About MedTime
A plain-English reference for how long common medications take to start working, when their blood levels peak, and how long their effects last.
What MedTime is
MedTime is a free educational tool that helps you make sense of medication timing. You can search for a drug by its generic name or a US brand name, see a simple visual timeline of its effect, and compare two or three medications side by side.
We don't sell anything, we don't store your medical information, and we don't replace a conversation with your doctor or pharmacist.
Who it's for
- Patients and caregivers trying to understand a medication they've been prescribed.
- Students learning the basics of clinical pharmacology.
- Clinicians who want a quick visual refresher between consults.
- Anyone curious about why some medications work in minutes and others take weeks.
The three numbers we show
When the patient would typically notice the intended effect from one dose. For some drugs this is minutes (a rescue inhaler), for others it's weeks (an SSRI).
When the drug concentration in the blood reaches its peak after one dose. This is a pharmacokinetic measure — it doesn't always line up with when you feel the effect.
Roughly how long one dose keeps working before it wears off.
For drugs whose benefit builds gradually — statins, SSRIs, levothyroxine, amlodipine — we also show a separate note explaining the cumulative therapeutic build-up, rather than cramming that into "onset".
Scope
Search is powered by the US National Library of Medicine's RxNorm database, so coverage focuses on medications available in the United States. Timing data is currently a curated set of ~100 of the most commonly used medications, with more added over time via the Suggest a medication page.
A note on accuracy
Every number on this site is an approximate population range. Real-world response depends on age, weight, genetics, kidney/liver function, formulation, food, other medications, and individual biology. Use MedTime as orientation — not as a decision-making tool. For anything that matters, ask a licensed clinician or pharmacist.
See the methodology and disclaimer for more.