Hutch asked
I have been taking 20mg of fluoxetine for a long time, but that dose seems to be not as effective as my anxiety/depression came back. Doctor increased dose to 30mgs fluoxetine one a day and had side effects within 14 days. By 8 weeks I've been OK and the increase seems to be working. However, the 30mg capsules are no longer available. My doctor has started me on 40mgs fluoxetine one day and 20mgs fluoxetine the next day which he said is still 30mgs of fluoxetine. My question is will I get side effects with this change?
Answer
It's possible you may have a slight increase in side effects after taking a 40 mg dose of fluoxetine, but they should level off with consistent dosing. SSRIs (selective serotonin reuptake inhibitors) are well known to cause dose dependent side effects, including:
- Gastrointestinal (e.g. nausea, diarrhea)
- Activation/insomnia (e.g. exacerbation of restlessness, agitation, and sleep disturbances)
- Sexual dysfunction
- Neurologic effects (e.g. exacerbate both migraine headaches and tension headaches)
- Weight fluctuations
Side effects, if they do occur, often show quickly after starting a medication or a dose is changed. They do tend to subside the longer you take the medication. If they are particularly troublesome or do not subside, a dose reduction or change in medication should be considered.
In your situation, a dose increase may bring on some side effects, such as nausea, but should hopefully go away in a few weeks. Although you are taking an average of 30mg over two days, you are still increasing your dose (40mg) on one of those days. After several doses, you should reach a steady-state, and any side effects should (hopefully) normalize.
