Use of gabapentin for attenuation of symptoms following rapid opiate detoxification (ROD)--correlation with neurophysiological parameters--.
Rapid opiate detoxification (ROD) is a technique whereby the opiate-dependent patient is withdrawn acutely, under anesthesia, from the opioid.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 (microV), latency (ms) of late N100-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 microV, N100-peak increased to a mean of 12.3 microV +/- 3.3 (p < 0.005) following opioid detoxification. Gabapentin reduced amplitude height to a mean of 3.5 +/- 1.5 microV. Also, tolerance to nociceptive stimulus, which had dropped to 4.4 mA, increased to 12.5 mA (p < 0.01), while intensity for restlessness and thrashing of limbs dropped from 3.2 to 1.2 (p < 0.05). 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 N100-peak parameter appears to be a potential candidate to quantify the increase of nociception in such patients.
Freye
E
E
Clinics of Vascular surgery and renal transplantation, University of Düsseldorf, Germany. enno.freye@uni-duesseldorf.de
Levy
J V
JV
Partecke
L
L
D000085:Acetates / Q000627:therapeutic use*; D000328:Adult; D000588:Amines; D000758:Anesthesia; D018686:Anesthetics, Intravenous; D003509:Cyclohexanecarboxylic Acids; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000627:therapeutic use*; D005260:Female; D000077206:Gabapentin; D006556:Heroin Dependence / Q000534:rehabilitation / Q000628:therapy*; D006727:Hormone Antagonists / Q000627:therapeutic use; D006801:Humans; D008274:Magnesium / Q000627:therapeutic use; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008691:Methadone / Q000627:therapeutic use; D009271:Naltrexone / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000627:therapeutic use; D009294:Narcotics / Q000627:therapeutic use; D011188:Potassium / Q000097:blood; D015742:Propofol; D012148:Restless Legs Syndrome / Q000188:drug therapy / Q000209:etiology; D013004:Somatostatin / Q000627:therapeutic use; D013375:Substance Withdrawal Syndrome / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D014882:Water-Electrolyte Balance / Q000187:drug effects; D005680:gamma-Aminobutyric Acid
D000085:Acetates; D000588:Amines; D018686:Anesthetics, Intravenous; D003509:Cyclohexanecarboxylic Acids; D018691:Excitatory Amino Acid Antagonists; D006727:Hormone Antagonists; D009292:Narcotic Antagonists; D009294:Narcotics; D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D009271:Naltrexone; D000077206:Gabapentin; D008274:Magnesium; D011188:Potassium; D008691:Methadone; D015742:Propofol