Easily find out how long do drugs stay in your system. Enter a drug and dose, or see a demo.

Drug

?

Drug name on the graph. It can be anything, but half life for common drugs is auto-filled.

Dose

?

Amount of the drug taken.

Half-life

?

Half life of the drug (explained below).

Offset

?

How long after the first administration you took another dose. Optional.

Repeat the dose every hours to reach a steady state in ** doses** or . Concentration in your body will vary at ** - ** with an average of .

You will eliminate % of the drug in if you quit cold turkey.

Finally, a modern yet simple multiple drug half life calculator that is flexible enough to suit all your needs.

Use with ease

Skip unneeded research with half life suggestions. Just enter the drug and dose and get your results in seconds.

Combine drugs and doses

Add multiple ingestions for the same or different drugs. See how they accumulate and find the optimal dose.

Visualize results

Accurately determine how much drug is in your body after a certain time on a full-screen drug half life chart. Easily save or share it!

See why people return and choose this half life elimination calculator over others. Try it, and you will love it too!

This medication half life calculator is just what I need! The visualization makes titrating much easier and helps me avoid unpleasant side effects.

Charli

I love that this cumulative drug half-life calculator lets me see the build-up of multiple doses. Now I know with what level of meds in my body, I feel best.

Trentavious RIP Bankroll

Thank you for this! I finally found a drug test calculator that lets me track multiple drugs. And as a bonus, the site doesn't look from the 90s!

Gemma

This drug concentration calculator is an easy tool to determine the **amount of substance left in your system**. It does so by looking at the elimination half life of a medication.

Use it to keep constant levels of medicine in the body, or avoid unwanted interactions between substances.

Try a demo to get an idea of how it works. Or enter your data as follows:

**Drug**- drug name on the graph. It can be anything, but half life for common drugs is auto-filled.**Dose**- amount of the drug taken.**Half life**- half life of medicine. Select a drug from the list of suggestions to fill it out automatically.**Offset (optional)**- how long after the initial administration you took another dose.

You can add unlimited ingestions to **track multiple drugs or repeating doses** of the same one.

Once you enter the required data for at least one ingestion, the graph shows the results:

**Time**- how much time has passed since you've first taken the drug.**Residuals**- how much drug is left in your body.

Hover on the graph to get a precise amount of drug left at any time.

You can consider the drug eliminated when about 97% of it is gone. That's when most drugs no longer have any effect.

A drug's half life is an estimate of time it takes the **amount of drug in the body to reduce by half**. Now that you know the drug half life definition, let's continue to the exciting stuff!

If you took 200 mg of a drug with a half life of 1 hour:

- 100mg remains after 1 hours
- 50mg remains after 2 hours
- 25mg remains after 3 hours
- 12.5mg remains after 4 hours
- 6.25mg remains after 5 hours

Almost 97% of the drug is eliminated after 5 hours. This is usually enough to consider the drug's effects negligible.

As seen above, eliminating a drug takes **4 to 5 half lives**. Note that drug tests can detect the usage longer.

Doubling the dose increases the time to eliminate it by one half life.

After learning what does half life of a drug mean, let's look at how to use it.

Half life helps you evaluate how often to take the drug to maximize effects and minimize adverse reactions. You can maintain a **minimum effective level of drug in the body** by adjusting your doses or their frequency.

This is irreplaceable knowledge for tapering, titrating, or reaching a steady state.

When tapering, you gradually decrease the dose of medication to stop using it. Decrease it too quickly, and you experience withdrawals. But decrease it too slowly, and you suffer side effects unnecessarily long.

Titration increases the dose for maximum benefit without side effects.

The drug needs to remain at a constant level (be in a steady state) during treatment to produce the desired effect. It happens when you consume the same amount of drug that's eliminated from the body.

For all of the above, knowing how much of the drug is left in your body and how it compounds is necessary. With this knowledge, you **quickly establish a dose and administration schedule**.

You can also use the drug elimination calculator to simulate loading doses, as some drugs need weeks of taking to reach optimal levels in your body.

And last but not least, you can **limit drug interactions**, as you know how much drug is left in the body at the time of the second administration. This helps preserve drug efficacy and avoid unwanted side effects.

