Prosoma 500 mg (carisoprodol), also known as Soma. It is a muscle relaxant that reduces pain sensations between the nerves and the brain. Soma is used to treating bone and muscular disorders such as pain or injury, as well as rest and physical therapy. Prosoma 350 mg (carisoprodol), also known as Soma. It is a muscle relaxant that reduces pain sensations between the nerves and the brain. Soma is used to treating bone and muscular disorders such as pain or injury, as well as rest and physical therapy.