Switching From Zoloft (Sertraline) To Prozac (Fluoxetine)
In our latest question and answer, the pharmacist discusses switching from Zoloft (sertraline) to Prozac (fluoxetine).
I was just reading the article on switching from one antidepressant to another. My doctor is trying to wean me off Zoloft (sertraline) but instead of taking me slowly down, she switched me to Prozac at a lower dose. I don't understand why she did that. Why didn't she just lower the sertraline little by little to wean me off of it? Do you know why that would be? My primary care physician is the one doing all this. Its her plan to wean me off sertraline. This is really messing with my head. Sertraline was 100mg now I'm on Prozac 20 mg. Can you help so I can tell her what I would rather do?
There is no single recommended way to switch antidepressants, and there are a variety of methods that can utilized.
Before we discuss the two most common methods for switching from one SSRI (selective serotonin re-uptake inhibitor) to another, I want to point out that many patients do find that switching between different drugs in the same class (from Zoloft to Prozac in this example) can be effective. Studies have shown that most individuals are equally as likely to respond to another drug in the same class as switching to another class.
Some practitioners recommend a "cross-taper" method, which is most likely what you read in one of our other articles. With a cross-taper method, one SSRI is slowly decreased, while at the same time, starting at a low dose and gradually increasing the new SSRI.
Some sources recommend a "cross-taper" when switching between different classes of antidepressants, to avoid withdrawal symptoms and symptom re-occurrence. However, the direct switch method is used just as often, if not more so, when going from one SSRI to another SSRI since we aren't as concerned with withdrawal effects due to the same mechanism of action.
Direct Switch On SSRIs
When switching between agents in the same class of medication, such as from Zoloft (sertraline) to Prozac (fluoxetine), a direct switch is commonly utilized, which is what your doctor is doing, and is supported by multiple studies. A direct switch is done by:
- Stop the SSRI you are currently taking (Zoloft in your case).
- Start the new SSRI at a low dose (typically Prozac 20 mg every other day or every day).
If were taking a high dose of the Zoloft (>100 mg), it may be prudent to taper to a lower dose before starting the new agent to avoid increasing your risk of serotonin syndrome. However, this is can be mitigated as well by starting your new SSRI on a low dose, as your practitioner has done.
The only time a direct switch from one SSRI to another isn't recommended is if you are initially taking Prozac. Prozac has a very long half-life and after discontinuing, can last in the body for an extended period of time (weeks for some individuals). Typically, a seven-day "washout" period is advised, meaning to stop Prozac, wait 7 days, and then start the new SSRI.
As stated at the beginning, there is no single right or wrong way to switch SSRIs and the method your doctor recommends will be based on your personal medical history and their professional experience, knowledge and judgement. If you are concerned with the method being used to switch you from Zoloft to Prozac, be sure to speak with them to come up with an appropriate treatment plan.