Paxil Half-Life: Does Paroxetine Show Up On Drug Test?

Last Updated: December 18, 2019

Authored by Roger Weiss, MD

Also known as Seroxat, Paxil is a selective serotonin antidepressant widely used to treat post-traumatic stress disorder, panic attacks, social phobia, generalized anxiety disorder, and premenstrual dysphoric disorders. With a half-life of about 21-24 hours, Paxil can remain in the body for as long as five days for patients with an accommodating system.
Those whose body system can’t tolerate it for a long time would house it for 1-3 days, which is the average elimination period. Traces of Paxil can be detected in urine, blood, hair, and saliva within a few hours of use. This article aims to educate readers on paroxetine metabolism, and the half-life of paroxetine

How Long Paxil Stays In The System

It takes almost five days to stay in a person’s system depending on common factors like age, genetics, body mass, metabolic rate, and others. Is Paxil addictive nature familiar to most users? Well, yes. This is due to its harsh withdrawal symptoms mostly experienced by long term users. But generally speaking, it is rare for short term users to develop an addiction to the medication.

Blood Test

Blood tests can detect the presence of Paxil within a few hours of use. At this stage, it is pretty hard to specify how long paroxetine stays in the system or blood depending on individual factors like body mass, age, genetics, and hydration, but generally, paroxetine would remain present in the blood for a maximum of 24 hours.

Urine Test

While it can be hard to ascertain the exact duration paroxetine stays in the urine due to different factors. Generally, it would remain in the urine for about 1-3 days depending on the dosage taken. A significant factor that influences this is hydration. Since the urinary flow is greatly affected by hydration, the excretion speed of paroxetine in the urine is affected. But generally, paroxetine would not be detected in a urine test. This is because paroxetine is an antidepressant drug, and since antidepressants are not considered as drugs of abuse, urine screens are not designed to detect them. However, there may be cross-reactions that can produce false positive results.

Saliva Test

As with most drug sensitive tests, paroxetine will not be detected in a saliva drug test. Paroxetine might remain in the saliva for up to three days. However, this is not constant for everybody. This is due to several reasons. saliva test kit
Basal metabolic rate plays a significant role in the duration of paroxetine in the saliva. Individuals with high BMRs (Basal metabolic rates) tend to excrete certain drugs from their body faster than those with low BMRs. This is because those with high BMRs have lower body fat. Thus the amount of paroxetine that can be absorbed in the body tissue is small.

Hair Test

Seroxat would remain in the hair for about 16 months after use. However, just like the rest, detection of paroxetine in the hair shaft is almost not possible. Hair tests are carried out to detect the main drugs of abuse like cocaine, barbiturates, and methadone. Sexorat can only be detected using gas chromatography test, which is used rarely for specific medical purposes. This type is quite complicated and expensive for a standard pre-employment check.

Half-Life Of Paxil

The half-life of Paxil is approximated to be around 21-24 hours, depending on numerous factors. In essence, within 21 hours of use, 50% of the drug is removed from the body after stopping the medication. A patient who takes 40 mg of paroxetine would have 20mg of medicines left in the body after 21 hours. Excess consumption can make a person to experience paroxetine high.

Will Paxil Show Up On A Standard Pre-Employment Drug Test?

No, paroxetine is not a controlled substance, and therefore, it will not show on any standardized drug test. Standard 5 panels, 10 and 12 panels drug screens do not look out for antidepressants. Instead, only special toxicology tests can detect traces of paroxetine in the urine, blood, and saliva, and at this stage, it would detect paroxetine as an antidepressant.

False Positive Drug Test With Paxil

It is possible with Paxil, and it mostly happens with THC. A false positive test for THC occurs because paroxetine cross-react with the anti-THC monoclonal antibody used in some screening assays. The chemical structure of marijuana is broken down into some of the same components of paroxetine. Hence, the screening test isn’t always able to differentiate between an antidepressant drug like paroxetine and a well-abused drug like marijuana.

