CYP2D6, a liver enzyme, plays a key role in metabolizing a range of drugs, including antidepressants, β-blockers, tamoxifen, and opioids such as tramadol and codeine, with notable inter-individual differences in drug response due to its high genetic polymorphism. This study investigated CYP2D6 polymorphisms in Kurdish women receiving tramadol after cesarean delivery. Forty participants from Maternity Teaching Hospital provided DNA samples, which were genotyped for CYP2D6 using polymerase chain reaction. Based on their CYP2D6 activity scores, participants were categorized into distinct phenotype groups. Analgesic efficacy and adverse effects were evaluated at 1 and 6 hours after tramadol administration. The CYP2D641 allele was the most prevalent (26.25%), with thirteen genotypes identified, and no ultrarapid metabolizers were detected among the participants. Poor metabolizers reported the highest mean visual analog scale scores at 1 hour (5.33 ± 1.70) and at 6 hours (5.53 ± 1.05). However, the occurrence of side effects did not significantly differ between phenotype groups. The findings indicate that CYP2D6*41 is the most common allele in this population, with poor metabolizers experiencing greater pain, highlighting that CYP2D6 polymorphism influences tramadol analgesic efficacy without affecting the incidence of side effects.
