Which tool is best for screening interactions between herbal supplements, anticancer agents?

The best available tool for detecting herb–drug interaction is Lexicomp, and the best free alternative is Medscape, suggests a study. However, the sensitivity and performance for detecting herb–drug interaction is far lower than for drug–drug interactions and quite poor overall.

“Several screening tools exist to detect drug–drug interactions, but their performance to detect herb–drug interactions is not known,” the authors said. “This study compared the performance of eight drug–drug interaction screening tools to detect herb–drug interaction with anticancer agents.

An assessment was carried out on the herb–drug interaction performance of four subscription (Micromedex, Lexicomp, PEPID, Facts & Comparisons) and free (Drugs.com, Medscape, WebMD, RxList) drug–drug interaction tools.

The authors determined the clinical relevance of each herb–drug interaction using Natural Medicine and each drug-drug interaction tool. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using descriptive statistics. Finally, the performance between subscription and free tools was compared using linear regression.

All tools showed poor sensitivity (<0.20) for screening interactions between herbal supplements and anticancer drugs. Lexicomp had the highest positive predictive value (0.98) and best overall performance score (0.54). Among free tools, Medscape showed the best performance (0.52).

The worst subscription tools were as good as or better than the best free tools. As a group, subscription tools outperformed free tools on all metrics. Using an average subscription tool would detect one additional herb–drug interaction for every 10 herb–drug interactions detected by a free tool.

“Further research is needed to improve herb–drug interaction screening performance,” the authors said.