We use the following half-life of drug formula to calculate medication half life:

**x**- time on the graph.**y**- remaining amount of the drug at time x.**dose**- initial amount of the drug.**offset**- time since the first administration.**halfLife**- half life of medication (the time it takes to eliminate half of the drug).

The formula assumes exponential decay. The substance decreases by half over each interval, which equals its half-life. If the time is less than the offset, the remaining amount is considered 0.

But don't worry about the math, as calculating half life is simple with this drug accumulation calculator.

Here's a list of common drugs and their half lives. The **half life is auto-filled** when you select any of these drugs. You can adjust it if needed.

Drug | Average | Estimated range |
---|---|---|

Abilify | 4 days | 96 h |

Acebutolol | 3.5 h | 3 - 4 h |

Acetaminophen | 2.5 h | 1 - 4 h |

Acetylcysteine | 5.5 h | 5 - 6 h |

Acyclovir | 2.5 h | 2 - 3 h |

Adderall | 20.5 h | 7 - 34 h |

Adinazolam | 3 h | 3 h |

Adrenaline | 2.5 min | 2 - 3 min |

Advil | 1.75 h | 1.5 - 2 h |

Alcohol | 4.5 h | 4 - 5 h |

Aleve | 12 h | 12 h |

Alprazolam | 15 h | 10 - 20 h |

Alprostadil | 5 min | 5 min |

Amantadine | 30 h | 20 - 40 h |

Ambien | 2.5 h | 2 - 3 h |

Amfepramone | 5 h | 4 - 6 h |

Amikacin | 2.5 h | 2 - 3 h |

Amineptine | 2.5 h | 2.5 h |

Amiodarone | 66.5 days | 26 - 107 days |

Amisulpride | 12 h | 12 h |

Amitriptyline | 29.5 h | 8 - 51 h |

Amlodipine | 40 h | 30 - 50 h |

Amoxapine | 24 h | 24 h |

Amoxicillin | 1.5 h | 1 - 2 h |

Amphetamine | 20.5 h | 7 - 34 h |

Amphotericin | 15 days | 15 days |

Amprenavir | 9 h | 7 - 11 h |

Anafranil | 3 days | 72 h |

Anidulafungin | 45 h | 40 - 50 h |

Apomorphine | 45 min | 30 - 60 min |

Argatroban | 45 min | 39 - 51 min |

Aripiprazole | 4 days | 96 h |

Asendin | 24 h | 24 h |

Aspirin | 6 h | 3 - 9 h |

Atenolol | 6.5 h | 6 - 7 h |

Ativan | 15 h | 10 - 20 h |

Atomoxetine | 5 h | 5 h |

Atorvastatin | 14 h | 14 h |

Azilect | 3 h | 3 h |

Azithromycin | 2.8 days | 68 h |

Aztreonam | 1.5 h | 1 - 2 h |

Baclofen | 3 h | 2 - 4 h |

Benadryl | 12 h | 12 h |

Bentazepam | 3 h | 2 - 4 h |

Betamethasone | 45 h | 36 - 54 h |

Bethanechol | 30 min | 30 min |

Bismuth | 46.5 days | 21 - 72 days |

Bretazenil | 2.5 h | 2.5 h |

Bromazepam | 30 h | 20 - 40 h |

Bromocriptine | 24 h | 24 h |

Brotizolam | 4.5 h | 4 - 5 h |

Buprenorphine | 45 h | 20 - 70 h |

Bupropion | 21 h | 12 - 30 h |

BuSpar | 2.5 h | 2 - 3 h |

Buspirone | 2.5 h | 2 - 3 h |

Butalbital | 35 h | 35 h |

Cabergoline | 3 days | 72 h |

Caffeine | 7.5 h | 3 - 12 h |

Camazepam | 17.5 h | 6 - 29 h |

Cannabidiol | 25 h | 18 - 32 h |

