Maximum Dose of Robaxin (Methocarbamol) Every 4 Hours
The maximum dose of methocarbamol is 1.5 grams (two 750 mg tablets) every 4 hours, with a total daily maximum of 8 grams for severe conditions during the first 48-72 hours of treatment. 1
Standard Dosing Protocol
Initial Treatment Phase (First 48-72 Hours)
- For 750 mg tablets: 2 tablets every 4 hours (1,500 mg per dose) 1
- For 500 mg tablets: 3 tablets every 4 hours (1,500 mg per dose) 1
- Total daily dose: 6 grams per day is recommended for most acute conditions 1
- Maximum daily dose for severe conditions: 8 grams per day may be administered during the initial treatment period 1
Maintenance Dosing (After 72 Hours)
- For 750 mg tablets: 1 tablet every 4 hours OR 2 tablets three times daily 1
- For 500 mg tablets: 2 tablets four times daily 1
- Total daily maintenance dose: Approximately 4 grams per day 1
Critical Safety Considerations
Absolute Contraindications
- Concurrent alcohol use is strictly contraindicated due to potentially fatal CNS depression from the combined sedative-hypnotic properties of both substances 2
- Blood ethanol levels as low as 135 mg/dL combined with therapeutic methocarbamol concentrations (257 micrograms/mL) have resulted in fatal outcomes 2
Monitoring Requirements
- Therapeutic methocarbamol concentrations are reported to be 24-41 micrograms/mL 2
- The case literature documents toxic concentrations at 257 micrograms/mL in blood, with tissue accumulation reaching 459 micrograms/g in liver 2
- Monitor for excessive sedation, particularly when approaching maximum dosing thresholds 1, 2
Common Pitfalls to Avoid
- Never exceed 1.5 grams per single dose when dosing every 4 hours 1
- Do not continue 8 gram daily dosing beyond 72 hours without reassessing the clinical indication 1
- Screen all patients for alcohol use before prescribing, as the interaction can be lethal even at moderate alcohol levels 2
- Avoid combining with other CNS depressants that may potentiate sedative effects 2