How Long Does Doxepin Last In Your System?

In our latest question and answer, the pharmacist discusses how long doxepin lasts in your system and is detectable on a drug urine test,

Apr 10, 2018

Elle asked

I have been taking 50mg of Doxepin daily long term. Can you please tell me long is it detectable in the urine?


Doxepin may be detectable in the urine for up to 75 hours after discontinuation of treatment. Based on what we know about the drugs metabolism, uou should allow more than 3 days to pass after taking the last Doxepin dose for it to be untraceable in the urine.

How Long Doxepin Stays In Your System

Doxepin belongs to the drug class “tricyclic antidepressants.” Like other antidepressants, when you first start taking Doxepin, it takes 4-8 weeks to begin feeling its effects. This is because it has to build up in your body in order to work in treating depression.

Once the drug has been built up enough in your body, its effects should last continuously unless you miss multiple doses in a row.

The scientific phrase for how long it takes a drug to leave your body is referred to as the drugs’ “elimination half-life, or “half-life” for short. The half-life of a drug is the time it takes for 50% of the drug to leave your body.

From a clinical standpoint, if you stop taking a drug, it will take approximately 4-5 half-lives to be completely eliminated from your body. Since Doxepin has a half-life of 15 hours, it will be eliminated from your body (and undetectable in the urine) in 75 hours, or a little over 3 days, after you take the last dose.


  • Antidepressants take time to build up in your body which consequently means it takes some time for them to be cleared from your body as well.
  • Doxepin will take approximately 75 hours, or a little over 3 days, to be cleared from your body and undetectable in the urine.

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