# Sertraline: veterinary dose and monograph

> Sertraline is a veterinary drug. A selective serotonin reuptake inhibitor (SSRI) — used, like fluoxetine, for canine and feline BEHAVIOUR problems: generalised anxiety, fear-based aggression, compulsive disorders, and (in cats) anxiety/urine marking. Indications include 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. This monograph lists 2 reference doses for dogs and cats, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/sertraline · Last reviewed: 2026-10-01

## 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

*Sertraline doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Anxiety / aggression / compulsive disorder | 1–3 mg/kg | PO | q24h | — |

- 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

*Sertraline doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Anxiety / urine marking / compulsive | 0.5–1.5 mg/kg | PO | q24h | — |

- 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

> **Caution:** 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

> **Caution:** 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.

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## Frequently asked questions

### What is the dose of Sertraline for dogs?

Reference doses for Sertraline in dogs: 1–3 mg/kg PO q24h (Anxiety / aggression / compulsive disorder). Confirm against the label and the patient before use.

### What is the dose of Sertraline for cats?

Reference doses for Sertraline in cats: 0.5–1.5 mg/kg PO q24h (Anxiety / urine marking / compulsive). Confirm against the label and the patient before use.

### When should Sertraline not be used?

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.

### What are the side effects of Sertraline in animals?

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.

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.