The Impact of Pharmacogenetics on Adverse Drug Reactions to Predict the Efficacy of Tramadol Monotherapy for the Treatment of Post Herpetic Neuralgia Patients

Objective: To evaluate the potential role of tramadol treatment with respect to CYP2D6 polymorphism in reducing the incidence of adverse drug reactions. Methods: The study comprised 246 patients of PHN receiving tramadol treatment. Adverse drug events during the time of the study were recorded by the physician. All samples were analyzed for CYP2D6 (*2, *4 and *10) polymorphism using PCR-RFLP method. Results: The CYP2D6 polymorphism did not find significantly among onset at age, genders and weight in non-responders and responders. The CYP2D6*4 polymorphism was significantly associated with somnolence (p=0.009), dizziness (p=0.007), local site reactions (p=0.015), headache (p=0. 039), and nausea and vomiting (p=0. 017). The dizziness (p=0. 029) and headache (p=0. 004) were found associated with CYP2D6*2 both the groups. No associations were observed between adverse events compared with CYP2D6*2 and CYP2D6*10 polymorphisms (p>0.05). Conclusion: CYP2D6*4 polymorphism may be as important drug toxicity marker predictors of experiencing adverse drug reactions as PHN patients undergoing tramadol treatment.