Date of report 13 May 2021
Reported case interaction between
Efavirenz and Ginkgo biloba

FLS Science

Drugs suspected to be involved in the DDI

Victim
Efavirenz
Daily Dose
600 (mg)
Dose adjustment performed
No
Administration Route
Oral
Start date
Unknown
End date
Unknown
Perpetrator
Ginkgo biloba
Daily Dose
480 (mg)
Dose adjustment performed
No
Administration Route
Oral
Start date
Unknown
End date
Unknown

Complete list of drugs taken by the patient

Antiretroviral treatment
Efavirenz
Abacavir/Lamivudine
Complete list of all comedications taken by the patient, included that involved in the DDI

Ginkgo biloba

Clinical case description

Gender
Male
Age
47
eGFR (mL/min)
>60
Liver function impairment
No
Description

47 years old HIV+ male. HIV-1 infection was diagnosed in 2017. Soon after cART was initiated with efavirenz (600 mg, QD) + abacavir/lamivudine (600/300 mg, QD), achieving undetectable HIV-1 RNA and CD4+ T-cells count above 700 cells/mm3. In May and June 2019 he presented with low level viremia (HIV-1 RNA 210 copies/mL and 230 copies/mL, respectively). Due to anxiety, patient reported herbal supplement/medication intake, namely Ginkgo biloba (160 mg, 3 times per day). TDM was performed and the efavirenz plasma Ctrough was 873, 19 ng/mL. The physician indicated to withdraw this herbal supplement and 3 months later plasma HIV-1 RNA returned to undetectable.

Clinical Outcome

Loss of efficacy

Drug Interaction Probability Scale (DIPS)

Score
5 - Probable

Editorial Comment

Coadministration is not recommended as efavirenz concentrations may be decreased (as it occurred in this clinical case) due to potential induction of CYP3A4 or CYP2B6 by Gingko biloba. A similar case report also described lower efavirenz plasma concentrations in a patient who started taking Gingko biloba, which coincided with an increasing viral load. Interaction of Ginkgo biloba with efavirenz. Wiegman DJ, Brinkman K, Franssen EJF. AIDS, 2009, 23(9): 1184-1185.

University of Liverpool Recommendation

Potential interaction - may require close monitoring, alteration of drug dosage or timing of administration
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