Narcotic antagonists in drug dependence: pilot study showing enhancement of compliance with SYN-10, amino-acid precursors and enkephalinase inhibition therapy.
We decided to test the hypothesis that possibly by combining a narcotic antagonist and amino-acid therapy consisting of an enkephalinase inhibitor (D-phenylalanine) and neurotransmitter precursors (L-amino- acids) to promote neuronal dopamine release might enhance compliance in methadone patients rapidly detoxified with the narcotic antagonist Trexan (Dupont, Delaware). In this regard, Thanos et al. [J. Neurochem. 78 (2001) 1094] and associates found increases in the dopamine D2 receptors (DRD2) via adenoviral vector delivery of the DRD2 gene into the nucleus accumbens, significantly reduced both ethanol preference (43%) and alcohol intake (64%) of ethanol preferring rats, which recovered as the DRD2, returned to baseline levels. This DRD2 overexpression similarly produced significant reductions in ethanol non-preferring rats, in both alcohol preference (16%) and alcohol intake (75%). This work further suggests that high levels of DRD2 may be protective against alcohol abuse [JAMA 263 (1990) 2055; Arch, Gen. Psychiatr. 48 (1991) 648]. The DRD2 A1 allele has also been shown to associate with heroin addicts in a number of studies. In addition, other dopaminergic receptor gene polymorphisms have also associated with opioid dependence. For example, Kotler et al. [Mol. Phychiatr. 3 (1997) 251] showed that the 7 repeat allele of the DRD4 receptor is significantly overpresented in the opioid-dependent cohort and confers a relative risk of 2.46. This has been confirmed by Li et al. [Mol. Psychiatry 2 (1997) 413] for both the 5 and 7 repeat alleles in Han Chinese case control sample of heroin addicts. Similarly Duaux et al. [Mol. Psychiatry 3 (1998) 333] in French Heroin addicts, found a significant association with homozygotes alleles of the DRD3-Bal 1. A study from NIAAA, provided evidence which strongly suggests that DRD2 is a susceptibility gene for substance abusers across multiple populations (2003). Moreover, there are a number of studies utilizing amino-acid and enkephalinase inhibition therapy showing reduction of alcohol, opiate, cocaine and sugar craving behavior in human trials (see Table 1). Over the last decade, a new rapid method to detoxify either methadone or heroin addicts utilizing Trexan sparked interest in many treatment centers throughout the United States, Canada, as well as many countries on a worldwide basis. In using the combination of Trexan and amino-acids, results were dramatic in terms of significantly enhancing compliance to continue taking Trexan. The average number of days of compliance calculated on 1000 patients, without amino-acid therapy, using this rapid detoxification method is only 37 days. In contrast, the 12 subjects tested, receiving both the Trexan and amino-acid therapy was relapse-free or reported taking the combination for an average of 262 days (p < 0.0001F). Thus coupling amino-acid therapy and enkephalinase inhibition while blocking the delta-receptors with a pure narcotic antagonist may be quite promising as a novel method to induce rapid detox in chronic methadone patients. This may also have important ramifications in the treatment of both opiate and alcohol-dependent individuals, especially as a relapse prevention tool. It may also be interesting too further test this hypothesis with the sublingual combination of the partial opiate mu receptor agonist buprenorphrine.
Chen
Thomas J H
TJ
Chang Jung Christian University, Tainan, Taiwan, ROC.
Blum
Kenneth
K
Payte
James T
JT
Schoolfield
John
J
Hopper
David
D
Stanford
Mathew
M
Braverman
Eric R
ER
D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000008:administration & dosage*; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009271:Naltrexone / Q000008:administration & dosage*; D009292:Narcotic Antagonists / Q000008:administration & dosage*; D015260:Neprilysin / Q000037:antagonists & inhibitors*; D009293:Opioid-Related Disorders / Q000453:epidemiology* / Q000517:prevention & control*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D010649:Phenylalanine / Q000008:administration & dosage; D010865:Pilot Projects; D055502:Secondary Prevention; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome
D000596:Amino Acids; D004338:Drug Combinations; D009292:Narcotic Antagonists; D010649:Phenylalanine; D009271:Naltrexone; D015260:Neprilysin