The definition of the half-life of a drug is "The time required for the activity of a substance taken into the body to lose one half its initial effectiveness."


Antidepressants

          Serotonin-Specific  Reuptake Inhibitors

  Celexa ( Citalopram) - 35 hr.
  Lexapro (Escitalopram) - 30 hr.
  Prozac - (Fluoxetine) - 2-5 days
  Luvox (Fluvoxamine) - 16-20 hours
  Paxil, Paxil CR (Paroxetine) - 15-20 hours
  Zoloft (Sertaline) - 24 hours

          Miscellaneous Antidepressants

  Wellbutrin, Wellbutrin SR, Wellbutrin XL (Bupropion) - 4-24 hours
  Cymbalta (Duloxetine) - 12 hours
  Gepirone ER - I don't know
  Serzone (Nefazodone) - 2-18 hours
  Desyrel (Trazodone) - 4-9 hours
  Effexor and Effexor CR (Venlafaxine) - 5-10 hours


Heterocyclic Antidepressants

          Tertiary Amine Tricyclic Antidepressants

  Elavil, Endep (Amitriptyline) - 10-50 hr.
  Anafranil (Clomipramine) - 20-50 hr.
  Adapin, Sinequan (Doxepine) - 8-24 hr.
  Tofranil (Imipramine) - 5-25 hr.
  Surmontil (Trimipramine) - I don't know

          Secondary Amine Tricyclic Antidepressants

  Norpramin (Desipramine) - 12-24 hr.
  Pamelor, Aventyl ( Nortriptyline) - 18-44 hr.
  Vivactil (Protriptyline) - 50-200 hr.

          Tetracyclic Antidepressants

  Asendin (Amoxapine) - 8 hr.
  Ludiomil (Maprotiline) - 21-25 hr.
  Remeron (Mirtazapine) - 20-40 hr.


Monoamine Oxidase Inhibitors

  Nardil (Phenelzine) - I don't know
  Parnate (Tranylcypromine) - I don't know


Antipsychotics

        Atypical Antipsychotics

  Abilify (Aripiprazole) - 75-94 hours
  Clozaril (Clozapine) - 11 hours
  Risperdal (Risperidone) - 3-20 hours
  Zyprexa, Zydis (Olanzapine) - 21-50 hours
  Seroquel (Quetiapine) - 6 hours
  Geodon (Ziprasidone) - 4 hours


High-Potency Antipsychotics

  Prolixin (Fluphenazine) - 10-20 hours
  Haldol (Haloperidol) - 10-20 hours
  Orap (Pimozide) - 55 hours
  Navane (Thiothixene) - 10-20 hours
  Stelazine (Trifluoperazine) - 10-20 hours


Mid-Potency Antipsychotics

  Loxitane (Loxapine) - 5-15 hours
  Moban (Molindone) - 10-20 hours
  Trilafon (Perphenazine) - 10-20 hours


Low-Potency Antipsychotics

  Thorazine (Chlorpromazine) - I don't know
  Serentil (Mesoridazine) - 24-48 hours
  Mellaril (Thioridazine) - 10-20 hours


Anxiolytics (Benzodiazepines)

  Xanax (Alprazolam) - Up to 12 hours
  Libirium, Libritabs (Chlordiazepoxide) - 100 hrs.
  Klonopin (Clonazepam) - 20-50 hrs.
  Tranxene (Clorazepate) - 100 hrs.
  Valium (Diazepam) - 100 hrs.
  Ativan (Lorazepam) - 15 hrs.


Non-Benzodiazepine Anxiolytics

  BuSpar (Buspirone) - 2-11 hours
  Atarax, Vistaril (Hydroxyzine) - I don't know


Benzodiazepine Hypnotics

  Dalmane (Flurazepam) - 100 hrs.
  Resotril (Temazepam) - 10-12 hrs.
  ProSom (Estazolam) - 17 hrs.
  Doral (Quazepam) 100 hrs.
  Halcion (Triazolam) - 2-3hrs.


Non-Benzodiazepine Hypnotics

  Ambien (Zolpidem) - 2-3 hrs.
  Sonata (Zaleplon) - 1 hr.
  Benadryl (Diphenhydramine) - 1-4 hrs.
  Noctec, Somnote (Chloral Hydrate) - 8 hrs.


Barbiturates

  Amobarbital - 8-42 hrs.
  Pentobarital - 15-48 hrs.


Mood Stabilizers

  Lithium Carbonate - 20 hrs.
  Olanzapine-Fluoxetine Combination - I don't know


Anticonvulsants

  Tegretol (Carbamazepine) - I don't know
  Neurontin (Gabapentin) - 5-7 hrs.
  Lamictal (Lamotrigine) - 25 hours
  Trileptal (Oxcarbazepine) - I don't know
  Gabitril (Tiagabine) - 7-9 hours
  Topamax (Toperimate) - 21 hours
  Depakote, Depakote ER (Valproic Acid) - I don't know


Psychostimulants

  Dexedrine (Dextroamphetamine) - 8-12 hrs.
  Adderall, Adderall XR (Dextoamphetamine and Amphetamine) - I don't know
  Ritalin, Ritalin SR, Ritalin LA, Concerta, Metadate ER, Metadate CD, Focalin, Methylin, Methylin ER (Methylphenidate) - 6-8 hrs.
  Straterra (Atomoxetine) - 4 hours
  Provigil (Modafinil) - 15 hrs.
  Cylert (Pemoline) - 12 hrs.


Substance Dependence

  Subutex, Suboxone (Buprenorphine) - 37 hours
  Catapres, Catapres-TTS (Clonidine) - 12-16 hrs.
  Antabuse (Disulfiram) - 60-120 hrs.
  Dolophine, Methadose (Methadone) - 24-36 hrs.
  Revia (Naltrexone) - 13 hrs.
  Zyban (Bupropion) - 4-21 hr.


Cognitive Enhancers

  Aricept (Donepezil) - I don't know
  Reminyl (Galantamine) - 7 hours
  Exelon (Rivastigmine) - 1.5 hours
  Cognex (Tacrine) - I don't know
  Namenda (Memantine) - 60-80 hours


Antiparkinsonian Drugs

  Symmentrel (Amantadine) - 24 hours
  Cogentin (Benztropine) - 3-6 hours
  Akineton (Biperidon) - 4-6 hours
  Benadryl (Diphenhydramine) - 1-4 hrs.
  Artane (Trihexyphenidyl) - 4-6 hours