Effective dose of intravenous oxycodone depending on sex and age for attenuation of intubation-related hemodynamic responses.

Background/aim: Preoperative intravenous oxycodone may help to prevent or attenuate intubation-related hemodynamic responses (IRHRs), but its pharmacokinetics differs according to age and sex. Therefore, we investigated the 95% effective dose (ED95) of intravenous oxycodone for attenuating all IRHRs, depending on the age and sex of the study population.

Materials And Methods: All patients were allocated to one of 6 groups: 1) 20–40 year old males, 2) 41–65yearold males, 3) 66–80 year old males, 4) 20–40 year old females, 5) 41–65yearold females, and 6) 66–80 year old females (groups YM, OM, EM, YF, OF, and EF, respectively). Using Dixon’s up-and-down method, the first patient in each group was slowly injected with intravenous oxycodone (0.1 mg kg–1) 20 min before intubation. The subsequent patient received the next oxycodone dose, which was decreased or increased by 0.01 mg kg–1, depending on the “success” or “failure” of attenuation of all IRHRs to within 20% of the baseline values at 1 min after intubation in the previous patient. After obtaining 8 crossover points, predictive ED95 was estimated with probit regression analysis.

Results: ED95 varied greatly according to age and sex. ED95was 0.133 mg kg–1, 0.181 mg kg–1, 0.332 mg kg–1, 0.183 mg kg–1, 0.108 mg kg–1, and 0.147 mg kg–1in groups YM, OM, EM, YF, OF, and EF, respectively.

Conclusion: ED95 is higher in males with increasing age but is ambiguous for females. ED95 is higher in males than in females over 40 years of age but is higher in females than in males under 41 years of age. However, after considering the age and sex of the study population, these results can be used as reference doses for further studies to verify the clinical effects of oxycodone for attenuating all IRHRs.