Date of report 11 Jul 2022

Reported case interaction between
Darunavir and Melissa officinalis

This is a case of a male MSM patient, 50 years old, Caucasian, with no liver and kidney impairment, high 180 cm, weight 96 kg, BMI=29.6 kg/m² (overweight). Since 2017, he is on his current antiretroviral treatment, as follows: darunavir/cobicistat (Rezolsta^®) plus emtricitabine/tenofovir disoproxil fumarate (200/300 mg QD). Since the introduction of the current treatment, he was undetectable and his CD4 T-cells count was over 600 cells/mm³. In 2019 he was diagnosed with Metabolic syndrome. In August 2019, together with his standard antiretroviral treatment decided to take an herbal supplement lemon balm (Melissa officinalis), known as a herbal supplement for the treatment of insulin resistance and dyslipidemia. He refused antidiabetic treatment, as well as lipid-lowering agents. He started a diet and become much more physically active and stopped smoking. He was taking lemon balm tablets 300 mg BID standardized to 7% Rosmarinic acid and 14% Hydroxycinnamic acids (BID). According to the literature review, there were not much data about DDIs in humans on cART taking lemon balm. Thus, after achieving a steady-state concentration of lemon balm, TDM was performed using validated high-performance liquid chromatography (HPLC) assay and it showed darunavir plasma concentration of C_trough = 521,519 ng/mL. So, we concluded that there is no clinically relevant drug-drug interaction between lemon balm and darunavir.