Source-backed half-life profile
Alprazolam half-life calculator
Alprazolam sits in the benzodiazepine group where the obvious question is rarely just "what percent remains?"
Every curve begins at 100%. No dose or measured body concentration is assumed.
X-axis: elapsed time. Y-axis: modeled percentage of the relative starting point remaining. The shaded band shows the reported half-life range. This is a mathematical visualization, not a personal concentration estimate.
What a careful reader should notice first
The curve helps compare elimination speed, but sedation, tolerance, withdrawal, combinations, and individual metabolism sit outside the model.
Source angle
Labeling and pharmacokinetic sources are useful here because formulation, age, liver function, and co-medications can change the interpretation.
Do not use it for
Do not use this page for tapering, timing a dose, driving decisions, or judging combination risk.
Best next step
Compare with diazepam, clonazepam, and lorazepam to see why benzodiazepine half-life ranges matter.
Alprazolam: evidence and interpretation notes
Why this page uses 11.2 hours
US tablet labeling reports a mean plasma elimination half-life of 11.2 hours in healthy adults and an observed range from 6.3 to 26.9 hours. That spread matters more than the decimal point. The mean gives the chart one reproducible input; the range shows why it should not be read as a personal countdown.
A clinical pharmacokinetics review by Greenblatt and colleagues provides a useful cross-check. Across studies of single oral administration, the review describes typical elimination half-lives of 9 to 16 hours. The review and label point to the same general time scale without claiming that every participant followed the same curve.
| Evidence source | What it contributes | Important limit |
|---|---|---|
| DailyMed tablet labeling | The 11.2-hour mean and full 6.3-to-26.9-hour range | Label summaries are not individual predictions |
| Greenblatt clinical review | Typical single-dose values, metabolism, and factors associated with slower clearance | It synthesizes several study settings rather than one uniform experiment |
| PubChem identity record | Confirms compound identity and basic chemistry | It does not independently establish the half-life used here |
Metabolism makes the headline number a starting point
Alprazolam is cleared largely through hepatic oxidative metabolism. The Greenblatt review discusses alpha-hydroxyalprazolam and 4-hydroxyalprazolam as initial metabolites, generally present in plasma at much lower concentrations than the parent compound. That differs from a long-lived active metabolite dominating the profile, but it still means the parent-drug curve is not a map of every chemical species present.
The review reports reduced clearance in many older adults and in people with cirrhosis. It also describes changes in clearance with some co-administered medicines. HalfLifeDB does not turn those observations into correction factors because doing so would create individualized medical guidance from population data.
What the curve can clarify
The chart shows how an approximately 11-hour half-life produces a same-day decline with a meaningful tail. The shaded region uses the label’s reported range to show how much faster or slower the mathematical decline could look if another supported half-life were selected.
It cannot determine when sedation, memory effects, coordination changes, or withdrawal risk have ended. Those outcomes depend on exposure history, tolerance, other substances, health status, and pharmacodynamics. The careful conclusion is narrower: 11.2 hours is a defensible educational center point, and the published variability is too wide to treat it as a universal clock.
Reading this curve
HalfLifeDB uses 11.2 h as a representative input for Alprazolam. In the simplified model, about 22.6% remains after 24 hours and about 3% remains after five half-lives, or roughly 2.3 days.
This sits in the same-day range. The chart is useful for seeing the bend of the curve across a day or two, but it should not be treated as a personal clock. The curve is relative: it does not estimate a person's measured concentration, effects, impairment, or time to clearance.
benzodiazepine context
Benzodiazepine half-life estimates can be especially sensitive to active metabolites, redistribution, age, liver function, and repeated use.
- A long terminal half-life does not mean effects remain constant for the whole period.
- Shorter-acting entries can still have residual effects after the main subjective effects fade.
- Repeated exposure can create overlap that a single-dose curve does not show.
Alprazolam timeline checkpoints
| Elapsed time | Modeled remaining | Reading note |
|---|---|---|
| 12 h | 47.6% | Meaningful modeled decline, not near-zero |
| 24 h | 22.6% | Long-tail portion of the model |
| 2.0 days | 5.13% | Low modeled remainder, not a clearance guarantee |
| 3.0 days | 1.16% | Low modeled remainder, not a clearance guarantee |
| 5.0 days | 0.06% | Low modeled remainder, not a clearance guarantee |
Nearby profiles by half-life
These entries sit near Alprazolam within the benzodiazepine group when sorted by representative half-life. That makes them curve comparisons, not statements about equal potency, effects, or risk.
- Diazepam (30 h)
Pharmacokinetics at a glance
| Representative half-life | 11.2 h |
|---|---|
| Reported range | 6.3 h to 26.9 h |
| Curve type | Normalized, first-order decline |
Selection note: Product labeling reports a mean plasma elimination half-life of about 11.2 hours in healthy adults, with a 6.3-to-26.9-hour range.
Sources and evidence context
A linked record is not automatically proof of the displayed value. Study, labeling, review, and compound identity sources serve different purposes; notes below identify limitations when they are known.
- Research abstract Greenblatt DJ et al. Clinical pharmacokinetics of alprazolam (1993).Clinical review describing typical 9-to-16-hour values, metabolism, and population factors that reduce clearance.
- Official labeling DailyMed label: Alprazolam tablet.Official labeling used for the 11.2-hour mean and 6.3-to-26.9-hour range displayed on this page.
- Identity record PubChem Compound Summary: Alprazolam.Compound identity record; useful background, not independent support for the selected numerical value.
What this page does not answer
- It does not estimate impairment, intoxication, or fitness to drive.
- It does not predict urine, blood, saliva, or hair test results.
- It does not model repeated exposure, tolerance, withdrawal, or interactions.
- It does not replace clinician, pharmacist, toxicologist, or emergency guidance.
Continue with context
- All substance profiles
- Browse the benzodiazepine group
- Compare this curve
- Clearance and volume of distribution
- Bioavailability, route, and formulation
- Active metabolites and parent compounds
- First-order vs nonlinear kinetics
- Detection windows vs half-life
- Reading labels and source quality
Read the medical disclaimer, methodology, and profile review log before using the model for comparison.