Deinduction of P-glycoprotein resulting in delayed viral response during hepatitis C treatment.

WHAT IS KNOWN AND OBJECTIVE: Drug-drug interactions can involve inhibition or induction of cell membrane transporters. Deinduction occurs after an inducing agent is stopped. CASE SUMMARY: This case describes suspected P-glycoprotein (P-gp) deinduction by carbamazepine resulting in a slow viral response during treatment of chronic hepatitis C virus (HCV) infection. Evidence of deinduction occurred beyond clearance of carbamazepine and resulted in extension of HCV treatment. WHAT IS NEW: The understanding of the role P-gp transport plays in drug elimination is relatively new and evidence of P-gp deinduction is variable. CONCLUSION: Clinicians should consider deinduction when starting and stopping medications involving strong inducers of P-gp transport proteins.