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Aminophylline

Prescription
Methylxanthine Bronchodilator
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Interactions
5 documented
Formulations
3

Mechanism of action

Salt of theophylline with ethylenediamine (about 80% theophylline by weight). Inhibits phosphodiesterase, increasing intracellular cAMP; antagonizes adenosine receptors. Causes bronchodilation, stimulates respiration, and has mild diuretic effects.

At a glance

Class
Methylxanthine Bronchodilator
Schedule
Prescription
Storage
Store at room temperature, protect from light and moisture

Dosing

🐕

Dog

Used for bronchospasm, collapsing trachea, and pulmonary edema (diuretic)
Dose
4–9 mg/kg
Route
PO, IV
Frequency
q8h (PO); slow IV infusion (acute)
🐈

Cat

Used for feline asthma (bronchospasm)
Dose
5 mg/kg
Route
PO, IV
Frequency
q8–12h

Formulations

💊

Other — 3

Strength
—
Strength
—
Strength
—

Storage

Store at room temperature, protect from light and moisture

Safety

Monitoring parameters

Serum theophylline levels (therapeutic 10–20 mcg/mL)Heart rate and rhythmRespiratory rateGI signs

Interactions

Major — 4

Enrofloxacin
major
Fluoroquinolones (especially enrofloxacin) inhibit CYP1A2 metabolism of theophylline (aminophylline = theophylline salt), increasing theophylline levels 50-100%. Risk of seizures and cardiac arrhythmias.
Management: Reduce aminophylline/theophylline dose by 30-50% when adding enrofloxacin. Monitor for signs of theophylline toxicity (restlessness, tachycardia, seizures). Monitor theophylline levels if available.
Ciprofloxacin
major
Ciprofloxacin inhibits CYP1A2 metabolism of theophylline (aminophylline), increasing levels and toxicity risk (seizures, arrhythmias).
Management: Reduce aminophylline dose by 30-50%. Monitor theophylline levels if available.
Caffeine
major
Both are methylxanthines with same mechanism (PDE inhibition, adenosine antagonism). Additive toxicity: seizures, tachyarrhythmias, GI irritation.
Management: Do not combine. If switching between methylxanthines, allow washout.
Fluvoxamine
major
Fluvoxamine is the most potent SSRI inhibitor of CYP1A2, which metabolizes theophylline. Increases theophylline levels 3-fold, causing seizures and cardiac arrhythmias.
Management: NEVER combine. If SSRI needed with theophylline/aminophylline, use sertraline (minimal CYP1A2 effect).

Moderate — 1

Phenobarbital
moderate
Phenobarbital induces CYP1A2, increasing theophylline metabolism and reducing therapeutic levels.
Management: May need to increase aminophylline dose. Monitor theophylline levels and clinical response.

Brands

Other markets

Phyllocontin
Truphylline

FAQs

Frequently asked questions

›What is Aminophylline?
Aminophylline is a methylxanthine bronchodilator used in pets. Salt of theophylline with ethylenediamine (about 80% theophylline by weight). Inhibits phosphodiesterase, increasing intracellular cAMP; antagonizes adenosine receptors. Causes bronchodilation, stimulates respiration, and has mild diuretic effects.
›What is Aminophylline used for in pets?
Aminophylline is used in veterinary medicine for: Used for bronchospasm, collapsing trachea, and pulmonary edema (diuretic); Used for feline asthma (bronchospasm).
›What is the Aminophylline dose for dogs?
For dogs, Aminophylline is typically dosed as follows — Used for bronchospasm, collapsing trachea, and pulmonary edema (diuretic): 4–9 mg/kg PO/IV q8h (PO); slow IV infusion (acute). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Aminophylline dose for cats?
For cats, Aminophylline is typically dosed as follows — Used for feline asthma (bronchospasm): 5 mg/kg PO/IV q8–12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Aminophylline need a prescription?
Yes. Aminophylline is a prescription medication and should only be administered under veterinary supervision.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Related medicines

Other medicines in the same class (Methylxanthine Bronchodilator).

Theophylline
Rx
Inhibits phosphodiesterase, increasing intracellular cAMP; relaxes bronchial smooth muscle, stimulates respiratory drive, and mildly improves diaphragmatic contractility
dogcat