A muscle relaxant or muscle relaxer is a drug which decreases muscle tone and may be prescribed to address muscle pain, cramps, strain, and/or tightness. There are two groups of prescription medications: antispasmodics and antispastics.
Antispasmodics mainly address sudden and involuntary muscle contractions by causing sedation and preventing pain signals to reach the brain. Some of antispasmodics include carisoprodol, chlorzoxazone, metaxalone, orphenadrine, and tizanidine.
Antispastics mainly address muscle stiffness or rigidity which may lead to movement difficulties. The examples include baclofen, dantrolene, and diazepam.