Theophylline Drug Handout

What is Theophylline?

Theophylline is a medication closely related to caffeine. It relaxes the muscles in the airways (bronchodilator), increases the strength of the muscles involved with breathing, and improves how well mucus and debris are removed from the lungs.


  • Chronic bronchitis and other airway diseases in dogs
  • Feline asthma and bronchitis
  • Increases heart rate in cases of sick sinus syndrome and heart block
  • Decreases the risk for collapse in cases of vasovagal or tussive syncope (fainting)

Adverse Effects

Please contact CVCA should any of these symptoms be noted

  • Caffeine like side effects (anxiety, restlessness, panting)
  • Decreased appetite, vomiting or diarrhea
  • Increased heart rate and risk for arrhythmias
  • Small increased risk for seizures in patients with preexisting epilepsy

Client Information

  • Best if given with food to avoid stomach upset
  • Comes in tablet form and liquid suspension
  • Very commonly used in conjunction with cardiac medications
  • Does not require any specific monitoring

Interactions with Other Drugs

Standard Dosage Forms

Synonyms: (Theophylline ER, Theo-dur, Slo-Bid)