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Theophylline for Dogs and Cats

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General Drug Information and Indications
How to Give this Medication
Side Effects
Drug Interactions
Search for Available Dosage Forms 

General Drug Information and Indications

Theophylline is a bronchodilator that is used in both dogs and cats to relax bronchial smooth muscle and open constricted airways in the lungs. It also has some anti-inflammatory effects and may improve the clearance of secretions from the lungs. Theophylline is available in both an oral and an injectable form. It is very well absorbed after oral administration.

Theophylline is most commonly used in feline asthma and in chronic bronchitis in dogs. Theophylline may be used with corticosteroids, and may permit the use of a lower dose of the corticosteroid. Like many other drugs in veterinary medicine, this drug is not FDA approved for use in animals and is not available from a veterinary pharmaceutical manufacturer. Instead, it is compounded by a specialty pharmacy. 

How to Give this Medication

Give this medication to your pet exactly as your veterinarian prescribes. If you miss giving your pet a dose of theophylline, give the next dose as soon as you remember or, if it is close to the next scheduled dose, return to the regular schedule. Do not double dose to catch up.

Due to the way this drug is metabolized, the dose for your pet will be calculated based on their ideal or lean body weight.

Theophylline levels can be measured, and your animal’s dose may be adjusted based on monitoring their blood level.

Wash your hands after giving your pet this medication. 

Side Effects

Be sure to discuss any side effects with your veterinarian immediately.

The most common side effects are central nervous system stimulation including excitement or restlessness and gastrointestinal upset. Many of the milder side effects occur at the start of therapy but will resolve over time. Some clinicians will start an animal on a lower dose and increase the theophylline to the therapeutic dose after the first week.

Less common but more serious side effects include abnormal heart rhythm and seizures.


Keep this and all drugs out of reach of children. This drug should only be given to the animal for which it was prescribed. Do not give this medication to a person. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Theophylline should be used with additional caution in animals with severe heart disease, gastrointestinal ulceration, kidney or liver disease, high blood pressure, or low blood oxygen saturation. It should be used with additional caution in animals with abnormal heart rhythm, and in those with a history of seizures.

Very young and very old animals may metabolize this drug more slowly.

Theophylline should only be used in pregnant or nursing animals when the possible benefits outweigh the risks. It both crosses the placenta, and is found in maternal milk..

Drug Interactions

Be sure to review with your veterinarian any medications or supplements your pet may be receiving.

There are a number of possible drug interactions with theophylline including: Allopurinal, beta-blockers, propanolol, cimetidine, calcium channel blockers, corticosteroids, thiabendazole, exogenous thyroid hormone, macrolide antibiotics, flouroquinolones antibiotics, barbiturates, rifampin, carbamazine, charcoal, phenytoin, ketoconazole, beta-agonists, lithium, pancuronium, propofol, isoniazid, furosemide, ephedrine, isoproterenol, halothane, and ketamine.


If you suspect your pet or another animal was overdosed accidentally or has eaten this medication inadvertently, contact your veterinarian or the A.S.P.C.A.’s Animal Poison Control Center at 888.426.4435. Always bring the prescription container with you when you take your pet for treatment.

If you or someone else has accidentally ingested this medication call the National Capital Poison Center at 800.222.1222.


Different strengths or dosage forms of theophylline may have different storage requirements. Read the labeling or ask your pharmacist for the storage requirements of the prescription you receive. 

About the Author

Dr. Barbara Forney is a veterinary practitioner in Chester County, Pennsylvania. She has a master's degree in animal science from the University of Delaware and graduated from the University of Pennsylvania School of Veterinary Medicine in 1982.

She began to develop her interest in client education and medical writing in 1997. Recent publications include portions of The Pill Book Guide to Medication for Your Dog and Cat, and most recently Understanding Equine Medications published by the Bloodhorse.

Dr. Forney is an FEI veterinarian and an active member of the AAEP, AVMA, and AMWA.

The information contained on this site is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the products shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular product. You should consult your doctor about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the products to diagnose, cure or prevent disease. 

Wedgewood Pharmacy compounded veterinary preparations are not intended for use in food and food-producing animals.