A short list of high-impact interactions causes a large share of food/med problems. Build patient-friendly timing rules and “safer swap” menus into your counseling and your software. Always defer to prescribers for medication changes.

High-yield interactions to bake into workflows

• Warfarin ↔ Vitamin K variability: Keep intake consistent rather than “avoid all greens.” Teach stable patterns and coordinate with INR monitoring (MedlinePlus; NIH ODS). (MedlinePlus, 2017; NIH ODS, 2021). MedlinePlusOffice of Dietary Supplements
• Grapefruit ↔ CYP-metabolized drugs: Certain statins, some calcium-channel blockers, and others carry label warnings; check the label and pharmacist; default to avoidance when flagged (FDA, 2021). U.S. Food and Drug Administration
• Levothyroxine ↔ calcium/iron/coffee timing: Separate by ~4 hours for Ca/Fe and dose on an empty stomach for predictable absorption (StatPearls; MedlinePlus). (Eghtedari & Correa, 2023; MedlinePlus, 2019). NCBIMedlinePlus
• Fluoroquinolones ↔ multivalent cations (Ca/Mg/Al): Chelation can severely reduce antibiotic bioavailability; avoid dairy/antacids around dosing per label (FDA-Ciprofloxacin label; Pitman et al., 2019). FDA Access DataPMC

Safer-swap counseling

• For patients on warfarin, co-design a weekly veg pattern that repeats (e.g., similar portions of leafy greens across days) and document it alongside INR checks (MedlinePlus, 2025). MedlinePlus
• For levothyroxine, offer breakfast coffee later or move L-T4 to bedtime with a consistent 3–4 h post-meal window (Eghtedari & Correa, 2023). NCBI
• For grapefruit flags, list alternative fruits (orange, apple, berries) and confirm with pharmacist if the specific drug is affected (FDA, 2021). U.S. Food and Drug Administration

Embed checks, not just lists

Automated prompts that (1) identify the drug, (2) explain the interaction in plain language, (3) propose timing or swaps, and (4) document the override improve safety and save time (FDA, 2018; Sutton et al., 2020). U.S. Food and Drug AdministrationPMC