Table 4.

Potential for DDIs associated with disruption of key cytochrome P450 enzymes

Opioid	Analgesic effects of DDIs
	Induction of CYP3A4	Inhibition of CYP3A4	Inhibition of CYP2D6
Morphinea	No likely clinical consequences	No likely clinical consequences	N/A
Hydrocodone	Potential increase in opioid effects; patient monitoring recommended	Potential decrease in opioid effects; patient monitoring recommended	N/A
Oxycodone	Decrease in opioid effects; avoid combination when possible	Increase in opioid effects (black box warning); avoid combination	Potential decrease in opioid effects
Oxymorphonea	N/A	N/A	N/A
Buprenorphine	Decrease in opioid effects	Increase in opioid effects	N/A
Levorphanola	N/A	N/A	N/A
Fentanyl	Decrease in opioid effects; avoid combination when possible	Increase in opioid effects (black box warning); avoid combination	N/A
Methadone	Decrease in opioid effects; avoid combination	Increase in opioid effects; avoid combination when possible	Increase in opioid effects; avoid combination

^aNotes: Drugs metabolized primarily by UGT2B7 (Phase II) and not likely to be associated with significant DDIs caused by alterations to CYP3A4 and CYP2D6. For more information on Buprenorphine see McCance-Katz et al.¹⁴⁶ Copyright © 2011. Adapted from The American Journal of Managed Care. Overholser BR, Foster DR. Opioid pharmacokinetic drug-drug interactions. Am J Manag Care. 2011;17(suppl 11):S276–S287.¹⁴⁷

Abbreviations: CYP, cytochrome P450; DDIs, drug–drug interactions; N/A, not applicable.