# Terbutaline: veterinary dose and monograph

> Terbutaline is a veterinary drug. Selective β2-adrenergic agonist bronchodilator — relaxes bronchial smooth muscle for rapid relief of bronchospasm. Indications include acute bronchospasm / feline asthma crisis (SC rescue); chronic bronchitis / lower-airway disease (oral maintenance); symptomatic bradyarrhythmia (chronotropic support). This monograph lists 7 reference doses for dogs, cats, horses and ferrets, each with route, frequency and source.

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

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Brethine, Bricanyl
- **Species with doses:** Dogs, Cats, Horses and Ferrets
- **General dose range:** 0.01–0.1 mg/kg PO q8–12h (PO) / as needed (SC) — check the species tables for the indication
- **Routes:** SC, PO, IV
- **Last reviewed:** 1 October 2026

## Indications

- Acute bronchospasm / feline asthma crisis (SC rescue)
- Chronic bronchitis / lower-airway disease (oral maintenance)
- Symptomatic bradyarrhythmia (chronotropic support)

## Terbutaline 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

*Terbutaline doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Acute bronchoconstriction (parenteral) | 0.01 mg/kg | SC | as needed | — |
| Bronchodilation (oral) | 0.625–5 mg/dog | PO | q8–12h (by body size) | — |
| Premature labour (tocolysis) | 0.03 mg/kg | PO | q8h | — |

- Acute bronchoconstriction (parenteral): Plumb's (Ettinger & Kantrowitz 2005): 0.01 mg/kg IV, IM or SC. Papich 5th ed gives 3–5 mcg/kg (0.003–0.005 mg/kg) SQ as a single emergency dose, repeatable in 4–6 h — start at the lower Papich figure in a compromised patient and titrate.
- Bronchodilation (oral): Dosed by body size, not per kg. Plumb’s p.1102: small dogs 0.625–1.25 mg, medium 1.25–2.5 mg, large 2.5–5 mg per dog PO q12h (Johnson 2000; Ettinger 2005). Papich 5e: 1.25–5 mg per dog q8h PO. Bradyarrhythmias: 0.2 mg/kg PO q8–12h (Rishniw & Thomas).
- Premature labour (tocolysis): Plumb’s p.1102 (Davidson 2008): 0.03 mg/kg PO or SC q8h; stop 48 h before the calculated whelping date so normal labour can proceed.

### Cats

*Terbutaline doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Acute asthma crisis (rescue) | 0.005–0.01 mg/kg | SC | once; may repeat — a key emergency bronchodilator | — |
| Chronic bronchitis (oral) | 0.05–0.1 mg/kg | PO | q8–12h | — |

- Acute asthma crisis (rescue): Plumb’s p.1102: 0.01 mg/kg SC or IM for acute exacerbations at home — response (50% fall in respiratory rate/effort) in 15–30 min; a heart rate near 240 shows absorption (Padrid 2000); 0.01 mg/kg IV, SC or IM (Cohn 2007). Papich 5e: 5–10 µg/kg q4h SC or IM — most commonly 0.05 mg per cat (0.05 mL of 1 mg/mL) SC.
- Chronic bronchitis (oral): Papich 5e: 0.1 mg/kg q8h PO, or 0.625 mg per cat (¼ of a 2.5 mg tablet) q12h. Plumb’s p.1102 (Noone 1999): 0.312–0.625 mg per cat PO two to three times daily, up to 1.25 mg in larger cats. (0.312–0.625 mg per cat ≈ 0.06–0.125 mg/kg for a 5 kg cat.)

### Horses

*Terbutaline doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Bronchodilation (RAO / equine asthma) | 0.002–0.005 mg/kg | IV | q6–8h | — |

- Bronchodilation (RAO / equine asthma): Papich 5th ed: "Not absorbed orally. Use IV for treatment of chronic RAO: 2–5 mcg/kg q6–8h IV or as needed" (= 0.002–0.005 mg/kg). CORRECTION (2026-08-26 audit): this row previously specified 0.02–0.06 mg/kg PO — a route Papich states does not work in horses, at roughly 10× the IV dose. Inhaled beta-2 agonists (e.g. albuterol) or clenbuterol are usually preferred. Monitor for tremor/tachycardia.

