ABSTRACT
The polymorphic cytochrome 2D6 [CYP2D6] causing ultrarapid metabolism due to presence of multiple copies of active CYP2D6 genes is common in middle east population. The CYP2D6 genotype of Egyptian population was examined using allele- specific polymerase chain reaction [PCR] amplification. Among thirty neuropathic pain patients studied, twenty patients [66.6%] were positive in the duplication assay. Alleles that cause diminished enzyme activity were frequently found like CYP2D6*17 [African gene] [23.3%,] and allele CYP2D6*4 [European gene] which showed a frequency of [16.6%] .None of the patients was homozygous for CYP2D6*4,. strongly suggesting that no poor metabolizer [PM] individuals in the studied population. This is in agreement with earlier phenotyping study among Egyptians. The patients studied showed a rapid and obvious response to oral tramadol [50 mg, tds.] .Results imply that gene deletion may not he the only modulatory factor responsible for the clinical outcome following tramadol therapy