Theophylline is a multi-purpose medicine which mainly acts as a bronchodilator – in other words, it opens up the air passages in the lungs. It also has slight diuretic properties, meaning it makes a dog pass more water.

It also has the ability to increase the release of stomach acid and inhibit contractions of the uterus.

Recommended Dosage

Note: Do not give your dog theophylline unless it has been recommended by your vet, and always follow the vet’s exact dosing recommendations. The following information is provided as a general guideline only.

The medicine is usually given to dogs at a dosage of 4.5 – 6.8 mg/lb every 12 hours (twice daily), or 9 mg/lb once daily using 24-hour extended-release pills. During treatment the dog will need to be carefully monitored, both for the relief of symptoms, and for how well he tolerates the drug. The dosage should be adjusted carefully to balance the side effects with the effectiveness.

It’s best to give the medicine with food to help avoid vomiting.

The chart and calculator below should help you find the typical starting dose for your dog.
Theophylline dosage for dogs

Dog’s Weight In Pounds: Dosage In Mg:

Because the drug is not very soluble in fat, it may be necessary to dose by lean body weight in very overweight dogs.

Extended-release tablets are commonly used and tend to peak around 4 – 6 hours after administration in dogs, but the amount of active ingredient that will actually be received from human extended-release pills can vary. It is important that these pills are not chewed or crushed.

A liquid form sold under the trade name Elixophyllin is also available, containing 5.3 mg of theophylline per milliliter.

Liver Failure Warning: When treating dogs with liver failure, it is recommended that you reduce the dosage by half.


Aminophylline is a combination of theophylline and ethylenediamine. When given to dogs, it is often dosed at around 4.5 – 5 mg/lb three times daily for symptoms resulting from a mildly collapsed trachea (less than 50% collapsed). It is also sometimes used as adjunctive therapy for pulmonary edema and bronchoconstriction at a dosage of 1.8 – 4.5 mg/lb three times daily.

Example: A dog weighing 20 pounds would often be started on around 90 mg of theophylline, which would then be adjusted based on his response to the drug.

Is It Safe?

Unlike humans, dogs seem better able to handle higher blood-levels of theophylline. However dogs with the following conditions may not be suitable for treatment:

  • Heart, liver, or kidney disease
  • Seizure disorders
  • Hyperthyroidism
  • Stomach ulcers
  • High blood pressure
  • Hypoxia
  • Arrhythmia

Theophylline interacts with other medicines including some antibiotics, thyroid medication, furosemide, phenobarbital, and many more. Older dogs tend to take longer to clear the drug which should also be taken into account.

Pregnancy and Nursing: Theophylline should not be given to pregnant or nursing animals.

Safety Guidelines

To safely use this medicine, we recommend following these guidelines:

  • Do not use without approval from your vet
  • Do not give with any other medicines or supplements unless your vet gives you permission
  • Tell the vet about any illnesses or medical conditions affecting your dog
  • Use a reduced dosage in dogs with liver failure

Dogs with arrhythmia should be treated with caution and monitored carefully, as theophylline could make the condition worse.

What Is It Used For?

Theophylline is sometimes given to dogs to treat the following conditions:

  • Cough
  • Asthma
  • Bronchitis
  • Heart failure
  • Pulmonary edema
  • COPD (particularly pulmonary hypertension caused by COPD)


Side Effects

Not much is yet known about the adverse effects of this medicine, but the following effects are possible:

  • Anxiety
  • Insomnia
  • Vomiting
  • Diarrhea
  • Excessive hunger and/or thirst
  • Increased urination

Symptoms of nervous system excitement (such as anxiety and insomnia) and stomach upset tend to pass with repeated use and adjustment of the dosage.

Though toxicity in humans starts when blood levels of the drug rise above 20 mcg/mL, dogs are better able to tolerate higher levels. The most common symptom of overdose is a rapid heart rate, and apart from this, seizures, hyperthermia and arrhythmias are possible. Always seek emergency advice if you suspect an overdose, either by calling your vet or the ASPCA poison control hotline on (888) 426-4435.

One possible treatment option if seizures occur is to administer Valium (diazepam) intravenously, while keeping the airway open. Electrolytes, fluid and heart function will be closely monitored following an overdose. If body temperature begins to rise too high, phenothiazines may be given, while in the event of a rapid heart rate, propranolol can be used.


Plumb’s Veterinary Drugs