Toolkit · Medication references
Psychiatric medication half-life chart.
Typical adult half-lives for commonly-prescribed psychiatric medications, grouped by class, drawn from FDA labeling.
Medically reviewed by Shariq Refai, MD, MBA · Last reviewed July 10, 2026
Before you use this chart, please read.
Educational reference, not medical advice. Half-lives are typical adult values from FDA prescribing information. Real values vary with age, kidney and liver function, genetic variation in metabolism, drug interactions, and other clinical factors. Don't use this chart to make medication decisions on your own. Don't start, stop, switch, or taper any medication based on what you read here.
What half-life is. The half-life of a medication is the time it takes for its blood concentration to fall by half after a dose. In clinical practice, half-life is a rough guide to how long a drug stays in the body, how often to dose it, how noticeable a missed dose will be, and how easy or difficult a taper is likely to be. It's one input into medication planning, not a rule.
Metabolites matter. Some medications have active metabolites whose half-life differs from the parent drug, sometimes dramatically. Where relevant, both parent and metabolite are shown. Fluoxetine is a classic example, but so are venlafaxine, bupropion, risperidone, and cariprazine.
If in doubt, ask your prescriber. If you're in crisis, call or text 988 in the US.
Quick answer
Half-life predicts how long a medication stays in the body after a dose. Short-half-life drugs (a few hours) need frequent dosing and can produce noticeable withdrawal or "discontinuation" symptoms if stopped abruptly. Long-half-life drugs (days to weeks) self-taper somewhat, are more forgiving of missed doses, but take longer to reach steady state, wash out for interactions or switches, and reveal side effects. In psychiatric medications, half-lives span from about one hour (zaleplon) to weeks (cariprazine's active metabolite). Below is a chart by class.
Antidepressants.
SSRIs (selective serotonin reuptake inhibitors).
| Medication | Typical adult half-life | Note |
|---|---|---|
| Sertraline (Zoloft) | ~26 h | Active metabolite N-desmethylsertraline ~62 to 104 h; less clinically active than parent. |
| Fluoxetine (Prozac) | 1 to 4 days (parent); 7 to 15 days (norfluoxetine) | Long metabolite half-life means self-tapering and prolonged washout for switches / interactions. |
| Escitalopram (Lexapro) | 27 to 32 h | Once-daily dosing. |
| Citalopram (Celexa) | ~35 h | Dose ceiling for QT concern. |
| Paroxetine (Paxil) | ~21 h | Noticeable discontinuation syndrome, taper slowly. |
| Fluvoxamine (Luvox) | ~15 h | Strong CYP1A2 / 2C19 inhibitor; more drug interactions. |
SNRIs (serotonin-norepinephrine reuptake inhibitors) and related.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Venlafaxine (Effexor) | ~5 h parent; ~11 h active metabolite (O-desmethylvenlafaxine) | Short half-life produces well-known discontinuation syndrome, taper very slowly, especially at low doses. |
| Desvenlafaxine (Pristiq) | ~11 h | The active metabolite of venlafaxine as its own drug. |
| Duloxetine (Cymbalta) | ~12 h | Once-daily dosing typical; discontinuation syndrome possible. |
| Levomilnacipran (Fetzima) | ~12 h | Extended-release once daily. |
Other antidepressants.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Bupropion (Wellbutrin) | ~21 h parent; 20 to 37 h active metabolite (hydroxybupropion) | Available in IR, SR, and XL forms; XL is once-daily. |
| Mirtazapine (Remeron) | 20 to 40 h | Once-daily, usually at bedtime; sedating at lower doses. |
| Trazodone | ~3 to 9 h (biphasic) | Often dosed at bedtime for sleep; short daytime effect. |
| Vilazodone (Viibryd) | ~25 h | Take with food for adequate absorption. |
| Vortioxetine (Trintellix) | ~66 h | Long half-life; steady state ~2 weeks. |
Antipsychotics.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Aripiprazole (Abilify) | ~75 h; dehydro-aripiprazole ~94 h | Very long, takes ~2 weeks to reach steady state; effects persist after stopping. |
