# Amitriptyline: veterinary dose and monograph

> Amitriptyline is a veterinary drug. Tricyclic antidepressant used in veterinary medicine for behaviour (anxiety, compulsive disorders), as an adjunct for NEUROPATHIC PAIN, and — a key feline use — for FELINE IDIOPATHIC CYSTITIS (interstitial cystitis) where its… Indications include feline idiopathic/interstitial cystitis (refractory cases); neuropathic pain (adjunct, multimodal); anxiety, compulsive and urine-marking behaviours. This monograph lists 3 reference doses for dogs, cats and birds, each with route, frequency and source.

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

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Tryptomer, Amitone, Elavil
- **Species with doses:** Dogs, Cats and Birds
- **General dose range:** 1–2 mg/kg PO q12–24h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Feline idiopathic/interstitial cystitis (refractory cases)
- Neuropathic pain (adjunct, multimodal)
- Anxiety, compulsive and urine-marking behaviours
- Pruritus with a behavioural/neuropathic component (adjunct)

## Amitriptyline 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

*Amitriptyline doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Neuropathic pain / anxiety (adjunct) | 1–2 mg/kg | PO | q12–24h | — |

- Neuropathic pain / anxiety (adjunct): Papich 5e: 1–2 mg/kg q12–24h PO. Plumb’s p.77: neuropathic pain 1–2 mg/kg q12–24h (Hardie; Liptak); anxiety 1–2 mg/kg q12h, up to 4 mg/kg q12h (Virga); pruritus 1–2 mg/kg q12h.

### Cats

*Amitriptyline doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Idiopathic cystitis (refractory) / anxiety | 0.5–1 mg/kg | PO | q24h | — |

- Idiopathic cystitis (refractory) / anxiety: Papich 5e: 2–4 mg per cat/day (0.5–1 mg/kg/day), can be divided q12h; idiopathic cystitis 2 mg/kg/day or 2.5–7.5 mg per cat per day (controversial). Plumb’s p.77: behaviour 0.5–1 mg/kg q12–24h or 5–10 mg per cat daily; FLUTD 2.5–12.5 mg per cat once at night, stop if no improvement in 2 months (Buffington; Bartges). Taper to stop.

### Birds

*Amitriptyline doses for birds*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Feather-damaging behaviour / anxiety | 1–5 mg/kg | PO | q12–24h | — |

- Feather-damaging behaviour / anxiety: Carpenter's 6th ed (Bird psychotropic table): 1–5 mg/kg PO q12–24h; grey parrots/cockatoos 1.5–9 mg/kg PO but plasma levels erratic and toxicity seen in ~1/3 of African greys — start low, titrate, monitor. ⚠ Severe extrapyramidal signs reported in a macaw at 5 mg/kg. Combine with environmental / behaviour modification. Plumb’s p.77 (Lightfoot 2001): 1–2 mg/kg PO q12–24h for feather plucking (anecdotal).

## Contraindications

MAO inhibitors / selegiline (serotonin syndrome). Cardiac arrhythmia/conduction disease (TCA cardiotoxicity). Glaucoma, urinary retention (anticholinergic). Seizure disorders. Hepatic impairment. Known hypersensitivity.

## Species-specific warnings

> **Caution:** Cats: Anticholinergic urinary retention is a concern in cats with lower-urinary-tract disease — monitor urination; reserve for refractory idiopathic cystitis with environmental therapy.

## Adverse effects

- Sedation (often prominent), anticholinergic effects (dry mouth, constipation, urinary retention)
- Weight gain / increased appetite
- GI upset
- Cardiac conduction effects at high dose
- Urine crystal/colour change (cats)

## Drug interactions

- MAO inhibitors / selegiline: contraindicated — serotonin syndrome
- Other serotonergic drugs: additive serotonin-syndrome risk
- Anticholinergics: additive (urinary retention, ileus)
- Antiarrhythmics / QT-prolonging drugs: additive cardiac effects
- CNS depressants: additive sedation

## Pregnancy and lactation

Limited data; avoid in pregnancy unless clearly necessary.

## Monitoring

- Clinical response (FIC signs, pain, behaviour) over weeks
- Sedation, anticholinergic effects (urination, constipation)
- Cardiac status (older patients/high doses)
- Body weight/appetite; taper when discontinuing

## Toxicity and overdose

As a TCA, overdose causes anticholinergic and CNS signs and dangerous cardiotoxicity (wide-QRS arrhythmias, hypotension, seizures) — potentially fatal. A common scenario is ingestion of human amitriptyline tablets. Cardiac effects dominate the lethal risk.

Management: Decontaminate if recent (charcoal). IV sodium bicarbonate is the cornerstone for TCA cardiotoxicity (narrows QRS, supports BP); IV fluids/vasopressors, benzodiazepines for seizures, ECG monitoring; cyproheptadine for serotonin syndrome. Intravenous lipid emulsion has been used in severe TCA toxicity. No single antidote.

## Clinical pearls

- A useful triple-duty drug: feline idiopathic cystitis (refractory), neuropathic-pain adjunct, and anxiety/compulsive behaviour
- For FIC, it is a SECOND-LINE add-on to multimodal environmental modification (MEMO), water/diet changes — not a first step
- Sedation and anticholinergic effects are common — dose at night and watch for urinary retention/constipation
- Cardiotoxic in overdose: sodium bicarbonate is the key intervention; avoid in patients with arrhythmias
- Taper rather than stop abruptly after long-term use

## Mechanism of action

Inhibits reuptake of serotonin and noradrenaline (raising CNS monoamines — anxiolytic/antidepressant and descending analgesic effects) and blocks muscarinic, histaminic, alpha-adrenergic and NMDA receptors and sodium channels. In feline idiopathic cystitis these combined actions (analgesia, anti-inflammatory, anti-anxiety, and effects on bladder sensory nerves/mast cells) underlie its benefit. The anticholinergic/antihistaminic actions cause its sedative/peripheral side effects.

## Formulations and products

- 10 mg tablet
- 25 mg tablet
- 75 mg tablet
- Tryptomer — 10 / 25 / 75 mg tablet, Tablet (human-label)
- Amitone — 10 / 25 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 Amitriptyline for dogs?

Reference doses for Amitriptyline in dogs: 1–2 mg/kg PO q12–24h (Neuropathic pain / anxiety (adjunct)). Confirm against the label and the patient before use.

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

Reference doses for Amitriptyline in cats: 0.5–1 mg/kg PO q24h (Idiopathic cystitis (refractory) / anxiety). Confirm against the label and the patient before use.

### What is the dose of Amitriptyline for birds?

Reference doses for Amitriptyline in birds: 1–5 mg/kg PO q12–24h (Feather-damaging behaviour / anxiety). Confirm against the label and the patient before use.

### When should Amitriptyline not be used?

MAO inhibitors / selegiline (serotonin syndrome). Cardiac arrhythmia/conduction disease (TCA cardiotoxicity). Glaucoma, urinary retention (anticholinergic). Seizure disorders. Hepatic impairment. Known hypersensitivity.

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

Sedation (often prominent), anticholinergic effects (dry mouth, constipation, urinary retention); Weight gain / increased appetite; GI upset; Cardiac conduction effects at high dose; Urine crystal/colour change (cats).

## Sources

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

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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.