Cannabis | 30.3 h | 1.6 - 59 h |

Capreomycin | 12 h | 12 h |

Carbamazepine | 30.5 h | 14 - 47 h |

Cardizem | 3.75 h | 3 - 4.5 h |

Carfentanil | 8 h | 8 h |

Carisoprodol | 2 h | 1 - 3 h |

Carvedilol | 8.5 h | 7 - 10 h |

Caspofungin | 10 h | 9 - 11 h |

CBD | 25 h | 18 - 32 h |

Cefuroxime | 1.5 h | 1 - 2 h |

Celexa | 35 h | 35 h |

Cephalexin | 1 h | 1 h |

Cetirizine | 8 h | 8 h |

Chlordiazepoxide | 17.5 h | 5 - 30 h |

Chlorpheniramine | 24 h | 21 - 27 h |

Chlorpromazine | 30 h | 30 h |

Chlorprothixene | 10 h | 8 - 12 h |

Chlorzoxazone | 1 h | 1 h |

Cialis | 17.5 h | 17.5 h |

Cinazepam | 60 h | 60 h |

Cinolazepam | 9 h | 9 h |

Ciprofloxacin | 4 h | 4 h |

Citalopram | 35 h | 35 h |

Clarithromycin | 3.5 h | 3 - 4 h |

Claritin | 8 h | 8 h |

Clindamycin | 3 h | 2 - 4 h |

Clobazam | 34 h | 8 - 60 h |

Clobenzorex | 12 h | 10 - 14 h |

Clomipramine | 3 days | 72 h |

Clonazepam | 39.5 h | 19 - 60 h |

Clonazolam | 14 h | 10 - 18 h |

Clonidine | 14 h | 12 - 16 h |

Clorazepate | 2 days | 48 h |

Clotiazepam | 4 h | 4 h |

Clotrimazole | 2 h | 2 h |

Cloxazolam | 3.8 days | 80 - 105 h |

Clozapine | 35 h | 4 - 66 h |

Clozaril | 35 h | 4 - 66 h |

Cocaine | 1 h | 1 h |

Codeine | 3 h | 3 h |

Compazine | 5 h | 4 - 8 h |

Coumadin | 40 h | 40 h |

Cyclobenzaprine | 22.5 h | 8 - 37 h |

Cycloserine | 12 h | 12 h |

Cyclosporine | 16.5 h | 6 - 27 h |

Cylert | 12 h | 12 h |

Cymbalta | 12 h | 12 h |

Cyproheptadine | 8.5 h | 8 - 9 h |

Dapoxetine | 1.5 h | 1.5 h |

Darvocet | 33 h | 30 - 36 h |

Delavirdine | 6.5 h | 2 - 11 h |

Delorazepam | 3.8 days | 80 - 105 h |

Depacon | 12.5 h | 9 - 16 h |

Depakene | 12.5 h | 9 - 16 h |

Depakote | 12.5 h | 9 - 16 h |

Depixol | 35 h | 35 h |

Desipramine | 33 h | 12 - 54 h |

Desoxyn | 20 h | 10 - 30 h |

Desvenlafaxine | 11 h | 10 - 13 h |

Desyrel | 8.5 h | 7 - 10 h |

Dexamethasone | 3 h | 3 h |

Dexbrompheniramine | 25 h | 25 h |

Dexedrine | 10 h | 9 - 11 h |

Dextroamphetamine | 10 h | 9 - 11 h |

Dextromethorphan | 3 h | 2 - 4 h |

Diamorphine | 4 min | 2 - 6 min |

Diazepam | 39.5 h | 32 - 47 h |

Diclofenac | 1.5 h | 1 - 2 h |

Dicloxacillin | 42 min | 42 min |

Dicyclomine | 3.5 h | 2 - 5 h |

Diethylpropion | 5 h | 4 - 6 h |

Diflunisal | 10 h | 8 - 12 h |

Digitoxin | 7 days | 4 - 10 days |

Digoxin | 42 h | 36 - 48 h |

Dihydrocodeine | 4 h | 4 h |

Dilaudid | 2.5 h | 2 - 3 h |

Diltiazem | 3.75 h | 3 - 4.5 h |

Diphenhydramine | 12 h | 12 h |

Disopyramide | 7 h | 4 - 10 h |

Divalproex | 12.5 h | 9 - 16 h |

DMT | 15 min | 15 min |

Donepezil | 75 h | 50 - 100 h |

Dostinex | 3 days | 72 h |

Dosulepin | 29.5 h | 14 - 45 h |

Doxepin | 16.5 h | 8 - 25 h |

