Methocarbamol

Methocarbamol, sold under the brand name Robaxin among others, is a medication used for short-term musculoskeletal pain.^[3][4] It may be used together with rest, physical therapy, and pain medication.^[3][5][6] It is less preferred in low back pain.^[3] It has limited use for rheumatoid arthritis and cerebral palsy.^[3][7] Effects generally begin within half an hour.^[3] It is taken by mouth or injection into a vein.^[3]

Common side effects include headaches, sleepiness, and dizziness.^[3][8] Serious side effects may include anaphylaxis, liver problems, confusion, and seizures.^[4] Use is not recommended in pregnancy and breastfeeding.^[3][4] Because of the risk of injury, skeletal muscle relaxants should generally be avoided in geriatric patients.^[3] Methocarbamol is a centrally acting muscle relaxant.^[3] How it works is unclear, but it does not appear to affect muscles directly.^[3]

Methocarbamol was developed in 1956 in the laboratories of A. H. Robins (later acquired by Pfizer). Studies were directed towards the development of propanediol derivatives which possessed muscle relaxant properties superior to those of mephenesin, which had low potency and a short duration of action.^[9] It was approved for medical use in the United States in 1957.^[3] It is available as a generic medication.^[3][4] In 2023, it was the 121st most commonly prescribed medication in the United States, with more than 5 million prescriptions.^[10][11] Methocarbamol is available in a fixed-dose combination with ibuprofen as methocarbamol/ibuprofen (sold under the brand name Summit Ultra).^[12]