Anesthesia-assisted opioid withdrawal, offered as quicker and easier than other rapid detoxification methods, was recently found to be comparable on several measures, but with greater risk for life-threatening adverse events. A randomized trial comparing anesthesia-, buprenorphine(Drug information on buprenorphine)- (Subutex) and clonidine(Drug information on clonidine)- (Catapres) assisted heroin detoxification found similarity in withdrawal symptom severity, low rates of inpatient program completion and high proportion of follow-up opioid-positive urine tests (Collins et al., 2005). While no detoxification procedure appeared "painless" or to facilitate program compliance or long-term abstinence, the anesthesia- and buprenorphine-assisted protocols were superior to the clonidine program in facilitating the naltrexone(Drug information on naltrexone) (ReVia) induction to rapidly counter opioid effect. The anesthesia-assisted protocol was distinct, however, in that three of 35 patients experienced serious adverse events.
One patient developed severe pulmonary edema and aspiration pneumonia approximately 14 hours after extubation. That patient subsequently admitted to a history of complicated pneumonia and possible obstructive sleep apnea; both of which were added to the exclusionary criteria for potential participants. A second patient who had concealed a history of bipolar illness developed a mixed bipolar state with suicidal ideation that necessitated rehospitalization five days after anesthesia.
The third patient had not disclosed a previous episode of diabetic ketoacidosis during screening and after anesthesia had uncontrolled glucose serum levels and developed ketoacidosis two days later. The investigators attributed the falsifying of medical or psychiatric histories in the screening interviews to patients hoping to be selected for anesthesia due to their expectation that it would obviate the severe discomfort of opioid withdrawal.
Costing as much as $15,000 and not covered by health insurance, according to the investigators, the anesthesia-assisted procedure is promoted to the well-heeled addict as a means to painlessly sleep through an opioid antagonist induction. The procedure is offered, however, without good evidence to support efficacy and despite numerous reports of serious adverse events, according Collins and colleagues (2005):
The eagerness with which both patients and the public have accepted claims of success highlights the desperation many patients and families feel about treating opioid dependence.
To evaluate the safety, tolerability and efficacy of anesthesia-assisted rapid opioid detoxification, the investigators compared the procedure to two other withdrawal programs that incorporate naltrexone induction. The study cohort consisted of 106 heroin users meeting DSM-IV criteria for opioid dependence for at least six months. Following each procedure, patients received clonidine to mitigate withdrawal symptoms as well as clonazepam(Drug information on clonazepam) (Klonopin) and ancillary medications as required. After hospital discharge, all patients were followed for 12 weeks, receiving naltrexone 50 mg daily and twice-weekly, manual-guided relapse-prevention psychotherapy. The researchers noted that an anticipated depot naltrexone formulation is likely to increase participation in, and success of, such programs, in contrast to the current poor rate of compliance with oral naltrexone.
Anesthesia was maintained for four to six hours, during which the opioid antagonist nalmefene (Revex) was infused intravenously 4 mg over 30 minutes, followed by naltrexone 50 mg via nasogastric tube. In the buprenorphine-assisted protocol, a single 8 mg sublingual "bridging" dose of this partial opioid agonist was administered to facilitate a more comfortable naltrexone induction two days later. Collins and colleagues explained that buprenorphine shortens the time until naltrexone can be administered and that it has a longer duration of action and less severe withdrawal than heroin. The initial naltrexone dose was 12.5 mg, increased to 25 mg on day 3 and then to 50 mg daily.
