The purpose of this prospective study was to determine the effect of CYP2D6 gene polymorphism on perioperative analgesia of oxycodone in elderly patients, and to assign the CYP2D6 phenotype according to the genotype, and to use inhibitors for pain control of phenotype conversion. The significance is to accurately guide the perioperative analgesia of oxycodone in elderly patients, and to more effectively avoid toxicity and adverse reactions.

CYP2D6 is a subfamily of P450, and its gene is highly polymorphic, which can affect the conversion of enzyme activity. CYP2D6 is involved in the metabolism of opioid drugs such as morphine, tramadol, codeine, oxycodone and so on. According to allele mutation, CYP2D6 individuals are predicted to have different phenotypes : weak metabolizer ( PM ), intermediate metabolizer ( IM ), normal metabolizer ( NM ) and ultra-fast metabolizer ( UM ).The data from this study support the potential benefits of CYP2D6-guided pain treatment, using inhibitors to reduce CYP2D6 metabolic activity, reduce the production of excessive metabolites, and avoid toxicity and adverse reactions. Oxycodone is a μ-opioid receptor agonist. A number of studies have found that significant genetic variations in CYP2D6 activity affect the conversion of oxycodone. Gene polymorphism significantly affects the metabolism and elimination of oxycodone by affecting the enzyme activity of CYP2D6, thus affecting its analgesic effect.

Inclusion Criteria:

( 1 ) Age ≥ 60 years old ; ( 2 ) ASA grade I ~ II ; ( 3 ) Receiving radical resection of lung cancer ; ( 4 ) BMI was 18.5 ~ 29.9 kg / m2 [ BMI = weight ( Kg ) / height ( m ) 2 ] ( 2013 US ' Adult Overweight and Obesity Management Guidelines ' ).

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Exclusion Criteria:

( 1 ) Patients with severe liver and kidney dysfunction ( severe liver dysfunction : ALT, AST, ALP, total bilirubin, etc. One of them > 2 times the upper limit of normal value. Severe renal dysfunction : creatinine > 2 times the upper limit of normal ) ; ( 2 ) Identify / suspect abuse or long-term use of narcotic sedative analgesics ; ( 3 ) Reoperation within 3 months ; ( 4 ) Patients with contraindications or allergies to test drugs and other narcotic drugs ; ( 5 ) CYP2D6 inhibitors or inducers were used within 30 days ; ( 6 ) Have a history of smoking, heavy drinking or drug use.

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During the trial period, patients who needed thoracoscopic lung surgery in Henan Provincial People 's Hospital were older than 60 years old.