Home/Medicines/Dextromethorphan

Dextromethorphan

Antitussive (Non-Opioid)

Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

2 available

Interactions

2 documented

Formulations

Mechanism of action

NMDA receptor antagonist and sigma-1 receptor agonist that suppresses the cough reflex at the level of the brainstem cough center. Does not act on mu-opioid receptors; no analgesic or addictive properties.

At a glance

Class

Antitussive (Non-Opioid)

Schedule

OTC

Storage

Store at room temperature; check product for xylitol before use in dogs

Dosing

🐕

Dog

Mild antitussive for non-productive cough

Dose

1–2 mg/kg

Route

Frequency

q6–8h

🐈

Cat

Cats cannot safely metabolize dextromethorphan; avoid use

Dose

—

Route

N, A

Frequency

N/A

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 — 2

Strength

—

Strength

—

Storage

Store at room temperature; check product for xylitol before use in dogs

Safety

Monitoring parameters

Cough responseSedation level

Educational reference only

Interactions

Contraindicated — 1

Selegiline (L-Deprenyl)

contraindicated

DXM has serotonergic properties + selegiline is MAO inhibitor. Risk of serotonin syndrome.

Management: NEVER combine. Use alternative antitussive.

Major — 1

Fluoxetine

major

Fluoxetine inhibits CYP2D6 (which metabolizes DXM) AND both are serotonergic (DXM: NMDA antagonist + sigma-1 agonist + weak SRI). Combined: serotonin syndrome risk and DXM accumulation.

Management: Avoid. If antitussive needed with SSRI, use non-serotonergic option (hydrocodone, butorphanol).

Educational reference only

Brands

Other markets

Robitussin DM (combination)

Delsym

FAQs

Frequently asked questions

›What is Dextromethorphan?

Dextromethorphan is a antitussive (non-opioid) used in pets. NMDA receptor antagonist and sigma-1 receptor agonist that suppresses the cough reflex at the level of the brainstem cough center. Does not act on mu-opioid receptors; no analgesic or addictive properties.

›What is Dextromethorphan used for in pets?

Dextromethorphan is used in veterinary medicine for: Mild antitussive for non-productive cough; Cats cannot safely metabolize dextromethorphan; avoid use.

›What is the Dextromethorphan dose for dogs?

For dogs, Dextromethorphan is typically dosed as follows — Mild antitussive for non-productive cough: 1–2 mg/kg PO q6–8h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Dextromethorphan dose for cats?

For cats, Dextromethorphan is typically dosed as follows — Cats cannot safely metabolize dextromethorphan; avoid use: undefined undefined N/A N/A. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›Does Dextromethorphan need a prescription?

Dextromethorphan is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.

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