title: The AC/AG Diplotype for the 118A>G and IVS2 + 691G>C Polymorphisms of OPRM1 Gene is Associated with Sleep Quality Among Opioid-Dependent Patients on Methadone Maintenance Therapy.
abstract: BACKGROUND
  Methadone is a full agonist of the opioid receptor mu 1 which is encoded by the OPRM1 gene. Sleep disorders were frequently reported by opioid-dependent patients during methadone maintenance therapy (MMT). It is possible, therefore, that genetic polymorphisms in OPRM1 influence sleep quality among patients on MMT. This study investigated the association of OPRM1 polymorphisms with sleep quality among opioid-dependent patients on MMT.
  
  
  METHODS
  The sleep quality of 165 male opioid-dependent patients receiving MMT was evaluated using the Pittsburgh Sleep Quality Index (PSQI). DNA was extracted from whole blood and subjected to polymerase chain reaction (PCR) genotyping.
  
  
  RESULTS
  Patients with IVS2 + 691 CC genotype had higher PSQI scores [mean (SD) = 5.73 (2.89)] compared to those without the IVS2 + 691 CC genotype (IVS2 + 691 GG/GC genotype) [4.92 (2.31)], but the difference did not reach statistical significance (p = 0.081). Patients with combined 118 AA genotype and IVS2 + 691 GC genotype (AC/AG diplotype) had significantly lower PSQI scores [mean (SD) = 4.25 (2.27)] compared to those without the diplotype [5.68 (2.77)] (p = 0.018).
  
  
  CONCLUSIONS
  Our study indicates that the AC/AG diplotype for the 118A>G and IVS2 + 691G>C polymorphisms of OPRM1 gene is associated with better sleep quality among males with opioid dependence on MMT.
authors.affiliation: Department of Pharmacy, Hospital Universiti Sains Malaysia, Kota Bharu, Kelantan, Malaysia. zzalina@usm.my.|Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia. zzalina@usm.my.
authors.forename: Zalina
authors.initials: Z
authors.lastname: Zahari
authors.affiliation: Department of Emergency Medicine, School of Medical Sciences, Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.
authors.forename: Chee Siong
authors.initials: CS
authors.lastname: Lee
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.|Department of Pharmacology and Toxicology, College of Pharmacy, Hawler Medical University, Erbil, Iraq.
authors.forename: Muslih Abdulkarim
authors.initials: MA
authors.lastname: Ibrahim
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.
authors.forename: Nurfadhlina
authors.initials: N
authors.lastname: Musa
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.|Department of Psychiatry, School of Medical Sciences, Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.
authors.forename: Mohd Azhar
authors.initials: MA
authors.lastname: Mohd Yasin
authors.affiliation: School of Medical Sciences, Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.
authors.forename: Yeong Yeh
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.
authors.forename: Soo Choon
authors.initials: SC
authors.lastname: Tan
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.|Faculty of Medicine and Health Sciences, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia.
authors.forename: Nasir
authors.initials: N
authors.lastname: Mohamad
authors.affiliation: Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Kota Bharu, Kelantan, Malaysia.|Centre of Excellence for Research in AIDS (CERiA), University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Rusli
authors.initials: R
authors.lastname: Ismail
keywords: AC/AG diplotype; Male patients; Methadone; Methadone maintenance therapy; OPRM1; Opioid dependence; Opioid receptor; Opioid receptor, mu 1 gene; Pittsburgh Sleep Quality Index; Sleep quality