From the FDA Drug Label
DOSAGE AND ADMINISTRATION Methocarbamol, 500 mg — Adults: Initial dosage: 3 tablets q.i.d. Maintenance dosage: 2 tablets q.i.d. Methocarbamol, 750 mg — Adults: Initial dosage: 2 tablets q.i.d. Maintenance dosage: 1 tablet q.4h. or 2 tablets t.i.d. Six grams a day are recommended for the first 48 to 72 hours of treatment. (For severe conditions 8 grams a day may be administered). Thereafter, the dosage can usually be reduced to approximately 4 grams a day. The recommended dose and frequency of Robaxin (methocarbamol) are:
- Initial dosage:
- 500 mg: 3 tablets q.i.d. (four times a day)
- 750 mg: 2 tablets q.i.d. (four times a day)
- Maintenance dosage:
- 500 mg: 2 tablets q.i.d. (four times a day)
- 750 mg: 1 tablet q.4h. (every 4 hours) or 2 tablets t.i.d. (three times a day) The total daily dose is recommended to be 6 grams for the first 48 to 72 hours of treatment, and can be reduced to approximately 4 grams per day thereafter 1.
From the Research
Robaxin (methocarbamol) should be prescribed at a dose of 1500 mg four times daily for adults with muscle spasms, with a reduction to 750 mg every 4 hours or 1000 mg four times daily for maintenance therapy after 48-72 hours, as this regimen has been shown to be effective in clinical practice, although recent studies suggest that skeletal muscle relaxants may not improve outcomes more than placebo in patients with acute low back pain 2. The treatment usually begins with this higher dose for the first 48-72 hours, after which it can be reduced to 750 mg every 4 hours or 1000 mg four times daily for maintenance therapy.
- The maximum daily dose should not exceed 8000 mg.
- For elderly patients or those with liver or kidney issues, lower doses may be appropriate, as renal impairment can influence the pharmacokinetics of nonrenally eliminated drugs 3.
- Robaxin works as a central muscle relaxant by depressing the central nervous system, though its exact mechanism isn't fully understood.
- Common side effects include drowsiness, dizziness, and blurred vision, so patients should avoid driving or operating machinery until they know how the medication affects them.
- Robaxin should be taken with food if stomach upset occurs.
- Patients should not abruptly stop taking this medication without consulting their healthcare provider, and should inform their doctor about any other medications they're taking to avoid potential interactions. It's worth noting that a recent study found that skeletal muscle relaxants, including methocarbamol, do not improve outcomes more than placebo in patients with acute low back pain 2, but this should not preclude their use in clinical practice where they may still provide benefit for individual patients.