Date of report: 20 Jul 2020
Reported case interaction between
 Etravirine and Apixaban

FLS Science

Drugs suspected to be involved in the DDI

Drug A
Etravirine (Perpetrator)
Daily Dose
400 (mg)
Dose adjustment performed
No
Administration Route
Oral
Start date
Dec. 1, 2008
End date
Ongoing
Drug B
Apixaban (Victim)
Daily Dose
10 (mg)
Dose adjustment performed
Yes
Administration Route
Oral
Start date
Feb. 2, 2019
End date
Unknown

Complete list of drugs taken by the patient

Antiretroviral treatment
Etravirine
Emtricitabine/Tenofovir-DF
Complete list of all comedications taken by the patient, included that involved in the DDI
apixaban

Clinical case description

Gender
Male
Age
50
eGFR (mL/min)
>60
Liver function impairment
No
Description
50 year man durably suppressed on Truvada and Etravirine (HIV seroconversion in 2003 with V106I RT mutation, intolerant of EFV (CNS disturbance), borderline eGFR 68mls/min. 2019 presented with pleuritic chest pain and breathlessness, CT confirmed extensive bilateral pulmonary emboli. Since unprovoked pulmonary embolism, for lifelong anticoagulation, apixaban started at standard dosing 5mg bd for 1 week, then 2.5mg daily (prescriber unaware of potential DDI with etravirine). HIV team continued apixaban dosing at 5mg bd- heparin concentrations were therapeutic (1.37U/mL). However, dose subsequently dropped to recommended maintenance of 2.5mg daily- heparin concentrations were subtherapeutic at 0.59 U/mL. DDI considered likely, antiretrovirals changed to an integrase regimen.

Outcome

Loss of efficacy

Drug Interaction Probability Scale (DIPS)

Score
5 - Probable

Editorial Comment

Coadministration has not been studied. Apixaban is metabolized by CYP3A4 and to a lesser extent by CYP1A2, CYP2C8, CYP2C9 and CYP2C19. Etravirine could potentially decrease apixaban exposure resulting in diminished efficacy. In this situation, it may be recommended changing cART to unboosted integrase inhibitors, as in the present clinical case.