Use of gabapentin for attenuation of symptoms following rapid opiate detoxification (ROD) -correlation with neurophysiological parameters

Abstract Rapid opiate detoxification (ROD) is a technique whereby the opiate-dependent patient is withdrawn acutely, under anesthesia, from the opioid. Following detoxification, patients experience severe back pain and restlessness often accompanied by a restless-leg-syndrome. We evaluated gabapentin given immediately following detoxification to attenuate these symptoms. In addition, we evaluated the use of the somatosensory-evoked potential (SEP) as a parameter to quantitate pain responses. Patients (n=21; mean age 32.5 ± 7 SD; 12 males, 9 females) underwent ROD with naltrexone (2 x 50 mg) during propofol anesthesia and artificial ventilation (IPPV). Sympathetic overshoot was attenuated by clonidine, and increased bowl movement was managed by continuous i.v. somatostatin. Back pain, restlessness, and restless-leg-syndrome were treated with gabapentin (1200 mg) in the ICU. Efficacy was assessed by the patient’s subjective ratings of restlessness (0-4). In addition, measurements of amplitude (μV), latency (ms) of late N 100 -peak of the somatosensory evoked potential (SEP), and tolerance to an increased electrical nociceptive stimulus (mA) to the forearm were performed. Data were compared to pre-treatment control and to the period shortly after detoxification. From a mean of 8.4 ± 2.5 μV, N 100 -peak increased to a mean of 12.3μV ± 3.3 (p  The sudden displacement of the opiate from its receptor site induced by naltrexone, resulted in a post inhibitory SEP overshoot with an increase in nociceptive afferent volleys, and a lowering in pain threshold. This was associated with back pain, limb thrashing and a restless-leg-syndrome, all of which could be attenuated by gabapentin. The amplitude of late N 100 -peak parameter appears to be a potential candidate to quantify the increase of nociception in such patients.