Methocarbamol Oral Dosing for Horses
The recommended oral dose of methocarbamol for horses is 15-30 mg/kg body weight, which typically translates to 5-15 grams per horse depending on size and clinical situation. 1, 2
Dosage Recommendations
- The standard single oral dose used in regulatory guidelines for performance horses is 5 grams 1
- Higher doses of 15 grams are commonly used in clinical practice for more severe muscle disorders 1, 2
- Oral bioavailability of methocarbamol in horses ranges from 43.2-72.8% (median 54.4%) 2
- Peak plasma concentrations following oral administration occur within 15-45 minutes 3
Clinical Considerations
- Methocarbamol is primarily used for treating skeletal muscle disorders in horses, including rhabdomyolysis (also known as "tying-up") 1, 4
- The terminal half-life after oral administration ranges from 2.21-4.88 hours (median 2.89 hours) 2
- When administered at doses higher than 5 grams, extended withdrawal times should be considered for competition horses 1
- Mild to moderate sedation/depression is a common side effect observed in horses receiving oral methocarbamol 3
Administration Protocol
- For acute muscle spasms or mild rhabdomyolysis: 5 grams orally per adult horse 1
- For more severe cases: 15 grams orally, which may be repeated as needed based on clinical response 1, 2
- Higher doses (50-100 mg/kg or approximately 25-50 grams for a 500 kg horse) have been studied but may cause increased sedation 3
Important Considerations
- No significant cardiovascular or respiratory effects have been observed even with high doses (up to 100 mg/kg orally) 3
- When administered concurrently with phenylbutazone, no significant pharmacokinetic interactions were observed 1
- Methocarbamol can be detected in plasma for approximately 24 hours after oral administration 2
- For compounded oral suspensions, proper pharmaceutical formulation is important for consistent bioavailability 4