Not taking Prozac consistently — Effects?

Dear Alice,

Are there any side effects with Prozac if it is not taken on a regular basis?

Dear Reader,

Spontaneity may be the spice of life, but routine is key when taking antidepressants such as Prozac (generic name: fluoxetine). Fluoxetine belongs to a family of medications called selective serotonin reuptake inhibitors (SSRI). It's not clear from your question what you would mean by an irregular basis, but these medications work best when they're taken as prescribed by a health care provider. Skipping doses or taking fluoxetine without a prescription will have different effects, potentially harmful, for each individual.

For those with a prescription, the most benefit is gained when they’re taken on a regular basis as prescribed. Antidepressants, such as fluoxetine, work by altering the balance of chemicals in the brain, so deviating from the medication schedule can upset this balance. If a dose is missed, it’s generally not recommended to double up on doses. Simply skipping the missed dose and resuming the scheduled doses is recommended. If it’s hard to remember to take medication as prescribed, setting an alarm or including it as part of a morning or evening routine could be a useful tool to prevent skipped doses. If fluoxetine hasn’t been taken for several weeks, withdrawal symptoms such as headaches, nausea, irritability, or insomnia may occur. The Go Ask Alice! Q&A SSRI withdrawal speaks more about the side effects that a person could experience if they stop taking it suddenly. 

For those who haven’t been prescribed fluoxetine, popping the pills occasionally can be harmful to the body. Unlike over-the-counter pain relievers and cold medicine, antidepressants need to be taken over a period of time (several weeks at the minimum) to work effectively. Taking the pills occasionally aren’t likely to provide any mental health benefits, and there is a risk of side effects or unintended overdose. If too much is taken, medical attention is necessary immediately for those who experience seizures, a speedy, slow, or irregular heart rate, nausea and vomiting, or uncontrollable trembling, as all of these may be signs of an overdose. 

If you're taking fluoxetine and feel concerned about any side effects, connecting with your health care provider or mental health professional before changing how you take your meds can help you make a more informed decision. In addition, if you're feeling blue and aren’t currently taking any medications, it’s wise to talk with a health care provider before trying out fluoxetine or other antidepressants that aren’t prescribed for you. Antidepressants work best when taken as prescribed, so if you're on fluoxetine, routine is the name of the game.

Last updated Jul 03, 2020
Originally published Oct 09, 2009

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