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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

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

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 →

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

Educational reference only

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.

Educational reference only

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.

Educational reference only

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

Plumb's Veterinary Drug Handbook
Withrow & MacEwen's Small Animal Clinical Oncology
Merck Veterinary Manual
NRC Nutrient Requirements of Dogs and Cats
Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

ASPCA Animal Poison Control Center Guidelines
AAHA Diabetes Management Guidelines
ASPCA Poison Control Guidelines
RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

EPIC Study (J Vet Intern Med 2016)
JVIM FAT CAT Study

Regulatory & approvals — 1

CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

Washington State University VCPL MDR1 Database

Related medicines

Other medicines in the same class (Methylxanthine Bronchodilator).

Theophylline

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

dogcat