| Brexpiprazole (Rexulti) | ~91 h | Long half-life; once-daily. |
| Cariprazine (Vraylar) | 2 to 5 days parent; 1 to 3 weeks (DDCAR active metabolite) | Extremely long total-body persistence via metabolite, takes weeks to reach steady state and to wash out. |
| Olanzapine (Zyprexa) | ~30 h | Once-daily dosing; metabolic side-effect profile is prominent. |
| Quetiapine (Seroquel / Seroquel XR) | ~6 h (IR); ~7 h (XR) | IR typically twice daily; XR once daily. |
| Risperidone (Risperdal) | ~3 h (parent) + ~24 h (active metabolite 9-hydroxyrisperidone) | Effective half-life dominated by metabolite; once- to twice-daily dosing. |
| Paliperidone (Invega) | ~23 h | The 9-hydroxyrisperidone metabolite of risperidone marketed as its own drug. |
| Lurasidone (Latuda) | ~18 h | Take with a substantial meal (≥ 350 kcal) for adequate absorption. |
| Ziprasidone (Geodon) | ~7 h | Take with food (≥ 500 kcal) for adequate absorption. |
| Haloperidol (Haldol) | ~18 h (oral) | Long-acting injectable formulations have half-lives of weeks. |
Mood stabilizers.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Lithium | ~18 to 36 h | Longer in older adults and reduced renal function; steady state ~5 days. Narrow therapeutic window, level monitoring required. |
| Valproate / divalproex (Depakote) | 9 to 16 h | Serum-level monitoring routine; teratogenic, pregnancy warnings. |
| Lamotrigine (Lamictal) | ~25 h alone; dramatically shorter with carbamazepine; longer with valproate | Slow titration required to reduce Stevens-Johnson syndrome risk. |
| Carbamazepine (Tegretol) | 25 to 65 h initially; ~12 to 17 h after auto-induction (weeks) | Induces its own metabolism; monitor levels. |
| Oxcarbazepine (Trileptal) | ~2 h parent; ~9 h active metabolite (MHD) | Less enzyme induction than carbamazepine. |
Benzodiazepines.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Alprazolam (Xanax) | ~11 h | Rapid onset; short half-life produces prominent inter-dose withdrawal and difficult tapers. |
| Lorazepam (Ativan) | 10 to 20 h | No active metabolites; often preferred in elderly and hepatic impairment. |
| Clonazepam (Klonopin) | 20 to 50 h | Long half-life supports twice-daily dosing. |
| Diazepam (Valium) | 30 to 60+ h (parent); up to ~100 h (active metabolites) | Very long total-body persistence via metabolites like nordiazepam. |
| Temazepam (Restoril) | 8 to 15 h | Primarily used for sleep. |
| Oxazepam | 4 to 11 h | No active metabolites; preferred in hepatic impairment. |
Sleep medications.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Zolpidem (Ambien) | ~2.5 h (IR); ~2.8 h (CR) | Short half-life; morning residual effect uncommon at usual doses. |
| Eszopiclone (Lunesta) | ~6 h | Longer half-life, some patients report morning taste or grogginess. |
| Zaleplon (Sonata) | ~1 h | Very short, for sleep-onset difficulty rather than maintenance. |
| Ramelteon (Rozerem) | 1 to 2.6 h (M-II active metabolite) | Melatonin receptor agonist; not a controlled substance. |
| Suvorexant (Belsomra) | ~12 h | Dual orexin receptor antagonist; morning residual possible at higher doses. |
| Lemborexant (Dayvigo) | 17 to 19 h | Longer half-life orexin antagonist. |
| Trazodone (as sleep aid) | ~3 to 9 h | Often used off-label for sleep at low doses. |
| Doxepin (Silenor) | ~15 h | Low-dose formulation approved for sleep maintenance. |
Stimulants and ADHD medications.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Methylphenidate (Ritalin IR) | ~2 to 3 h | Extended-release forms extend clinical duration but not core half-life. |
| Amphetamine mixed salts (Adderall IR) | ~9 to 14 h (d-amphetamine); ~11 to 14 h (l-amphetamine) | XR extends absorption profile. |
| Lisdexamfetamine (Vyvanse) | < 1 h (prodrug); ~10 to 13 h (d-amphetamine) | Prodrug slowly converts to d-amphetamine in the body. |
| Atomoxetine (Strattera) | ~5 h (extensive metabolizers); ~24 h (poor metabolizers) | Non-stimulant; CYP2D6-dependent. |
| Guanfacine ER (Intuniv) | ~17 h | Non-stimulant; alpha-2A agonist. |
| Clonidine ER (Kapvay) | ~12 to 16 h | Non-stimulant; alpha-2 agonist. |
Anxiolytics and gabapentinoids.
