Switching Paxil (Paroxetine) From Night To Morning Dosing

Paxil can cause insomnia and is recommended for morning administration.

Question

I am taking 20 mg of Paxil in the PM. What is the best way to switch to the AM? Thanks.

Asked by Chuck On Aug 21, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Aug 21, 2018
Morning Night Illustration

Overview

Paxil (paroxetine) is a selective serotonin reuptake inhibitor (SSRI) antidepressant. It is indicated for treatment in the following:

  • Major depressive disorder
  • Generalized anxiety disorder
  • Hot flashes
  • Menopause
  • Obsessive-compulsive disorder
  • Panic disorder
  • Posttraumatic stress disorder
  • Premenstrual dysphoric disorder
  • Social anxiety

It is recommended to be taken in the morning for most individuals, but nighttime dosing can be appropriate as well.


Many SSRI medications, including Paxil, are recommended to be taken in the morning as opposed to in the evening. Per the package insert for Paxil:

"PAXIL [paroxetine] should be administered as a single daily dose with or without food, usually in the morning."

The morning administration time recommendation for Paxil is due to the potential side effect of insomnia.

Taking Paxil at night can cause difficulty falling asleep and difficulty staying asleep. It has been reported that insomnia occurs in 8 to 24% of individuals on Paxil.

In fact, nearly all SSRI medications, which also includes includes Zoloft, Prozac, Celexa and Lexapro, are associated with sleep disturbances. Specifically, it has been reported that the SSRI class overall can cause:

  • Increased sleep onset latency
  • Increased number of awakenings
  • An overall decrease in sleep efficiency.
  • Suppression of REM sleep

In most cases, sleep-related side effects will decrease the longer you are taking the medication.

However, there are times where they won't completely subside which may necessitate a change in the time of day you take your medication or a change in medication entirely.


Changing Dosing Time

For some individuals, switching Paxil to a morning administration time may help alleviate certain side effects, like insomnia.

Unfortunately, there is no "recommended" way to change the time you take Paxil, or any SSRI for that matter, from nighttime to the morning.

For some drugs, it is extremely important to not miss, or allow too much time to pass between doses. Examples include antibiotics, antiretrovirals, and anti-Parkinson's drugs.

Allowing too much time to elapse could potentially cause drug levels to fall too low, decreasing the efficacy of the medications.

For the example of antibiotics, it could lead to your infection not being appropriately treated. In the case of anti-Parkinson's drugs, it could lead to a return or exacerbation of symptoms.

However, when it comes to antidepressants, in general, you don't want to double up or take more than your usual dose in a 24 hours period (if you take one tablet daily).

It is important to discuss with your doctor how to best adjust the time to earlier in the day. In most cases, they will recommend to:

  • Skip your usual nighttime dose and simply take your next dose at your desired time in the morning. This means that more than 24 hours will elapse between doses.

The good news regarding Paxil is that it stays in your body for an extended period of time due to its long half-life, around 21 hours.

This means that it takes around 21 hours for drug levels to be reduced by 50% in your system. Paxil will still be in your system even after missing/skipping one dose.

In addition, consistent use of SSRI medication is thought to produce long-lasting changes to receptors in the brain and neurotransmitter release, which generally won't be much affected by one missed dose of Paxil.

As Paxil has a longer half-life (it will still be present in the body even after a missed dose), and the fact that SSRI use causes significant changes in the brain that aren't immediately reversed with one missed dose, it is unlikely changing your administration time on a one-time basis will have significant effects.

Nevertheless, as stated above, you should speak with your doctor regarding the best way to change the administration time of Paxil for your particular situation.


Summary

  • There is no single recommended way to change your dosing time from evening to morning (the recommended time to take the drug).
  • However, one method involves delaying your usual nighttime dose until the next morning.
  • Speak with your doctor about the best method to switch dosing times for your particular medical situation.

  • References
    1. Mechanism of Paroxetine (Paxil) Inhibition of the Serotonin Transporter. Nature
    2. Brain Structural Effects of Antidepressant Treatment in Major Depression. PubMed
    3. [Paroxetine: pharmacokinetics and pharmacodynamics]. PubMed
    4. The effect of commonly used antidepressant drug groups on sleep profile with major depression: a case–control study. LWW
    5. The Effects of Antidepressants on Sleep in Patients with Depression. SAGE
    6. Effects of Antidepressants on Sleep. PubMed
    7. Effectiveness of paroxetine in the treatment of acute major depression in adults: a systematic re-examination of published and unpublished data from randomized trials. PubMed
    8. Paxil Prescribing Information. AccessFDA

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