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Dantrolene

Prescription
Direct-acting skeletal muscle relaxant
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
1 documented
Formulations
2

Mechanism of action

Acts directly on skeletal muscle by interfering with calcium release from the sarcoplasmic reticulum via ryanodine receptor inhibition, reducing muscle contraction without affecting neuromuscular transmission

At a glance

Class
Direct-acting skeletal muscle relaxant
Schedule
Prescription
Storage
Below 25°C, protect from light; reconstituted IV solution use within 6 hours

Dosing

🐕

Dog

Malignant hyperthermia, muscle spasticity, post-anesthetic muscle rigidity
Dose
1–5 mg/kg
Route
IV (for MH emergency), PO (for chronic spasticity)
Frequency
Q15 min IV (MH) until resolved; TID (PO)
Max dose
10 mg/kg (IV for MH)/dose; 20 mg/kg (IV for MH)/day
Duration: Until hyperthermia resolves (IV); chronic for spasticity
🐈

Cat

Urethral spasm (feline urethral obstruction adjunct), muscle spasticity
Dose
0.5–2 mg/kg
Route
PO
Frequency
BID to TID
Max dose
25 mg/dose; 75 mg/day
Duration: 3–5 days post-unblocking
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

💊

Capsule — 1

Strength
25mg
💉

Powder for injection — 1

Strength
20mg/vial

Storage

Below 25°C, protect from light; reconstituted IV solution use within 6 hours

Safety

Use with caution

  • Hepatic disease
    Hepatotoxicity is a significant concern
  • Cardiac or pulmonary disease
    May cause cardiovascular collapse with concurrent verapamil

Adverse effects

Common
Muscle weakness
Sedation
GI upset
Serious
Hepatotoxicity (potentially fatal)
Respiratory depression
Cardiovascular collapse (with verapamil)

Monitoring parameters

Hepatic enzymes (baseline and periodic)Muscle strengthBody temperature (MH)Respiratory function
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 →

Interactions

Major — 1

Verapamil
major
Both have negative inotropic effects. Dantrolene reduces intracellular calcium release; verapamil blocks calcium channels. Combined: hyperkalemia and cardiovascular collapse documented.
Management: Avoid combination. If dantrolene needed for malignant hyperthermia in patient on verapamil, prepare for aggressive cardiovascular support.
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 →

Brands

International

Dantrium
Par Pharmaceutical
Revonto
US WorldMeds

India

Dantrolene Capsules
Samarth Pharma (import)

FAQs

Frequently asked questions

›What is Dantrolene?
Dantrolene is a direct-acting skeletal muscle relaxant used in pets. Acts directly on skeletal muscle by interfering with calcium release from the sarcoplasmic reticulum via ryanodine receptor inhibition, reducing muscle contraction without affecting neuromuscular transmission
›What is Dantrolene used for in pets?
Dantrolene is used in veterinary medicine for: Malignant hyperthermia, muscle spasticity, post-anesthetic muscle rigidity; Urethral spasm (feline urethral obstruction adjunct), muscle spasticity.
›What is the Dantrolene dose for dogs?
For dogs, Dantrolene is typically dosed as follows — Malignant hyperthermia, muscle spasticity, post-anesthetic muscle rigidity: 1–5 mg/kg IV (for MH emergency)/PO (for chronic spasticity) Q15 min IV (MH) until resolved; TID (PO). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Dantrolene dose for cats?
For cats, Dantrolene is typically dosed as follows — Urethral spasm (feline urethral obstruction adjunct), muscle spasticity: 0.5–2 mg/kg PO BID to TID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Dantrolene?
Common: Muscle weakness, Sedation, GI upset. Serious (call your vet immediately): Hepatotoxicity (potentially fatal), Respiratory depression, Cardiovascular collapse (with verapamil).
›Does Dantrolene need a prescription?
Yes. Dantrolene is a prescription medication and should only be administered under veterinary supervision.
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 →

References

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
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