Development and evaluation of a drug–herb interaction alert system integrated into a hospital electronic health record

Concurrent use of herbal and conventional medicines increases the risk of significant drug–herb interactions (DHIs). This study aimed to develop and evaluate a curated, severity-stratified DHI alert system integrated into a hospital electronic health record (EHR). A before–after observational study was conducted at a general hospital in Thailand. The team developed an evidence-based DHI database from tertiary references and primary literature. The database was integrated into the Hospital Information for Windows EHR using alert tiers: major, requiring mandatory prescriber confirmation; moderate, requiring clinical rationale; and minor, displayed as a passive notification. During 24 months, 510,910 prescription encounters were recorded, of which 7,278 contained both conventional and herbal medicines. Overall, 544 DHI events were identified. The DHI event rate decreased from 312/239,684 encounters (0.13%) before implementation to 232/271,226 encounters (0.09%) after implementation ( p < 0.001). Following implementation, lower DHI co-prescribing rates and increased detection of lower-severity interactions were observed, reflecting improved prescribing safety processes.