There was no significant difference in duration of epidural fentanyl analgesia for the three SNVs (161±68 and 143±51 min for wild type and allele carriers of the 118A>G SNV respectively [P=0.08]).
Genetic variants in OPRM1, particularly the non-synonymous polymorphism A118G, have been repeatedly associated with the efficacy of treatments for pain and various types of dependence.
Variation at a single nucleotide polymorphism in the μ-opioid receptor gene (OPRM1), A118G (Asn40Asp), may moderate naltrexone (NTX) effects in alcohol dependence.
The results indicate that among the genetic SNPs we studied which include those affecting analgesic drug metabolism, transport of analgesic agents across the blood-brain barrier, and their activity at target receptors and ion channels and in the modulation of neurotransmitter pathways, the A118G allele variant of OPRM1 has the most potent influence on pain management of postoperative patients.
Regarding the A118G SNP in exon 1, in a cold pressor-induced pain test before surgery, less analgesic effects of fentanyl were shown in subjects carrying the minor G allele of the A118G SNP (median of difference between pain perception latencies before and after fentanyl injection [PPLpost-PPLpre]: 12s) compared with subjects not carrying this allele (PPLpost-PPLpre: 15s, p=0.046).
This paper will review converging lines of evidence on the effect of the Asn40Asp SNP on alcoholism phenotypes, including: (i) genetic association studies; (ii) behavioral studies of alcoholism; (iii) neuroimaging studies; (iv) pharmacogenetic studies and clinical trials; and (v) preclinical animal studies.
In the present study, we compared the frequencies of the polymorphism OPRM1 A118G between patients with alcohol dependence and healthy control subjects living in a Japanese provincial prefecture.
Polymorphisms of OPRM1 A118G and ABCB1 C3435T have been suggested to contribute to inter-individual variability regarding pain sensitivity, opioid usage, tolerance and dependence and incidence of adverse effects in patients with chronic pain.
Patients homozygous for the variant G allele of the 118 A > G polymorphism (n = 4) needed more morphine to achieve pain control, compared to heterozygous (n = 17) and homozygous wild-type (n = 78) individuals.
In a subpopulation, identifying OPRM1 A118G polymorphism may provide valuable information regarding the individual analgesic doses that are required to achieve satisfactory pain control.
In comparison, two pain-related gene SNPs (OPRM1 [rs1799971] and COMT [rs4818]) interacted with psychological factors to predict four shoulder impairment phenotypes (abduction: 5-day average loss; strength loss: 5-day average, peak, and relative loss).