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Theophylline

Prescription

Methylxanthine bronchodilator

Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

3 available

Interactions

1 documented

Formulations

Mechanism of action

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

At a glance

Class

Methylxanthine bronchodilator

Schedule

Prescription

Storage

Store below 25°C; do not crush sustained-release tablets

Dosing

🐕

Dog

Bronchospasm / Chronic bronchitis / Collapsing trachea

Dose

5–10 mg/kg

Route

Frequency

BID (standard release) or SID (extended release)

Max dose

500 mg/dose; 1000 mg/day

Duration: Long-term for chronic conditions

🐈

Cat

Feline asthma / Chronic bronchitis

Dose

4–8 mg/kg

Route

Frequency

SID (evening; extended release) to BID

Max dose

50 mg/dose; 100 mg/day

Duration: Long-term; cats metabolize slower than dogs

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

💊

Tablet (sustained release) — 3

Strength

100mg

Available in India

Strength

200mg

Available in India

Strength

300mg

Available in India

Storage

Store below 25°C; do not crush sustained-release tablets

Safety

Absolute contraindications — do not use

Active seizure disorder
Can lower seizure threshold

Use with caution

Cardiac arrhythmias
May worsen tachyarrhythmias
Gastric ulceration
Increases gastric acid secretion

Adverse effects

Common

Restlessness

Tachycardia

GI upset

Polyuria/polydipsia

Serious

Seizures (toxicity)

Cardiac arrhythmias

Vomiting (overdose)

Monitoring parameters

Serum theophylline levels (therapeutic: 10–20 mcg/mL)Heart rateRespiratory rate

Educational reference only

Interactions

Major — 1

Enrofloxacin

major

Fluoroquinolones inhibit hepatic metabolism of theophylline, causing toxic accumulation

Management: Reduce theophylline dose by 30-50% if fluoroquinolone is required. Monitor for tachycardia, restlessness, vomiting.

Educational reference only

Brands

International

Theo-Dur

Key Pharma

India

Deriphyllin

Franco-Indian

Theodrip

Neon Labs

FAQs

Frequently asked questions

›What is Theophylline?

Theophylline is a methylxanthine bronchodilator used in pets. Inhibits phosphodiesterase, increasing intracellular cAMP; relaxes bronchial smooth muscle, stimulates respiratory drive, and mildly improves diaphragmatic contractility

›What is Theophylline used for in pets?

Theophylline is used in veterinary medicine for: Bronchospasm / Chronic bronchitis / Collapsing trachea; Feline asthma / Chronic bronchitis.

›What is the Theophylline dose for dogs?

For dogs, Theophylline is typically dosed as follows — Bronchospasm / Chronic bronchitis / Collapsing trachea: 5–10 mg/kg PO BID (standard release) or SID (extended release). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Theophylline dose for cats?

For cats, Theophylline is typically dosed as follows — Feline asthma / Chronic bronchitis: 4–8 mg/kg PO SID (evening; extended release) to BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What are the side effects of Theophylline?

Common: Restlessness, Tachycardia, GI upset, Polyuria/polydipsia. Serious (call your vet immediately): Seizures (toxicity), Cardiac arrhythmias, Vomiting (overdose).

›Does Theophylline need a prescription?

Yes. Theophylline is a prescription medication and should only be administered under veterinary supervision.

›When should Theophylline not be used?

Do not use Theophylline if: Active seizure disorder.

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).

Aminophylline

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.

dogcat