RESUMEN
There is a complex relationship between drug dependence and stress, with alcohol and other drugs of abuse both relieving stress and potentially inducing physiological stress responses in the user. Opioid drugs have been shown to modulate hypothalamic-pituitary-adrenal (HPA) activity in animal models and individual response to this modulation may play a role in continuation of drug use. Healthy young Caucasian adults were administered a single dose of immediate release oxycodone (20mg, n=30) or assigned to a control group (n=19) that was not administered the drug. At 0, 1, 2, 4 and 6h post-administration, blood and saliva samples were collected along with assessment of pupil diameter. The HPA response was determined by measurement of salivary cortisol through a commercially available enzyme-linked immunosorbent assay (ELISA). The results were compared to genotype at the -511 and -31 positions in the interleukin1B (IL1B) gene. No difference in cortisol production was initially observed between the two groups, however, when participants were separated based on their genotype for two single nucleotide polymorphisms in the promoter of the IL1B gene, which have been shown to occur at a higher frequency in opioid-dependent populations, individuals carrying the -511T and -31 C alleles (-511 C/T, -31 C/T or -511 T/T, -31 C/C) had a significantly (p<0.05) higher cortisol levels compared to individuals homozygous for the -511 C and -31T alleles. These results suggest that individuals carrying the -511T and -31 C alleles experience HPA activation in response to opioid administration and therefore may be less likely to undertake subsequent self-administration.
Asunto(s)
Analgésicos Opioides/farmacología , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Interleucina-1beta/genética , Oxicodona/farmacología , Sistema Hipófiso-Suprarrenal/efectos de los fármacos , Alelos , Femenino , Variación Genética , Genotipo , Humanos , Hidrocortisona/metabolismo , Masculino , Trastornos Relacionados con Opioides/genética , Polimorfismo de Nucleótido Simple/genética , Pupila/efectos de los fármacos , Adulto JovenRESUMEN
We assessed the suitability of six applied tests of cognitive functioning to provide a single marker for dose-related alcohol intoxication. Numerous studies have demonstrated that alcohol has a deleterious effect on specific areas of cognitive processing but few have compared the effects of alcohol across a wide range of different cognitive processes. Adult participants (Nâ=â56, 32 males, 24 females aged 18-45 years) were randomized to control or alcohol treatments within a mixed design experiment involving multiple-dosages at approximately one hour intervals (attained mean blood alcohol concentrations (BACs) of 0.00, 0.048, 0.082 and 0.10%), employing a battery of six psychometric tests; the Useful Field of View test (UFOV; processing speed together with directed attention); the Self-Ordered Pointing Task (SOPT; working memory); Inspection Time (IT; speed of processing independent from motor responding); the Traveling Salesperson Problem (TSP; strategic optimization); the Sustained Attention to Response Task (SART; vigilance, response inhibition and psychomotor function); and the Trail-Making Test (TMT; cognitive flexibility and psychomotor function). Results demonstrated that impairment is not uniform across different domains of cognitive processing and that both the size of the alcohol effect and the magnitude of effect change across different dose levels are quantitatively different for different cognitive processes. Only IT met the criteria for a marker for wide-spread application: reliable dose-related decline in a basic process as a function of rising BAC level and easy to use non-invasive task properties.
Asunto(s)
Cognición/efectos de los fármacos , Etanol/farmacología , Adolescente , Adulto , Relación Dosis-Respuesta a Droga , Etanol/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicometría , Adulto JovenRESUMEN
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Management of pain in opioid dependent individuals is problematic due to numerous issues including cross-tolerance to opioids. Hence there is a need to find alternative analgesics to classical opioids and tramadol is potentially one such alternative. Methadone inhibits CYP2D6 in vivo and in vitro. We aimed to investigate the effect of methadone on the pathways of tramadol metabolism: O-demethylation (CYP2D6) to the opioid-active metabolite M1 and N-demethylation (CYP3A4) to M2 in subjects maintained on methadone or buprenorphine as a control. WHAT THIS STUDY ADDS: Compared with subjects on buprenorphine, methadone reduced the clearance of tramadol to active O-desmethyl-tramadol (M1) but had no effect on N-desmethyltramadol (M2) formation. Similar to other analgesics whose active metabolites are formed by CYP2D6 such as codeine, reduced formation of O-desmethyltramadol (M1) is likely to result in reduced analgesia for subjects maintained on methadone. Hence alternative analgesics whose metabolism is independent of CYP2D6 should be utilized in this patient population. AIMS: To compare the O- (CYP2D6 mediated) and N- (CYP3A4 mediated) demethylation metabolism of tramadol between methadone and buprenorphine maintained CYP2D6 extensive metabolizer subjects. METHODS Nine methadone and seven buprenorphine maintained subjects received a single 100 mg dose of tramadol hydrochloride. Blood was collected at 4 h and assayed for tramadol, methadone, buprenorphine and norbuprenorphine (where appropriate) and all urine over 4 h was assayed for tramadol and its M1 and M2 metabolites. RESULTS: The urinary metabolic ratio [median (range)] for O-demethylation (M1) was significantly lower (P= 0.0002, probability score 1.0) in the subjects taking methadone [0.071 (0.012-0.103)] compared with those taking buprenorphine [0.192 (0.108-0.392)], but there was no significant difference (P= 0.21, probability score 0.69) in N-demethylation (M2). The percentage of dose [median (range)] recovered as M1 was significantly lower in subjects taking methadone compared with buprenorphine (0.069 (0.044-0.093) and 0.126 (0.069-0.187), respectively, P= 0.04, probability score 0.19), M2 was significantly higher in subjects taking methadone compared with buprenorphine (0.048 (0.033-0.085) and 0.033 (0.014-0.049), respectively, P= 0.04, probability score 0.81). Tramadol was similar (0.901 (0.635-1.30) and 0.685 (0.347-1.04), respectively, P= 0.35, probability score 0.65). CONCLUSIONS: Methadone inhibited the CYP2D6-mediated metabolism of tramadol to M1. Hence, as the degree of opioid analgesia is largely dependent on M1 formation, methadone maintenance patients may not receive adequate analgesia from oral tramadol.
