. Author manuscript; available in PMC: 2023 Nov 1.

Published in final edited form as: Clin Pharmacol Ther. 2022 Aug 20;112(5):1120–1129. doi: 10.1002/cpt.2717

Table 1.

Key parameters for methadone and buprenorphine in pharmacokinetic DDI screening

Drug name	Fraction of hepatic metabolism through cytochrome P450 pathway (f_m)						Fraction excreted unchanged in urine (f_e)
Drug name	CYP2B6	CYP3A4	CYP2C19	CYP2C8	CYP2D6	Others	Fraction excreted unchanged in urine (f_e)
Methadone^a	0.744	0.035	0.017	0.000	0.091	0.11	0.24
Buprenorphine^b	0.000	0.885	0.000	0.051	0.000	0.064	0.01

DDI, drug–drug interaction.

Estimates of f_m obtained from regression analysis of data reported in reference 30. Estimates of f_e obtained from reference 27.

Estimates of f_m obtained from reference 10. Estimates of f_e obtained from reference ²⁷.