Doxycycline | 20 h | 18 - 22 h |

Droperidol | 2 h | 2 h |

Duloxetine | 12 h | 12 h |

Duragesic | 22 h | 17 - 27 h |

Dutasteride | 31.5 days | 28 - 35 days |

Efavirenz | 47.5 h | 40 - 55 h |

Effexor | 11 h | 9 - 13 h |

Elavil | 29.5 h | 8 - 51 h |

Eldepryl | 10 h | 10 h |

Emsam | 21.5 h | 18 - 25 h |

Ephedrine | 4.5 h | 3 - 6 h |

Erenumab | 28 days | 28 days |

Escitalopram | 29.5 h | 27 - 32 h |

Esomeprazole | 1.5 h | 1 - 2 h |

Estazolam | 20.5 h | 10 - 31 h |

Eszopiclone | 6 h | 6 h |

Ethambutol | 24 h | 24 h |

Ethosuximide | 2.3 days | 50 - 60 h |

Ethyl | 4 days | 73 - 119 h |

Etizolam | 6 h | 6 h |

Etoricoxib | 22 h | 22 h |

Everolimus | 32 h | 26 - 38 h |

Felbamate | 17 h | 11 - 23 h |

Fentanyl | 7.5 h | 3 - 12 h |

Flecainide | 19.5 h | 12 - 27 h |

Flomax | 7 h | 5 - 9 h |

Flubromazepam | 6.7 days | 100 - 220 h |

Fluconazole | 35 h | 20 - 50 h |

Flucytosine | 4 h | 3 - 5 h |

Flumazenil | 1 h | 40 - 80 min |

Flunitrazepam | 22 h | 18 - 26 h |

Fluoxetine | 5 days | 4 - 6 days |

Flupenthixol | 35 h | 35 h |

Fluphenazine | 8.5 days | 7 - 10 days |

Flurazepam | 6 days | 40 - 250 h |

Flutazolam | 3.5 h | 3.5 h |

Flutoprazepam | 75 h | 60 - 90 h |

Fluvoxamine | 12.5 h | 12 - 13 h |

Fondaparinux | 19 h | 17 - 21 h |

Gabapentin | 6 h | 5 - 7 h |

Gabitril | 6.5 h | 5 - 8 h |

Ganciclovir | 4.5 h | 3 - 6 h |

Gentamicin | 2 h | 1 - 3 h |

Geodon | 7 h | 7 h |

Halazepam | 2.7 days | 30 - 100 h |

Halcion | 3.5 h | 1.5 - 5.5 h |

Haldol | 27.5 h | 14 - 41 h |

Haloperidol | 25.5 h | 14 - 37 h |

HCTZ | 22 h | 6 - 15 h |

Heparin | 4.5 h | 3 - 6 h |

Heroin | 4 h | 1 - 7 h |

Hydrochlorothiazide | 10.5 h | 6 - 15 h |

Hydrocodone | 5 h | 4 - 6 h |

Hydromorphone | 2.5 h | 2 - 3 h |

Hydroxychloroquine | 50 days | 1 - 2 mos |

Hydroxyzine | 22 h | 20 - 24 h |

Ibuprofen | 2 h | 1 - 3 h |

Imipramine | 13 h | 6 - 20 h |

Imovane | 5.5 h | 5 - 6 h |

Inapsine | 2 h | 2 h |

Indinavir | 2 h | 1 - 3 h |

Indomethacin | 7.5 h | 3 - 12 h |

Invega | 1 day | 23 h |

Isoniazid | 1.5 h | 1 - 2 h |

Itraconazole | 16 h | 14 - 18 h |

Ketamine | 1.5 h | 1 - 2 h |

Ketazolam | 2.7 days | 30 - 100 h |

Ketoconazole | 5 h | 2 - 8 h |

Klonopin | 39.5 h | 19 - 60 h |

Lacosamide | 13 h | 13 h |

Lamictal | 22.5 h | 15 - 30 h |

Lamotrigine | 22.5 h | 15 - 30 h |

Lansoprazole | 1.5 h | 1.5 h |

Leflunomide | 16 days | 14 - 18 days |

Levetiracetam | 7 h | 6 - 8 h |

Levitra | 4.5 h | 4 - 5 h |

Levocetirizine | 8 h | 6 - 10 h |

Levofloxacin | 7 h | 6 - 8 h |

Levorphanol | 13.5 h | 11 - 16 h |

Levothyroxine | 6.5 days | 3 - 10 days |

Lexapro | 29.5 h | 27 - 32 h |

Librium | 17.5 h | 5 - 30 h |

Lidocaine | 1.5 h | 1 - 2 h |

Lipitor | 14 h | 14 h |

