Methocarbamol Dosage and Administration. Methocarbamol Tablets, USP, 500 mg – Adults: Initial dosage: 3 tablets four times daily Maintenance dosage: 2 tablets four times daily. Methocarbamol Tablets, USP, 750 mg – Adults: Initial dosage: 2 tablets four times daily Maintenance dosage: 1 tablet every 4 hours or 2 tablets three times daily. Six grams a day are recommended for the first 48 to. Methocarbamol is an inexpensive drug used to treat pain and stiffness in muscles caused by strains, sprains, or injury. It is slightly less popular than comparable drugs. It is available in generic and brand versions. Generic methocarbamol is covered by most Medicare and insurance plans, but some pharmacy coupons or cash prices may be lower. Applies to methocarbamol: oral tablet. Other dosage forms: injection solution; Side effects requiring immediate medical attention. Along with its needed effects, methocarbamol may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Check with your doctor immediately if any of the following side effects occur while. Dosage for vertigo. Adult dosage (ages 18–64 years): Typical dosage: 25–100 mg per day, taken in divided doses. Dosage increases: Your doctor will decide the dose that’s right for you. They.