Half-Life — What It Means in Clinical Trials
Plain English Definition
Half-life is the time it takes for the amount of drug in your body to decrease by half. A drug with a short half-life leaves your body quickly and may need to be taken multiple times a day. A drug with a long half-life stays in your system longer and might only need to be taken once a week or less.
Why It Matters
Half-life affects how often you take your medication and how long side effects might last. If a drug has a long half-life and you experience a side effect, it may take longer for that side effect to go away after stopping the drug.
Example
A trial drug might have: "A half-life of approximately 21 days, allowing for once-monthly dosing." This means less frequent visits to the clinic.
Need help understanding eligibility criteria?
How to Read Eligibility Criteria →