Lisdexamfetamine | 10 h | 9 - 11 h |

Lisinopril | 12 h | 12 h |

Lithium | 22 h | 14 - 30 h |

Loperamide | 11.5 h | 9 - 14 h |

Lopinavir | 5 h | 4 - 6 h |

Loprazolam | 9 h | 6 - 12 h |

Lopressor | 5 h | 3 - 7 h |

Loratadine | 8 h | 8 h |

Lorazepam | 15 h | 10 - 20 h |

Lormetazepam | 11 h | 10 - 12 h |

Lortab | 5 h | 4 - 6 h |

Losartan | 2 h | 2 h |

Loxapine | 6 h | 4 - 8 h |

LSD | 4 h | 3 - 5 h |

Ludiomil | 3 days | 36 - 105 h |

Lupron | 3 h | 3 h |

Luvox | 12.5 h | 12 - 13 h |

Lyrica | 6.3 h | 6.3 h |

Manerix | 1.5 h | 1 - 2 h |

Maprotiline | 3 days | 36 - 105 h |

MDMA | 6 h | 4 - 8 h |

Medazepam | 5 days | 36 - 200 h |

Melatonin | 42.5 min | 35 - 50 min |

Meloxicam | 20 h | 20 h |

Meperidine | 3.5 h | 2 - 5 h |

Mephobarbital | 2 days | 48 - 52 h |

Meprobamate | 11.5 h | 6 - 17 h |

Mesoridazine | 1.5 days | 24 - 48 h |

Metformin | 6.5 h | 4 - 9 h |

Methadone | 37.5 h | 15 - 60 h |

Methamphetamine | 17.5 h | 5 - 30 h |

Methocarbamol | 1.5 h | 1 - 2 h |

Methotrexate | 6.5 h | 3 - 10 h |

Methylphenidate | 3.5 h | 2 - 5 h |

Metoprolol | 5 h | 3 - 7 h |

Metronidazole | 8 h | 8 h |

Micardis | 24 h | 24 h |

Midazolam | 2 h | 90 - 150 min |

Milnacipran | 8 h | 8 h |

Minocycline | 18.5 h | 12 - 25 h |

Mirapex | 10 h | 8 - 12 h |

Mirtazapine | 30 h | 20 - 40 h |

Moclobemide | 1.5 h | 1 - 2 h |

Modafinil | 15 h | 15 h |

Molindone | 1.5 h | 90 min |

Morphine | 4 h | 1 - 7 h |

Muse | 5 min | 5 min |

Mycophenolic | 13 h | 8 - 18 h |

Naloxone | 1.5 h | 1.5 h |

Naltrexone | 13 h | 13 h |

Naproxen | 18 h | 12 - 24 h |

Navane | 15 h | 10 - 20 h |

Nefazodone | 3 h | 2 - 4 h |

Nelfinavir | 4.5 h | 4 - 5 h |

Neostigmine | 1 h | 50 - 90 min |

Neurontin | 6 h | 5 - 7 h |

Nevirapine | 27.5 h | 25 - 30 h |

Nexium | 1.5 h | 1 - 2 h |

Nicotine | 1.5 h | 1 - 2 h |

Nimesulide | 3.5 h | 2 - 5 h |

Nimetazepam | 22 h | 14 - 30 h |

Nitrazepam | 32.5 h | 17 - 48 h |

Nordiazepam | 5 days | 36 - 200 h |

Norpramin | 33 h | 12 - 54 h |

Nortriptyline | 53 h | 16 - 90 h |

Nucynta | 4 h | 4 h |

Ofloxacin | 8.5 h | 8 - 9 h |

Olanzapine | 37.5 h | 21 - 54 h |

Omeprazole | 1 h | 1 h |

Ondansetron | 5.7 h | 5.7 h |

Opana | 8 h | 7 - 9 h |

Oxazepam | 7.5 h | 4 - 11 h |

Oxcarbazepine | 3 h | 1 - 5 h |

Oxycodone | 4 h | 3 - 5 h |

OxyContin | 4 h | 3 - 5 h |

Oxymorphone | 8 h | 7 - 9 h |

Paliperidone | 1 day | 23 h |

Pamelor | 53 h | 16 - 90 h |

Pantoprazole | 1.5 h | 1 - 2 h |

Parlodel | 24 h | 24 h |

Parnate | 2.5 h | 2 - 3 h |

Paroxetine | 21 h | 21 h |

Paxil | 21 h | 21 h |

Pemoline | 12 h | 12 h |

Penicillin | 28 h | 30 min-56h |

Pentazocine | 3.6 h | 1.5 - 10 h |

Pentobarbital | 31.5 h | 15 - 48 h |

