How many days should Robaxin (Methocarbamol) 500 be taken for?

Methocarbamol (Robaxin) 500 mg Treatment Duration

Methocarbamol 500 mg should be taken for 2-3 days at the initial dosage of 3 tablets four times daily (6 grams/day), followed by a maintenance dosage of 2 tablets four times daily (4 grams/day) for up to 8 days total, with treatment discontinued once pain relief is achieved. 1

Initial Dosing Regimen

• For adults, the FDA-approved initial dosage for methocarbamol 500 mg is 3 tablets four times daily (6 grams/day) 1
• Six grams daily is recommended for the first 48 to 72 hours of treatment 1
• For severe conditions, up to 8 grams per day may be administered initially 1

Maintenance Dosing

• After the initial 48-72 hours, the dosage can usually be reduced to approximately 4 grams per day (2 tablets four times daily) 1
• Treatment should be continued until pain relief is achieved, with a maximum treatment duration of about 8 days 2

Treatment Duration Considerations

• In clinical studies of methocarbamol for acute low back pain, treatment was discontinued as soon as a pain-free state was achieved 2
• In one randomized controlled study, 44% of patients taking methocarbamol were able to discontinue treatment early due to complete pain relief, compared to only 18% in the placebo group 2
• The study protocol allowed for up to 8 days of treatment, but encouraged discontinuation once pain relief was achieved 2

Efficacy and Monitoring

• Methocarbamol is effective for treating low back pain associated with myofascial components and muscle spasms 2
• Improvements in mobility (measured by fingertip-to-floor distance and Schober's test) were significantly better in patients treated with methocarbamol compared to placebo 2
• Monitor for symptom improvement and discontinue treatment once pain relief is achieved 2

Safety Considerations

• Methocarbamol is generally well-tolerated with few severe adverse effects reported in clinical studies 2
• Caution should be exercised when combining methocarbamol with alcohol, as the combination can lead to enhanced central nervous system depression due to interactive sedative-hypnotic properties 3
• Common side effects include drowsiness, dizziness, and headache 2

Important Pitfalls to Avoid

• Do not continue treatment longer than necessary once pain relief is achieved 2
• Avoid concurrent use with alcohol due to potential fatal interactions from combined central nervous system depression 3
• Be aware that therapeutic blood concentrations of methocarbamol are 24 to 41 micrograms/mL; higher concentrations may increase risk of side effects 3