tizanidine

Tizanidine (trade names Relentus from Beximco Pharma, Zanaflex, Sirdalud) is a drug that is used as a muscle relaxant. It is a centrally acting α2 adrenergic agonist. It is used to treat the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis, ALS, spastic diplegia, back pain, or certain other injuries to the spine or central nervous system. It is also prescribed off-label for migraine headaches, as a sleep aid, and as an anticonvulsant. It is also prescribed for some symptoms of fibromyalgia.
Tizanidine has been found to be as effective as other antispasmodic drugs and is more tolerable than baclofen and diazepam. Tizanidine can be very strong even at the 2mg dose and may cause hypotension, so caution is advised when it is used in patients who have a history of orthostatic hypotension, or when switching from gel cap to tablet form and vice versa.
Tizanidine can occasionally cause liver damage, generally the hepatocellular type. Clinical trials show that up to 5% of patients treated with tizanidine had elevated liver function test values, though symptoms disappeared upon withdrawal of the drug. Care should be used when first beginning treatment with tizanidine with regular liver tests for the first 6 months of treatment. As of 2015 the cost for a typical month of medication in the United States is 100 to 200 USD.