Nicotine effect on the efficacy of hydrocodone and oxycodone in chronic pain patients

Hydrocodone and oxycodone are frequently prescribed for the control of moderate to severe pain. Smoking cigarettes however, has been reported to decrease the efficacy of hydrocodone in chronic pain patients. This study compared the efficacy of hydrocodone and oxycodone in smokers and nonsmokers. Following IRB approval signed informed consent , smokers and nonsmokers with chronic low back pain were assigned randomly to one of four groups, (Group I, hydrocodone-nonsmoker, Group II, hydrocodone-smoker, group III, oxycodone-non-smoker, Group IV, oxycodone-non-smoker) each consisting of thirty patients to receive equivalent doses of hydrocodone or oxycodone daily for 30 days for pain relief. Each patient was prescribed hydrocodone 7.5 mg with acetaminophen 325 mg in Groups I and II every 6 hours while patients in Groups III and IV received oxycodone 5mg with acetaminophen 325 mg, every 6 hours as needed. Patient VAS pain scores (0-10) were recorded daily. Urine continine, hydrocodone/hydromorphone and oxycodone/oxymorphone levels were done at the beginning and end of this study and CYP450 2D6 and 3A4/3A5 genetic tests were done at the beginning. Statistical analysis was done using Student’s t test and the Mann-Whitney test where indicated with p≤ 0.05 considered significant. There were no demographic differences between the groups. The mass of hydrocodone consumed and the pain scores within the hydrocodone groups were higher in Group II, while the oxycodone groups did not statistically differ (p ≤ 0.05) at the end of the 30 day study. Smokers prescribed hydrocodone had significantly (p ≤ 0.05) less pain relief than nonsmokers while there were no significant difference within the oxycodone groups. It is concluded that hydrocodone efficacy within groups is less in cigarette smokers while oxycodone efficacy within groups does not appear to be significantly affected by cigarettes in the population studied. The reason for this finding is unknown.