Ketamine has also been shown to have positive effects on chronic pain syndromes. Though the exact process has not been mapped out, ketamine influences pain in a variety of ways. Primarily, ketamine acts as an N-methyl-D-aspartate (NMDA) receptor inhibitor. Neurogenic pain is greatly influenced by the NMDA-receptor system and, “antagonizing this system may be a useful way to obtain better pain control.” Ketamine also has anti-inflammatory effects as well as enhances the descending inhibition of pain. Studies have shown that infusion from 4-14 days can lead to long-term analgesic effects for up to 3 months. Some side effects include, “psychedelic symptoms (hallucinations, memory defects, panic attacks),  somnolence, cardiovascular stimulation and, in a minority of patients, hepatoxicity.” However, some studies have shown benzodiazepines are able to reduce the psychotropic side effects.