Theophylline

1,3-dimethyl-7H-purine-2,6-dione

Bronchodilator - MethylxanthinePODogsCats

Also known as: Corvental-D · Theophyllinum · Anhydrous theophylline

Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference

20 mg/kg or 10-15 mg/kgPO· q24h or q12h· Continuous

Body weight— 🐕

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
Bronchodilation	20 mg/kg or 10-15 mg/kg	PO	q24h or q12h	Continuous	🌍 EU

Bronchodilation: 20 mg/kg p.o. q24h or 10 mg/kg p.o. q12h which may be increased to 15 mg/kg p.o. q12h if no side effects on lower dose. Manufacturer only recommends q24h dosing. Some texts indicate q12h dosing of the sustained-release preparation is required to maintain therapeutic serum levels.

Cats

Indication	Dose	Route	Frequency	Duration	Region
Bronchodilation	15-19 mg/kg	PO	q24h	Continuous	🌍 EU

Bronchodilation: Sustained-release preparation.

Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.

Recording this consult? VetSheet's AI writes the drug, dose and duration straight into a structured visit note.See how VetSheet works

Overview

Theophylline is a methylxanthine bronchodilator used primarily in the management of small airway disease in dogs and cats. Beneficial effects include bronchodilation, enhanced mucociliary clearance, stimulation of the respiratory centre, increased sensitivity to PaCO2, increased diaphragmatic contractility, stabilization of mast cells, and a mild inotropic effect. It also acts as a spasmolytic agent with mild diuretic action.

Clinical Warning: Theophylline has a low therapeutic index (therapeutic plasma values are 5-20 µg/ml). It must be dosed based on lean body weight to avoid toxicity.

Mechanism of action

Causes inhibition of phosphodiesterase enzymes and antagonism of adenosine and prostaglandin receptors → increased intracellular cAMP → smooth muscle relaxation and bronchodilation. It also alters intracellular calcium and stimulates catecholamine release, providing mild inotropic and diuretic effects.

Safety & warnings

Contraindications

Patients with a known history of arrhythmias
Patients with a known history of seizures

Adverse effects

Vomiting
Diarrhoea
Polydipsia
Polyuria
Reduced appetite
Tachycardia
Arrhythmias
Nausea
Twitching
Restlessness
Agitation
Excitement
Convulsions
Hyperaesthesia (cats)

Precautions

Administer with caution in patients with:

Severe cardiac disease
Gastric ulcers
Hyperthyroidism
Renal or hepatic disease
Severe hypoxia
Severe hypertension

Note: Most adverse effects are related to the serum level and may be symptomatic of toxic serum concentrations. The severity of these effects may be decreased by the use of modified-release preparations. They are more likely to be seen with more frequent administration.