A muscle relaxant is a drug effective to relax muscles. Consumption before bedtime causes muscle relaxation which can cause sleep apnea and snoring. Some muscle relaxants are also prescribed in the adjuvant treatment of painful muscle spasms during spinal disorders such as stiff neck, back pain sitting at the height of the dorsal vertebrae (back pain) and lumbar spine (low back pain), or conditions in consecutive trauma. Alcohol also causes a muscle relaxant effect: this is the reason why alcohol consumption in the evening often leads nocturnal snoring.
Moreover, the muscle relaxation of the walls of the pharynx promotes sleep apnea. This is one good reason to avoid drinking alcohol before going to bed.