Inhibition of cytochrome P450 2D6 metabolism of hydrocodone to hydromorphone does not importantly affect abuse liability

ABSTRACT Enzymatic conversion of hydrocodone to hydromorphone is catalyzed by cytochrome P450 2D6, which is inactive in about 7% of Caucasians [poor metabolizers (PMs)] and can be inhibited by quinidine pretreatment in the remainder [extensive metabolizers (EMs)]. If hydromorphone, having a substantially higher -receptor affinity than hydrocodone, contributes importantly to the physiological and subjective effects of oral hydrocodone, then PMs should be less responsive to the same doses, and quinidine pretreatment should cause EMs to temporarily respond as PMs. Seventeen EMs and 8 PMs who previously responded positively to hydromorphone s.c. received placebo and hydrocodone (10 mg, 15 mg and 22.5 mg p.o.) and were retested with their favorite dose after placebo or quinidine (100 mg) pretreatment; physiological and subjective measures were collected at base line and four times after drug administration, and urine was collected for 8 hr. EMs and PMs were equally responsive to oral hydrocodone, and quinidine had no consistent effect on their responses, even though quinidine abolished the pre-existing metabolic differences in hydromorphone production, as measured in urine. These data suggest only a small role of hydromorphone in eliciting abuserelated responses to oral hydrocodone. The genetic polymorphism of the drug-metabolizing enzyme CYP2D6 results in phenotypic differences in the pharmacokinetics of many drugs One drug for which there is evidence of phenotypic differences in response is codeine, which is O-demethylated by CYP2D6 to form morphine Hydrocodone differs structurally from codeine in that the C6-position is occupied by a keto-group, and thus the drug does not undergo the extensive conjugation (Ͼ60%) that codeine undergoe

Characteristics of Long Term Alprazolam Users in the Community

The widespread use of benzodiazepines remains a source of concern to the medical profession and the general public, especially as newer compounds come on the market. Our goal was to characterize long-term alprazolam users in the community and to determine whether such use represented abuse or behavioural dependence. We conducted three community surveys to learn about the natural history of long-term alprazolam use. Current long-term alprazolam users (those using the drug for 3 months or longer) were recruited on three separate occasions 1 year apart by identical newspaper advertisements in the metropolitan Toronto area. All respondents were mailed a questionnaire with a stamped, addressed return envelope. Our data from 312 respondents show that: (1) the majority of patients have a substantial history of prior medication use for symptom control (65%), (2) dose escalation is not a characteristic of long-term use, (3) patients change their initial pattern of regular use to one of symptom control only when required, (4) most physicians do not discuss discontinuation of the drug with their patients, (5) patients frequently try to stop their drug use (with a median of 2 attempts) and often report symptoms upon discontinuation, and (6) patients perceive a need for medication use and indicate that alprazolam is effective (75%). We conclude that some patients persistently use alprazolam but that this use does not represent abuse or behavioral dependence

Large-Scale Exome Sequencing Study Implicates Both Developmental and Functional Changes in the Neurobiology of Autism

International audienceWe present the largest exome sequencing study of autism spectrum disorder (ASD) to date (n = 35,584 total samples, 11,986 with ASD). Using an enhanced analytical framework to integrate de novo and case-control rare variation, we identify 102 risk genes at a false discovery rate of 0.1 or less. Of these genes, 49 show higher frequencies of disruptive de novo variants in individuals ascertained to have severe neurodevelopmental delay, whereas 53 show higher frequencies in individuals ascertained to have ASD; comparing ASD cases with mutations in these groups reveals phenotypic differences. Expressed early in brain development, most risk genes have roles in regulation of gene expression or neuronal communication (i.e., mutations effect neurodevelopmental and neurophysiological changes), and 13 fall within loci recurrently hit by copy number variants. In cells from the human cortex, expression of risk genes is enriched in excitatory and inhibitory neuronal lineages, consistent with multiple paths to an excitatory-inhibitory imbalance underlying ASD

Large-scale exome sequencing study implicates both developmental and functional changes in the neurobiology of autism

Summary We present the largest exome sequencing study of autism spectrum disorder (ASD) to date (n=35,584 total samples, 11,986 with ASD). Using an enhanced Bayesian framework to integrate de novo and case-control rare variation, we identify 102 risk genes at a false discovery rate ≤ 0.1. Of these genes, 49 show higher frequencies of disruptive de novo variants in individuals ascertained for severe neurodevelopmental delay, while 53 show higher frequencies in individuals ascertained for ASD; comparing ASD cases with mutations in these groups reveals phenotypic differences. Expressed early in brain development, most of the risk genes have roles in regulation of gene expression or neuronal communication (i.e., mutations effect neurodevelopmental and neurophysiological changes), and 13 fall within loci recurrently hit by copy number variants. In human cortex single-cell gene expression data, expression of risk genes is enriched in both excitatory and inhibitory neuronal lineages, consistent with multiple paths to an excitatory/inhibitory imbalance underlying ASD

Large-scale exome sequencing study implicates both developmental and functional changes in the neurobiology of autism

We present the largest exome sequencing study of autism spectrum disorder (ASD) to date (n = 35,584 total samples, 11,986 with ASD). Using an enhanced analytical framework to integrate de novo and case-control rare variation, we identify 102 risk genes at a false discovery rate of 0.1 or less. Of these genes, 49 show higher frequencies of disruptive de novo variants in individuals ascertained to have severe neuro-developmental delay, whereas 53 show higher frequencies in individuals ascertained to have ASD; comparing ASD cases with mutations in these groups reveals phenotypic differences. Expressed early in brain development, most risk genes have roles in regulation of gene expression or neuronal communication (i.e., mutations effect neurodevelopmental and neurophysiological changes), and 13 fall within loci recurrently hit by copy number variants. In cells from the human cortex, expression of risk genes is enriched in excitatory and inhibitory neuronal lineages, consistent with multiple paths to an excitatory-inhibitory imbalance underlying ASD