| Medication | Typical adult half-life | Note |
|---|---|---|
| Buspirone (Buspar) | ~2 to 3 h | Needs multiple daily doses; onset for anxiety over weeks. |
| Hydroxyzine (Vistaril, Atarax) | ~20 h | Antihistamine used for anxiety and pruritus. |
| Gabapentin (Neurontin) | 5 to 7 h | Renally cleared; adjust in kidney disease. Often three-times-daily dosing. |
| Pregabalin (Lyrica) | ~6 h | Renally cleared; controlled substance (schedule V) in the US. |
How to actually use this chart.
Half-life tells you how long a medication stays in your body. It doesn't tell you what the medication is doing while it's there. For that part, PsychiatryRx has an interactive guide to how psychiatric medications work in the brain, covering the major classes on this chart.
- Missed doses. Very short-half-life drugs (alprazolam, zaleplon) miss quickly and noticeably. Very long-half-life drugs (fluoxetine, aripiprazole, cariprazine) forgive one or two missed doses without an obvious drop. Neither is a reason to change dosing without your prescriber.
- Steady state. A rule of thumb is that a drug reaches steady state after roughly 4 to 5 half-lives at a fixed dose. For most SSRIs this is a few days; for aripiprazole and cariprazine it's weeks.
- Tapering. Shorter-half-life drugs generally need slower or longer tapers because the daily concentration drop is larger. Paroxetine and venlafaxine are classic examples where a very gradual taper reduces discontinuation symptoms.
- Switching. Switching to or from long-half-life drugs (fluoxetine, cariprazine) requires longer washout, an important consideration for MAOI or other interaction risk.
- Drug interactions. Changes in metabolizing enzymes (from other drugs, from grapefruit juice, from genetic variation) can dramatically change half-life. The values here are typical, not universal.
What this chart isn't.
This is a reference of typical adult pharmacokinetic values from FDA labeling. It isn't a dosing chart, a treatment recommendation, or a substitute for the current FDA prescribing information for each medication or for your prescriber's clinical judgment. Individual variability is substantial. Use this to understand a prescription, not to modify one.
Sources.
- U.S. Food and Drug Administration. Drugs@FDA, search each drug for full prescribing information (labeling), the authoritative source for half-lives, indications, dosing, warnings, and interactions.
- MedlinePlus (U.S. National Library of Medicine). Drug information monographs.
- Stahl SM. Stahl's Essential Psychopharmacology, 5th ed. Cambridge University Press; 2021 (for class-level pharmacokinetic context; individual half-life values in this chart are drawn from FDA labeling).
Related resources.
Keep going in the network
Half-life is one number. These pages put it in context, drug by drug.
- The full half-life reference across psychiatric medications. PsychiatryRx
- Discontinuation syndromes, and why half-life predicts them. PsychiatryRx
- Benzodiazepines sorted by half-life. PsychiatryRx
- Fluoxetine, the long half-life example. PsychiatryRx
- Paroxetine, the short half-life example. PsychiatryRx
- Half-life, defined in plain language. Shrinktionary
How to cite this page
APA-style suggested citation:
Refai S. Psychiatric medication half-life chart. The Shrink Network Toolkit Library. Published July 10, 2026. Accessed [date]. https://shrinknetwork.com/toolkit/medication-half-life-chart/
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