Percocet | 4 h | 3 - 5 h |

Pergolide | 27 h | 27 h |

Periactin | 8.5 h | 8 - 9 h |

Perphenazine | 14 h | 8 - 20 h |

Pethidine | 3.5 h | 2 - 5 h |

Phenazepam | 2.5 days | 60 h |

Phendimetrazine | 21.5 h | 19 - 24 h |

Phenelzine | 12 h | 12 h |

Phenobarbital | 4 days | 81 - 117 h |

Phentermine | 25 h | 25 h |

Phenylephrine | 3 h | 2.5 - 3.5 h |

Phenytoin | 20 h | 18 - 22 h |

Pimozide | 2.3 days | 55 h |

Pinazepam | 3 days | 40 - 100 h |

Piribedil | 4.2 h | 1.7 - 6.7 h |

Posaconazole | 34.5 h | 32 - 37 h |

Pramipexole | 10 h | 8 - 12 h |

Prazepam | 5 days | 36 - 200 h |

Prednisone | 27 h | 18 - 36 h |

Pregabalin | 6.3 h | 6.3 h |

Premazepam | 11.5 h | 10 - 13 h |

Prevacid | 1.5 h | 1 - 2 h |

Prilosec | 1.5 h | 1 - 2 h |

Primidone | 5 h | 3 - 7 h |

Pristiq | 11 h | 10 - 13 h |

Procainamide | 3.5 h | 2 - 5 h |

Prochlorperazine | 5 h | 4 - 8 h |

Prolixin | 15 h | 15 h |

Promazine | 6 h | 6 h |

Promethazine | 17.5 h | 16 - 19 h |

Propafenone | 6 h | 2 - 10 h |

Propoxyphene | 33 h | 30 - 36 h |

Propranolol | 4 h | 2 - 6 h |

Prostigmin | 1 h | 50 - 90 min |

Protriptyline | 3 days | 54 - 92 h |

Provigil | 15 h | 15 h |

Prozac | 5 days | 4 - 6 days |

Pseudoephedrine | 6 h | 4 - 8 h |

Psilocybin | 2.7 h | 100 - 220 min |

Pyrazinamide | 9.5 h | 9 - 10 h |

Pyrazolam | 17 h | 16 - 18 h |

Quazepam | 79.5 h | 39 - 120 h |

Quetiapine | 7 h | 7 h |

Quinidine | 7 h | 5 - 9 h |

Rabeprazole | 1.5 h | 1.5 h |

Ranexa | 1.65 h | 1.4 - 1.9 h |

Ranitidine | 2.5 h | 2 - 3 h |

Ranolazine | 1.65 h | 1.4 - 1.9 h |

Rasagiline | 3 h | 3 h |

Reboxetine | 12 h | 12 h |

Remeron | 30 h | 20 - 40 h |

Restoril | 11.5 h | 8 - 15 h |

Requip | 5.5 h | 5 - 6 h |

Rifabutin | 42.5 h | 16 - 69 h |

Rifampin | 2.5 h | 2 - 3 h |

Rilmazafone | 10.5 h | 10 - 11 h |

Risperdal | 20 h | 20 h |

Risperidone | 20 h | 20 h |

Ritalin | 3.5 h | 2 - 5 h |

Ritonavir | 4 h | 3 - 5 h |

Rivaroxaban | 7 h | 5 - 9 h |

Robitussin DM | 4.5 h | 3 - 6 h |

Ropinirole | 5.5 h | 5 - 6 h |

Roxicodone | 4 h | 3 - 5 h |

S-Adenosyl | 1.6 h | 100 min |

Salicylate | 2.5 h | 2 - 3 h |

SAM-e | 1.6 h | 100 min |

Saquinavir | 12 h | 9 - 15 h |

Savella | 8 h | 8 h |

Secobarbital | 25.5 h | 22 - 29 h |

Selegiline | 21.5 h | 18 - 25 h |

Seroquel | 7 h | 7 h |

Sertindole | 3 days | 3 days |

Sertraline | 29 h | 13 - 45 h |

Serzone | 3 h | 2 - 4 h |

Sibutramine | 15 h | 14 - 16 h |

Sildenafil | 3.5 h | 3 - 4 h |

Simvastatin | 2.5 h | 2 - 3 h |

Sinequan | 16.5 h | 8 - 25 h |

Sirolimus | 2.6 days | 46 - 78 h |

Sodium | 12.5 h | 9 - 16 h |

Solian | 12 h | 12 h |

Soma | 2 h | 1 - 3 h |

Sonata | 75 min | 60 - 90 min |

Stablon | 3 h | 3 h |

Stelazine | 15 h | 10 - 20 h |