### Ferrets

*Terbutaline doses for ferrets*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Bronchodilation | 2.5–5 mg/kg | PO | q12–24h | — |

- Bronchodilation: Carpenter's 6th ed (Ferret cardiopulmonary table): 2.5–5 mg/kg PO q12–24h (much higher mg/kg than dogs/cats).

## Contraindications

Tachyarrhythmia, hypertrophic cardiomyopathy with obstruction, hyperthyroidism. Caution with other sympathomimetics and in diabetic / hypertensive patients.

## Adverse effects

- Tachycardia, tremor, restlessness
- Hypokalaemia at high / repeated doses
- Excitement / nervousness

## Drug interactions

- Beta-blockers: antagonise the bronchodilator effect
- Other sympathomimetics / theophylline: additive tachycardia and hypokalaemia
- Non-potassium-sparing diuretics: additive hypokalaemia
- Inhalant anaesthetics (halothane): arrhythmia risk

## Pregnancy and lactation

Relaxes uterine smooth muscle (a tocolytic) — avoid near term; otherwise use only if necessary.

## Monitoring

- Respiratory rate / effort (efficacy)
- Heart rate / rhythm and tremor
- Serum potassium with high or repeated dosing

## Toxicity and overdose

Overdose causes marked tachycardia / tachyarrhythmia, tremor, agitation and hypokalaemia.

Management: Supportive — a cautious beta-blocker (e.g. propranolol) for severe tachyarrhythmia (weigh bronchospasm risk), correct hypokalaemia, IV fluids and ECG monitoring.

## Clinical pearls

- Keep injectable terbutaline in the feline-asthma crash kit — SC dosing buys you time in a cat in respiratory distress
- A home SC dose taught to owners can rescue a known asthmatic cat before transport
- Tremor and tachycardia are expected β2 effects; persistent tachyarrhythmia means back off the dose

## Mechanism of action

Selective β2-adrenergic agonist. Stimulates β2 receptors on bronchial smooth muscle, raising cyclic AMP to cause bronchodilation; also produces β2-mediated vasodilation, skeletal-muscle tremor and an intracellular potassium shift, with mild β1-mediated positive chronotropy.

## Formulations and products

- Terbutaline 2.5 mg tablet
- Terbutaline 5 mg tablet
- Terbutaline 1 mg/mL injection
- Bricanyl — 2.5 / 5 mg tablet; 0.5 mg/mL injection, Tablet / injection (human-label)

## Storage

Store at 15–30 °C; protect the injectable 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 Terbutaline for dogs?

Reference doses for Terbutaline in dogs: 0.01 mg/kg SC as needed (Acute bronchoconstriction (parenteral)); 0.625–5 mg/dog PO q8–12h (by body size) (Bronchodilation (oral)); 0.03 mg/kg PO q8h (Premature labour (tocolysis)). Confirm against the label and the patient before use.

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

Reference doses for Terbutaline in cats: 0.005–0.01 mg/kg SC once; may repeat — a key emergency bronchodilator (Acute asthma crisis (rescue)); 0.05–0.1 mg/kg PO q8–12h (Chronic bronchitis (oral)). Confirm against the label and the patient before use.

### What is the dose of Terbutaline for horses?

Reference doses for Terbutaline in horses: 0.002–0.005 mg/kg IV q6–8h (Bronchodilation (RAO / equine asthma)). Confirm against the label and the patient before use.

### When should Terbutaline not be used?

Tachyarrhythmia, hypertrophic cardiomyopathy with obstruction, hyperthyroidism. Caution with other sympathomimetics and in diabetic / hypertensive patients.

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

Tachycardia, tremor, restlessness; Hypokalaemia at high / repeated doses; Excitement / nervousness.

## Sources

- Plumb's Veterinary Drug Handbook
- 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.