A Multicenter Retrospective Observational Study Analyzing the Effect of Polypharmacy on Oxycodone Tolerability

Area of Science:

• Oncology
• Pharmacology
• Clinical Pharmacy

Background:

• Polypharmacy presents challenges in cancer care.
• Understanding drug-drug interactions is vital for patient safety and treatment efficacy.

Purpose of the Study:

• To investigate the impact of concomitant polypharmacy, specifically drugs inhibiting CYP3A4 and/or CYP2D6, on oxycodone tolerability in cancer patients.
• To identify risk factors for oxycodone discontinuation, dose reduction, and oxycodone-induced nausea and vomiting (OINV).

Main Methods:

• A multicenter retrospective study involving 20 hospitals.
• Data collected during the initial 2 weeks of oxycodone administration.
• Comparison of OINV incidence and oxycodone discontinuation/dose reduction rates between patients with and without concomitant CYP3A4 or CYP2D6 inhibitors.

Main Results:

• The incidence of OINV was significantly higher in patients taking two concomitant CYP3A4 inhibitors (29.8%) compared to those without (15.5%; p=0.049).
• Multivariate analysis identified more than two concomitant CYP3A4 inhibitors as an independent risk factor for OINV.
• A trend towards higher oxycodone discontinuation or dose reduction was observed with ≥3 concomitant CYP2D6 inhibitors (18.2% vs 8.2%; p=0.09).

Conclusions:

• Concomitant polypharmacy involving CYP3A4 inhibitors is associated with an increased risk of OINV in cancer patients.
• Optimization of concomitant medications used with oxycodone is recommended to improve tolerability and reduce side effects.