Strattera | 5 h | 5 h |

Streptomycin | 5.5 h | 5 - 6 h |

Suboxone | 45 h | 20 - 70 h |

Subutex | 45 h | 20 - 70 h |

Sufentanil | 4.4 h | 4.4 h |

Sulfamethoxazole | 10 h | 10 h |

Sulfasalazine | 7.5 h | 5 - 10 h |

Sulpiride | 7 h | 6 - 8 h |

Survector | 2.5 h | 2.5 h |

Symbyax | 5 days | 4 - 6 days |

Symmetrel | 30 h | 20 - 40 h |

Synthroid | 7 days | 7 days |

Tacrolimus | 19.5 h | 4 - 35 h |

Tadalafil | 17.5 h | 17.5 h |

Talwin | 3.6 h | 1.5 - 10 h |

Tamsulosin | 6 h | 5 - 7 h |

Tapentadol | 4 h | 4 h |

Tegretol | 30.5 h | 14 - 47 h |

Telmisartan | 24 h | 24 h |

Temazepam | 14 h | 8 - 20 h |

Tenuate | 5 h | 4 - 6 h |

Tetracycline | 9 h | 7 - 11 h |

Tetrahydrocannabinol | 30.3 h | 1.6 - 59 h |

Tetrazepam | 14.5 h | 3 - 26 h |

Theophylline | 9 h | 7 - 11 h |

THC | 30.3 h | 1.6 - 59 h |

Thienalprazolam | 25 h | 10 - 40 h |

Thioridazine | 22.5 h | 21 - 24 h |

Thiothixene | 15 h | 10 - 20 h |

Thorazine | 30 h | 30 h |

Tiagabine | 6.5 h | 5 - 8 h |

Tianeptine | 3 h | 3 h |

Tizanidine | 2.5 h | 2.5 h |

Tobramycin | 2 h | 2 h |

Tofranil | 13 h | 6 - 20 h |

Topamax | 22 h | 19 - 25 h |

Topiramate | 22 h | 19 - 25 h |

Tramadol | 7 h | 6 - 8 h |

Tranxene | 2 days | 48 h |

Tranylcypromine | 2.5 h | 2 - 3 h |

Trazodone | 8.5 h | 7 - 10 h |

Triazolam | 3.5 h | 1.5 - 5.5 h |

Trifluoperazine | 15 h | 10 - 20 h |

Trilafon | 14 h | 8 - 20 h |

Trileptal | 3 h | 1 - 5 h |

Trimethoprim | 10 h | 8 - 12 h |

Trimipramine | 27.5 h | 16 - 39 h |

Surmontil | 27.5 h | 16 - 39 h |

Truxal | 10 h | 8 - 12 h |

Tylenol | 2.5 h | 1 - 4 h |

Ultram | 6.5 h | 6 - 7 h |

Uprima | 45 min | 30 - 60 min |

Urecholine | 30 min | 30 min |

Valium | 39.5 h | 32 - 47 h |

Valproic | 12.5 h | 9 - 16 h |

Vancomycin | 7.5 h | 4 - 11 h |

Vardenafil | 4.5 h | 4 - 5 h |

Venlafaxine | 11 h | 9 - 13 h |

Viagra | 3.5 h | 3 - 4 h |

Vibramycin | 20 h | 18 - 22 h |

Vicodin | 5 h | 4 - 6 h |

Vivactil | 3 days | 54 - 92 h |

Voltaren | 1.5 h | 1 - 2 h |

Voriconazole | 7.5 h | 6 - 9 h |

Vyvanse | 10 h | 9 - 11 h |

Warfarin | 40 h | 20 - 60 h |

Weed | 30.3 h | 1.6 - 59 h |

Wellbutrin | 21 h | 12 - 30 h |

Xanax | 15 h | 10 - 20 h |

Xarelto | 7 h | 5 - 9 h |

Yohimbine | 1.4 h | 15 - 150 min |

Zaleplon | 75 min | 60 - 90 min |

Ziprasidone | 7 h | 7 h |

Zocor | 2 h | 2 h |

Zofran | 5.7 h | 5.7 h |

Zoloft | 29 h | 13 - 45 h |

Zolpidem | 2.5 h | 2 - 3 h |

Zonisamide | 2.6 days | 53 - 75 h |

Zopiclone | 5 h | 4 - 6 h |

Zotepine | 15 h | 14 - 16 h |

Zyprexa | 37.5 h | 21 - 54 h |

Zyrtec | 7.5 h | 6 - 9 h |

These values are estimates. The actual half life varies, depending on many user and drug-related variables.

