Theophylline

Theophylline In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Causes inhibition of phosphodiesterase, alteration of intracellular calcium, release of catecholamine, and antagonism of adenosine and prostaglandin.
• Results in bronchodilation and other effects.
• Functions as a spasmolytic agent and has a mild diuretic action.

Uses of Theophylline

• Employed in the treatment of small airway disease.
• Beneficial effects encompass bronchodilation, enhanced mucociliary clearance, stimulation of the respiratory center, increased sensitivity to PaCO2, heightened diaphragmatic contractility, stabilization of mast cells, and a mild inotropic effect.

Dose of Theophylline in Dogs and Cats

Dogs:

• 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 (NB: manufacturer only recommends q24h dosing).
• Some texts indicate q12h dosing of the sustained-release preparation is required to maintain therapeutic serum levels.

Cats:

• Bronchodilation: 15–19 mg/kg p.o. q24h (sustained-release preparation).

Side Effects of Theophylline in Dogs and Cats

• Adverse effects may include vomiting, diarrhoea, polydipsia, polyuria, reduced appetite, tachycardia, arrhythmias, nausea, twitching, restlessness, agitation, excitement, and convulsions.
• Cats may exhibit hyperaesthesia.
• Most adverse effects correlate with serum levels and may indicate toxic concentrations.
• The severity of these effects can be mitigated with modified-release preparations, but they are more likely with frequent administration.

Contraindications of Theophylline in Dogs and Cats

• Patients with a known history of arrhythmias or seizures.

Some Notes: