Date of report 11 Jul 2022

Reported case interaction between
Efavirenz and Melissa officinalis

This is a case of female patient, 55 years old, Caucasian, with no liver and kidney impairment, high 165 cm, weight 88 kg, BMI=32.3 kg/m² (obese). HIV-1 infection was diagnosed in 2010 and soon after cART was initiated as follows: efavirenz (600 mg QD) + fixed-dose combination of two NRTIs: abacavir (ABC, 600 mg) and lamivudine (3TC,300 mg), achieving undetectable HIV-1 RNA and CD4+ T-cells count above 600 cells/mm³. In 2019, she was diagnosed with metabolic syndrome. Together with cART patient selfprescribed herbal supplement - lemon balm (Melissa officinalis), known as a herbal supplement for the treatment of insulin-resistance and dyslipidemia. She was taking lemon balm tablets 300 mg BID standardized to 7% Rosmarinic acid and 14% Hydroxycinnamic acids. According to the literature review, there were not much data about DDIs in humans on cART and lemon balm. Thus, we performed TDM using validated high-performance liquid chromatography (HPLC) assay and it has shown efavirenz plasma concentration of C_trough = 1907.349 ng/mL. Pharmacokinetic variability of the nonnucleoside reverse transcriptase inhibitor efavirenz has been documented in the literature and a plasma therapeutic range of 1000–4000 ng/mL has been established for the efavirenz. Thus, we concluded that there is no clinically relevant drug-drug interaction between lemon balm and efavirenz. Furthermore, in the same patient HIV RNA pVL was undetectable.