Pain O Soma 500 mg is believed to affect GABA receptors in the brain and, in doing so, it changes how nerve signals are sent.The drug is a central nervous system depressant. This means that people may feel drowsy or intoxicated when using Soma -particularly at higher doses.Some of the side effects of Soma can include sedation, dizziness and headaches. If someone takes too much Soma, they can overdose.Signs of a Soma overdose can include confusion, problems breathing, hallucinations, muscle stiffness, uncontrolled eye movements and weakness of the arms and legs.