Methodology & data sources

The drug name search is powered live by the RxNorm API from the US National Library of Medicine. RxNorm contains nearly every prescription and over-the-counter medication marketed in the United States, including generic names, brand names, dosage forms, and ingredient codes.

When supplementary product information is needed (route, dosage form, label highlights) we pull it from openFDA, the US Food and Drug Administration's public API.

Neither RxNorm nor openFDA publishes structured onset / Tmax / duration numbers in a machine-readable way. Those three fields on MedTime are a separate curated table maintained by us, currently covering roughly 100 of the most commonly prescribed and most commonly asked-about medications.

For each medication we cross-reference public pharmacology references — typically the FDA-approved package insert (DailyMed), authoritative clinical references such as the AHFS Drug Information monographs, and standard textbooks of pharmacology — and record a representative population range for a typical adult dose of the most common formulation.

When a drug exists in RxNorm but isn't in our timing table yet, the detail page shows a clear "timing data not yet available" message instead of guessing.

• Onset of effect — when a patient or clinician would typically notice the intended effect from a single dose. This is a clinical measure.
• Tmax (peak blood level) — when the drug's blood/plasma concentration reaches its maximum after a single dose. This is a pharmacokinetic measure. Tmax can be earlier than the felt onset (e.g. clopidogrel — Tmax is <1 hour, but meaningful platelet inhibition takes hours) or later (e.g. lisinopril).
• Duration of effect — approximately how long one dose continues to produce its intended effect.
• Cumulative therapeutic effect — when the meaningful benefit only builds over days or weeks of repeated dosing (statins, SSRIs, levothyroxine, amlodipine, etc.), we surface that separately as a short note rather than burying it in "onset". Some long-acting drugs (e.g. insulin glargine, insulin degludec) are marked as peakless, meaning they produce a steady level without a meaningful blood-concentration peak.

• Population ranges, not personal predictions. Every number is a typical-adult range. Yours may differ.
• One typical formulation per entry. Extended-release, IV, sublingual and other formulations have meaningfully different timing — we list the most common one and note variants where helpful.
• Onset and Tmax are different things. We never conflate the two; if a drug has a meaningful gap between them, the entry reflects that.
• Explicit "not yet available" beats guessing. If we don't have curated timing data for a drug, the app says so.
• Transparent and improvable. Anyone can propose a correction or new entry via the Suggest a medication page.
• Educational only. Nothing on this site is medical advice — see the disclaimer.

MedTime is focused on US-marketed medications because that's what RxNorm covers and what most of our timing references describe. International brand names, doses, and formulations may differ. Timing for paediatric, geriatric, pregnant, renally impaired or hepatically impaired patients can differ substantially from the ranges shown here.