Adult Methocarbamol Dosage Every six hours, a normal dose of 1,000 mg to 2,000 mg is taken. The optimum dose is also affected by age and other medical problems. Before prescribing methocarbamol, a healthcare professional will provide patients precise instructions and pharmacological information. If the patient does not understand these instructions or if they fail to take the medication as prescribed, they may be at risk for serious side effects. Methocarbamol's mechanism of action is unknown. It appears to work by weakening muscles and preventing them from contracting. This effect increases the rate at which the brain receives messages from the heart and lungs and reduces pain associated with osteoarthritis. The drug should not be given to people who are allergic to methocarbamol or any of its ingredients. Methocarbamol comes in tablet form and can be taken by mouth or applied to the skin. It is usually taken three times a day after meals with water. The dosage is based on your weight so one dose will vary depending on how many grams you weigh. For example, a person who weighs 70 kg (154 lbs) would need 70 kg x 3 = 210 mg/day. The drug should be administered for no longer than 10 days unless another clinical indication exists for this length of time. 1000 mg of Robaxin is a standard dose used to treat chronic pain.