Theophylline for Dogs: A Medication to Stop the Cough

Just like people, all dogs cough every now and then. Sometimes, though, a cough can become your dog’s constant companion. 

Chronic coughing can have different causes, each of which requires a different treatment. In some cases, however, your veterinarian may recommend treatment with theophylline.

Find out how theophylline is used in dogs and how it works. 

Theophylline for dogs at a glance

What is theophylline for dogs and how does it work?

Theophylline is a bronchodilator medication. Its main effect is to open up your dog’s airways by relaxing smooth muscle in their respiratory system. 

Theophylline can also: 

• Reduce inflammation in the trachea and lungs 

• Help cilia (hairs) in the respiratory tract beat faster to remove debris from the lungs

• Stimulate heart activity 

• Stimulate the central nervous system 

• Help eliminate excess fluid from a dog’s body

What is theophylline used for in dogs?

Veterinarians use theophylline to treat chronic coughing associated with airway constriction. While many conditions can cause a cough in dogs, the most common uses for theophylline in dogs include:

• Tracheal collapse

• Bronchitis

• Asthma

• Congestive heart failure

Theophylline is a human medication that is used off-label in dogs. Although theophylline is not FDA approved for use in dogs, it is considered safe and effective. 

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How is theophylline given to dogs?

Your veterinarian will determine the best theophylline dose for your dog. Your dog's starting dose will be based on their weight and the condition being treated. Every dog responds to this medication differently, so your veterinarian may need to adjust your dog’s dose once you start treatment. 

While injectable theophylline is available for use in emergencies, theophylline is usually given by mouth. It is available as a tablet, capsule, or liquid. You can give it with food or on an empty stomach.

Oral theophylline is available in two forms: immediate release and sustained release. Immediate-release theophylline is typically given every 6 to 8 hours. Sustained-release theophylline is usually given once or twice daily. Your veterinarian will determine the best dosing schedule for your dog. 

What are the common side effects of theophylline in dogs?

The most common side effects associated with theophylline are gastrointestinal (GI) effects. These may include: 

• Loss of appetite

• Nausea

• Vomiting

• Diarrhea

You can reduce the risk of GI effects by giving your dog’s theophylline with a meal. If GI side effects continue, contact your veterinarian. They may recommend a change in dosage or switching to a different medication.

Other side effects that may be associated with theophylline include:

• Restlessness

• Excitability

• Increased water intake

• Increased urination

To reduce the risk of side effects, veterinarians typically avoid using theophylline in dogs with a history of: 

• Kidney disease

• Liver disease

• Diabetes

• Hyperthyroidism 

What are the most serious risks of theophylline for dogs?

Serious side effects in dogs taking theophylline are rare but possible. Serious effects are more common when dogs are receiving high doses of theophylline. 

Serious effects of theophylline treatment may include: 

• Muscle tremors

• Seizures

• Collapse

If your dog has serious side effects with theophylline, stop giving the medication and seek veterinary care. Seek emergency care for any seizure. 

Do not give theophylline to dogs with a known history of epilepsy (seizures). 

Does theophylline interact with any other dog medications?

Yes, theophylline can interact with a number of other medications. So it’s important for your veterinarian to be familiar with all medications your dog takes, including prescription and over-the-counter medications as well as supplements. 

Medications that are known to interact with theophylline include:

• Activated charcoal

• Cimetidine 

• Clindamycin

• Diuretics

• Erythromycin 

• Fluconazole

• Fluoroquinolones

• Levothyroxine

• Methotrexate 

• Phenobarbital

• Prednisone (and other corticosteroids)

• Phenytoin

• Rifampin

What should you do if your dog misses a dose of theophylline?

If your dog misses a dose of theophylline, give the missed dose as soon as possible. If it’s almost time for your dog’s next dose, skip the missed dose and resume your dog’s regular dosing schedule. Do not give a double dose of theophylline since it could lead to an overdose. 

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Written by:

Catherine Barnette, DVM

Catherine Barnette, DVM, is a small animal veterinarian with 14 years of experience providing preventive care, medical workups, and surgical services in a number of general veterinary practices. She also served on her county's board of health for several years and taught biology laboratories for college students.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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