Asunto(s)
Analgésicos Opioides/farmacocinética , Buprenorfina/farmacología , Metadona/farmacología , Tramadol/farmacocinética , Administración Oral , Adolescente , Adulto , Analgésicos Opioides/farmacología , Citocromo P-450 CYP2D6/metabolismo , Inhibidores del Citocromo P-450 CYP2D6 , Citocromo P-450 CYP3A/metabolismo , Interacciones Farmacológicas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tratamiento de Sustitución de Opiáceos , Tramadol/análogos & derivados , Adulto JovenRESUMEN
Given the evidence from retrospective studies indicating that alcohol-dependent patients with homozygous or heterozygous A118G variant of the µ-opioid receptor, OPRM1, gene have significantly better outcomes when treated with naltrexone; this study examined this prospectively in 100 alcohol-dependent participants prescribed naltrexone for 12 weeks and offered six sessions of cognitive-behavioral therapy or intervention. Comparisons were made among OPRM1 genotypic groups on several outcome measures. Naltrexone treatment produced significant decreases in self-reported and objective indicators of alcohol use and craving from baseline (P<0.0001 and 0.017, respectively), particularly during the first 2 months of treatment, with 68% completing the study. However, there was no evidence of a significant association between OPRM1 A118G genotype and treatment success on any of the outcome measures. Therefore, while naltrexone was an effective treatment for alcohol dependence, the OPRM1 A118G genotype was not a predictor of success.
Asunto(s)
Alcoholismo/tratamiento farmacológico , Alcoholismo/genética , Naltrexona/uso terapéutico , Antagonistas de Narcóticos/uso terapéutico , Receptores Opioides mu/genética , Adulto , Australia , Terapia Cognitivo-Conductual , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Población BlancaRESUMEN
An open-label study reported that ingestion of a fish oil concentrate decreased the incidence of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery. However, a general cardiac surgery population involves valve and CABG surgeries. We undertook a double-blinded randomized controlled trial to examine the effectiveness of fish oil supplementation on the incidence of postsurgical AF after CABG and valve procedures. The primary end point was incidence of AF in the first 6 days after surgery. Two hundred patients were randomized to receive fish oil (providing 4.6 g/day of long-chain ω-3 fatty acids) or a control oil starting 3 weeks before surgery; 194 subjects completed the study, with 47 of 97 subjects in the control group and 36 of 97 subjects in the fish oil group developing AF (odds ratio 0.63, 95% confidence interval [CI] 0.35 to 1.11). There was a nonstatistically significant delay in time to onset of AF in the fish oil group (hazard ratio 0.66, 95% CI 0.43 to 1.01). There was a significant decrease in mean length of stay in the intensive care unit in the fish oil group (ratio of means 0.71, 95% CI 0.56 to 0.90). In conclusion, in a mixed cardiac surgery population, supplementation with dietary fish oil did not result in a significant decrease in the incidence of postsurgical AF. However, there was a significant decrease in time spent in the intensive care unit.
Asunto(s)
Fibrilación Atrial/prevención & control , Procedimientos Quirúrgicos Cardíacos , Aceites de Pescado/uso terapéutico , Complicaciones Posoperatorias/prevención & control , Anciano , Suplementos Dietéticos , Método Doble Ciego , Femenino , Humanos , Incidencia , Unidades de Cuidados Intensivos/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Placebos , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Resultado del TratamientoRESUMEN
There has been recent concern about the association between high dose methadone and prolongation of QTc in the electrocardiogram. QTc is the time from the beginning of the QRS complex to the end of the T have as measured on an electrocardiogram and corrected for heart rate. To date, no association has been made between methadone and buprenorphine in commonly used doses and prolonged QTc. Electrocardiograms were performed on groups of methadone (n = 35, mean daily dose +/- standard deviation, 69 +/- 29 mg) and buprenorphine (n = 19, mean daily dose 11 +/- 5 mg) subjects and a group of non-opioid dependent controls (n = 17). Mean QTc did not differ (p = 0.45) between methadone, buprenorphine, or controls. Methadone subjects were significantly (odds ratio of 7.8) more likely to have U waves than buprenorphine and controls combined. Methadone subjects with U waves were maintained on higher (p = 0.004) doses (89 +/- 29 mg/day) than methadone subjects without U waves (60 +/- 24 mg/day). Methadone subjects taking 60 mg and above had higher (p = 0.02) QTc (405 +/- 29 milliseconds) than methadone subjects taking less than 60 mg per day (381 +/- 27 milliseconds). Although an association is thought to exist between high methadone doses and elongated QTc, methadone and buprenorphine, at commonly used daily doses, remain safe agents for opioid substitution therapy.