OverviewDosageSide EffectsInteractionsHalf-Life

Doxepin was the 240th most commonly prescribed drug in the United States in 2017. In that year alone, there were over two million prescriptions. Considering how popular this drug is right now, it pays to know a little bit more about this medication, including how long doxepin stays in your system.

Basic Information

Mean effective half-life: 17 hours

Time to steady-state: 7 days

Mean accumulation ratio: N/A

Terminal phase half-life: 15.3 hours

Doxepin has an oral bioavailability of 29 percent. It is well-absorbed via the gastrointestinal tract and excreted primarily in the urine. 


What is the half-life of doxepin?

The half-life for doxepin ranges from 15 to 17 hours

How long does doxepin stay in your system?

Doxepin is detectable in your system for the following time frames:

  • Your blood: not defined.
  • Your saliva: not defined.
  • Your urine for 75 hours after discontinuation of treatment
  • Your hair for at least five months

Blood tests do not usually test for doxepin because it can cause a false positive for amphetamines. It is not commonly looked for in saliva, either. Most often, urine and blood tests are the standard for detecting medications like doxepin, and at least one study did test for it in hair samples. 

How long does it take for doxepin to work for sleep?

People generally become sleepy quite quickly after taking doxepin, and will likely remain asleep for up to eight hours. With this fact in mind, it is better to take this medication 30 minutes or less before bed. 

Typically, patients see improvement in sleep within the first few days of taking this medication. Anyone that is still struggling after seven to 10 days should contact their primary care provider. 

Does doxepin make you sleepy the next day?

Some people experience sleepiness the next day if they take doxepin right after a meal, as high fat meals may delay effects of the tablet formulation of doxepin. Try to take the medication 30 minutes before bed, and don’t take it unless you can commit at least eight hours to sleep. 

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

More about Doxepin


Written by

Fact Checked by