An aval white pill with R180 on it. What is it?

Not medical advice: A white, oval pill with the imprint “R180” is 4 mg of tizanidine hydrochloride, which is used in the treatment of muscle spasms and cluster headaches. It is considered a skeletal muscle relaxant. Side effects include dry mouth, somnolence, fatigue, dizziness, urinary tract and other infections, vomiting, speech disorders, blurred vision, increased frequency of urination and constipation.
Updated on Monday, February 06 2012 at 10:44AM EST