Methocarbamol (Robaxan) Dosing
For adults, start with 1500 mg four times daily (6 grams/day) for the first 48-72 hours, then reduce to 1000-1500 mg four times daily (4 grams/day) for maintenance. 1
Initial Dosing (First 48-72 Hours)
- Standard initial dose: 6 grams per day divided into four doses 1
- For 500 mg tablets: 3 tablets four times daily 1
- For 750 mg tablets: 2 tablets four times daily 1
- For severe conditions: up to 8 grams per day may be administered during the initial treatment period 1
Maintenance Dosing (After 48-72 Hours)
- Reduce to approximately 4 grams per day once the acute phase has passed 1
- For 500 mg tablets: 2 tablets four times daily 1
- For 750 mg tablets: 1 tablet every 4 hours, or 2 tablets three times daily 1
Clinical Efficacy Evidence
- Methocarbamol at 1500 mg four times daily was effective in approximately 60% of patients with painful muscle spasm, compared to only 30% with placebo (p < 0.01) 2
- In acute low back pain, 44% of methocarbamol-treated patients achieved complete pain relief allowing early discontinuation, versus only 18% with placebo (p < 0.0001) 3
- Treatment duration should continue until pain-free state is achieved, typically up to 8 days 3
Important Safety Considerations
- Methocarbamol is contraindicated with alcohol consumption due to additive CNS depression that can be fatal 4
- Common adverse effects include headache and nausea, but severe adverse events are rare (occurred in only 5 patients in clinical trials) 3
- Side effects occur at similar rates to placebo when used at therapeutic doses 2
- Methocarbamol remains the only approved muscle relaxant in Europe following EMA restrictions on other agents like tetrazepam 3