title: Sex and opioid maintenance dose influence response to naloxone in opioid-dependent humans: a retrospective analysis.
abstract: Pooled self-report and physiological data from 32 male and 15 female methadone or levo-alpha-acetyl methadol (LAAM) maintained volunteers were retrospectively analyzed for individual differences in response to naloxone (0.15 mg/70 kg, IM) and placebo at 20 and 40 min post-injection. Males and females were each divided by the median splitmethadone maintenance dose (MMD, in mg/kg body weight) into high and low MMD groups and MMD was used as a factor in the analyses, along with sex, drug, and time post-drug. Females in the low but not high, MMD group showed naloxone-induced increases in ratings on the Antagonist and Mixed-Action sub-scales of the Adjective Rating Scale, and the Lysergic acid diethyl amine (LSD) sub-scale of the Addiction Research Center Inventory at 20 min post-injection. Males in the high MMD group showed significant naloxone-induced increases in scores of these measures at both post-injection time-points. In addition, low MMD subjects showed more short-lived naloxone-induced increases on Visual Analogue Scale (VAS) Bad and Any drug effects ratings than high MMD subjects. These results suggest that those on a lower MMD, especially women, experience a more intense, but short-lived, response to naloxone, whereas those on a higher MMD experience a more modest, but longer-lasting effect.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
authors.forename: Mohit P
authors.initials: MP
authors.lastname: Chopra
authors.forename: Zachary
authors.initials: Z
authors.lastname: Feldman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mancino
authors.forename: Alison
authors.initials: A
authors.lastname: Oliveto
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D008692:Methadyl Acetate / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D009270:Naloxone / Q000009:adverse effects / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000009:adverse effects / Q000494:pharmacology*; D009294:Narcotics / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D009293:Opioid-Related Disorders / Q000523:psychology* / Q000534:rehabilitation; D012189:Retrospective Studies; D012727:Sex Characteristics; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology / Q000517:prevention & control / Q000523:psychology
chemical_list: D009292:Narcotic Antagonists; D009294:Narcotics; D009270:Naloxone; D008692:Methadyl Acetate; D008691:Methadone