Yes, the half life of drugs varies depending on 2 large groups of factors:

First, **patient-specific variables** can affect half life:

- Gender
- Age
- Race or genetics (can influence metabolism)
- Blood circulation
- Diet (for example, grapefruit juice)
- Excessive or low fluid levels
- History of previous drug use
- Kidney function (for drugs cleared via the kidneys)
- Liver function (for drugs metabolized through the liver)
- Obesity
- Pre-existing conditions (for example, heart failure)
- Presence of other drugs
- Smoking
- Other variables

And the other set of factors affecting half-life of drug are **drug-specific variables**:

- Formulation (for example, extended-release formulations)
- Behavior in the body (for example, zero-order pharmacokinetics)
- Administration method (for example, oral)
- Presence of metabolites or other drugs that may interact
- Clearance method (for example, via the liver)
- Place of accumulation (for example, in the fat)
- If the drug binds to proteins or not
- Properties (for example, molecule size)
- The volume of distribution
- Other variables

Drugs with short half life **act quickly**, but their **effects wear off faster**. They usually must be taken several times per day to achieve the desired result.

Such drugs are harder to withdraw from. That's why drug treatment programs often switch people from drugs with shorter half life to those in the same class with longer one.

Drugs with long half life **need longer to start working** but their **effects last longer**. They can be taken daily, weekly, monthly, or even less often! They're usually also milder.

These drugs are more likely to build up in your body over time. It happens if you take the drug more frequently than it's completely gone from your system. The medicine half life calculator helps you decrease the dose over time to keep the same amount of drug present.

As you may have noticed in the above table, **adrenaline** has one of the shortest half lives of only **2.5 minutes**. It clears from the body extremely quickly!

It's used in severe allergic reactions, and its dose sometimes has to be repeated due to the short half life.

**Amiodarone** is the drug with the longest half life among those we collected. It takes up to **107 days** for your body to get rid of only half of the dose taken.

It's used in some heart arrhythmias and resuscitation.

Half life is used to estimate how long does medicine stay in your body. That means **half of the drug is gone** from your body 4 hours after administration.

No. Half life is the time it takes half of the drug to be eliminated. Drug duration is the **overall time** the drug remains in the body.

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