 / 100 mg tablet, Tablet (human-label)

Storage

Tablets: 15–30 °C, dry, protect from light.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other hormones, emergency drugs, supplements and other drugs

• Protamine Sulfate
• Pyridostigmine
• Salbutamol (Albuterol)
• Selegiline (L-Deprenyl)
• Sodium Bicarbonate
• Succimer (DMSA)
• Terbutaline
• Theophylline

Frequently asked questions