Drug-Drug Interactions May Be Common With Ritonavir-Containing COVID-19 Therapy

Approximately one-third of adults in the United States who receive a ritonavir-containing regimen for COVID-19 infection may be at increased risk for potential drug-drug interactions, according to results of a study published in Clinical Therapeutics.

Investigators at Merck & Co., Inc. conducted a study to determine the prevalence and severity of potential drug-drug interactions with ritonavir-containing medication regimens in the era of COVID-19 infection. Data for this study were sourced from the National Health and Nutrition Examination Survey (NHANES), an ongoing cross-sectional survey that has been conducted in the US every 2 years since 1999. The prevalence and severity of potential drug-drug interactions between ritonavir and cytochrome P350 3A4 (CYP3A4)-mediated medications were assessed among a total of 15,685 participants.

The study population was weighted to be representative of the noninstitutionalized population of US adults. Among participants included in the final analysis, the mean age was 47.3 years, 51.8% were women, 62.8% were White, 59.7% had private insurance, and 81.2% had at least 1 risk factor for COVID-19 infection.

Overall, participants used a mean (SD) of 2.9 (1.8) medications with potential drug-drug interactions per person. When extrapolated to the entire US population, a mean (SD) of 2.5 (0.1) medications with potential drug-drug interactions per person were used. In addition, the prevalence of any potential drug-drug interactions with ritonavir-containing medications was 45.3%, with 29.3% of US adults estimated to have a major or contraindicated potential drug-drug interaction.

Stratified by drug class, statins were the most commonly used contraindicated drug. After excluding statins, 21.0% of the US population were estimated to be at increased risk for potential drug-drug interactions with use of ritonavir-containing medication regimens.

Stratified by race and ethnicity, the highest rates of potential drug-drug interactions were observed among non-Hispanic White individuals (32.7%), followed by non-Hispanic Black individuals (28.4%), individuals classified as non-Hispanic “other” (25.4%), and Hispanic individuals (19.3%). For individuals with at least 1 risk factor for COVID-19 infection, the rate of major or contraindicated potential drug-drug interactions was 34.5%.

For US adults aged 60 years and older, the rate of exposure to medications with major or contraindicated potential drug-drug interactions was 60.2%.

Further analysis was conducted among several subgroups, including those with cancer, severe heart conditions, cerebrovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, diabetes, HIV infection, major depressive disorder, and those receiving steroids or immunosuppressive agents. Results indicated that the prevalence of major or contraindicated potential drug-drug interactions due to ritonavir-containing medications was greater than 50% for each group.

This study may not be generalizable to the entire US population as no data were collected among individuals with dementia, tuberculosis infection, cystic fibrosis, or organ transplant recipients. In addition, some medications with known drug-drug interactions with ritonavir-containing regimens may not have been included in the analysis as medication data were collected via prescription review alone.

“Study findings emphasize the need for skilled assessment of pDDIs [potential drug-drug interactions] before prescribing or dispensing ritonavir-containing COVID-19 therapy,” the investigators noted. “Alternative therapies should be considered when DDIs preclude the use of ritonavir-containing therapy,” the investigators concluded.

Disclosures: This research was supported by Merck & Co., Inc. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Infectious Disease Advisor