How To Remove Paxil From The System Faster

There are different methods of removing this drug from the body. However, in a bid to flush Paxil from the body, caution must be taken. Since Paroxetine uses are mostly to cure depression, making it a powerful antidepressant drug, swift removal from the body, especially for a long-term user, can result in severe health issues. The FDA describes Paxil withdrawal side effects as severe and prolonged—and treatable only by restarting the drug. Abrupt withdrawal also causes Paxil brain zaps, which ranges from flu-like symptoms to electric severe wave shock in the brain. But the following methods are the fastest ways to remove paroxetine from the system.

Taper off

The best and the fastest way to remove paroxetine from the system is to taper or reduce the dose of paroxetine. When the medicine is decreased over some time, the body hardly notices the declination in dosage and concentration. As this goes on, the body slowly adapts to the new dosage. This whole process should be done under the supervision of medical personnel.
pill cut into two parts

Stay hydrated

The need to stay hydrated cannot be overemphasized. Prolonged use of antidepressants results in constant dehydration which lay host to a plethora of side effects. For this reason, it is crucial to stay hydrated at all times. Doing this helps flush out paroxetine, chemicals, toxins, fats, and other unwanted items from the urine and system. The more water consumed, the faster it is to flush out paroxetine from the body.

Eat healthy food

Consuming healthy food is another way to flush out Paxil from the body. At this point, patients should avoid sugars and bad fatty foods, which are a significant obstacle to drug removal from the body. Listed below are foods to eat, which can help in Paxil detoxification.

  • Chia seeds and lemon – Helps to flush out impurities in the intestine.
  • Avocados, almonds – With the high presence of omega 3 fats in them, they help minimize food craving, which happens to be one of the side effects of Paxil.
  • Green leafy veggies, seaweed, etc. – Great source of fiber to flush out Paxil from the body and antioxidants to boost the body’s immune system
  • Yogurt – Probiotics in yogurt keep the digestive tracts happy and healthy.


For someone looking to flush out Paxil from the system quickly, regular activities is another method to try. Doing this eliminates Paxil remnant from the body through sweat. A patient who uses Paxil frequently would notice an increase in weight. Why does Paxil cause weight gain? Paxil causes weight gain as a result of an increase in appetite caused by the drug. By engaging in exercise, the body fights Paxil sedating nature, which tries to limit physical activities.


Sauna is another effective way to flush out Paxil from the body. It does not only flush out Paxil; it helps to free the body of other harmful toxins present. Through sauna, the body sweats a massive amount of perspiration, thereby eliminating unwanted waste products from the system. Various studies have proven the effectiveness of saunas when it comes to removing heavy metal toxins, PCBs, solvents, pharmaceuticals, and organic chemicals from the body.
Note that Paroxetine is a habit-forming substance that might require medical treatment for addiction. Do not hesitate to call any of the substance abuse rehabs in case of any signs of addiction.

Page Sources

  1. Gury C, Cousin F., Pharmacokinetics of SSRI antidepressants: half-life and clinical applicability,
  2. Chen R, Shen K, Hu P, Single- and multiple-dose pharmacokinetics and tolerability of a paroxetine controlled-release tablet in healthy Chinese subjects,

Published on: May 23rd, 2019

Updated on: December 18th, 2019

About Author

Roger Weiss, MD

Dr. Roger Weiss is a practicing mental health specialist at the hospital. Dr. Weiss combines his clinical practice and medical writing career since 2009. Apart from these activities, Dr. Weiss also delivers lectures for youth, former addicts, and everyone interested in topics such as substance abuse and treatment.


Leave a comment

  • Sam
    Hi I’ve been on paxil for 5 years at 10mg per day. Over the last year and a half I have gone from taking it every other day to every second day and so on until now where I take 10mg once a week when I start to feel the withdrawals. I am now going to completely stop and I was wondering if I’m likely to have any serve side effects?
  • Logan Bisher
    Will Paxil show up a false positive for THC
  • Geoff
    Hi ive been taking Paxil for early ejaculation prescribed by a doctor. I rarely take it twice in 8 weeks will this show up on a random chain of custody drug test?