Fluoxetine: Difference between revisions
| [checked revision] | [checked revision] |
MDElliottMD (talk | contribs) No edit summary |
MDElliottMD (talk | contribs) No edit summary |
||
| Line 12: | Line 12: | ||
| halflife = 1–4 days (7–15 days for norfluoxetine) | | halflife = 1–4 days (7–15 days for norfluoxetine) | ||
| bioavailability = 70–90% (oral) | | bioavailability = 70–90% (oral) | ||
| pregnancy = Category C | | pregnancy = Category C<ref>https://www.ncbi.nlm.nih.gov/books/NBK501186/</ref> | ||
<ref>https://www.ncbi.nlm.nih.gov/books/NBK501186/</ref> | |||
| legal = Rx-only | | legal = Rx-only | ||
| mechanism = [https://pmc.ncbi.nlm.nih.gov/articles/PMC9666396/ TrkB/BDNF] <vote slug="ssri-claim">Fluoxetine is a selective serotonin reuptake inhibitor.</vote> | | mechanism = [https://pmc.ncbi.nlm.nih.gov/articles/PMC9666396/ TrkB/BDNF] <vote slug="ssri-claim">Fluoxetine is a selective serotonin reuptake inhibitor.</vote> | ||
| Line 48: | Line 47: | ||
</anecdote> | </anecdote> | ||
| seealso = [[Sertraline]], [[Duloxetine]] | | seealso = [[Sertraline]], [[Duloxetine]] | ||
| references = | | references = <references/> | ||
}} | }} | ||
Revision as of 02:17, 13 May 2026
SSRI, Anxiolytic, Antidepressant
Fluoxetine
Prozac
Fluoxetine was the first of a long line of SSRIs. It is notable for its extremely long half-life and relative lack of withdrawal syndrome. It can also be useful in helping taper and discontinue other SxRI medicines.
None required
Sertraline, Duloxetine
Experience
No personal reports yet
1 provider report · avg efficacy 40.0/100 · avg side-effect burden 40.0/100 · 150 patients managed total
Log in to add your own experience.
Problems
Anxiety disorders broadly (including panic, social anxiety, OCD), depressive disorders, potentially PTSD
+ Add a problemTitration strategies
Standard adult or child+1
Start no higher than 10 mg for the first dose. May increase by 10 mg every 2–12 weeks, or remain at 10 mg if the response is adequate, up to a typical starting maximum of 40 mg. Absolute max: 80 mg.
OCD+1
Start at 10 mg daily; increase by 10–20 mg every 2–6 weeks, up to 80 mg. OCD typically requires elevated doses (60–80 mg).
Effects
Anxiolysis no reports yet ~33% +67.0 (n=1)
Classically starting at 3–4 weeks and improving for another 8–12.
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Delayed orgasm/ejaculation 0% — (n=3) ~80% +38.0 (n=1)
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Mood enhancement no reports yet ~5% +67.0 (n=1)
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Nausea no reports yet ~5% -33.0 (n=1)
Common, often improves over 1–2 weeks.
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Decreased libido no reports yet ~33% -100.0 (n=1)
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Temporary erectile dysfunction no reports yet ~20% -67.0 (n=1)
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Persistent Sexual Dysfunction no reports yet ~0% -100.0 (n=1)
Persistent sexual dysfunction, historically associated with SSRIs
Did you experience this?
How often have you seen this?
How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Pharmacokinetics
Absorption
70-90% Oral bioavailabilityDistribution
Fluoxetine has plasma protein binding of approximately 94.5%, bound to albumin and alpha-1 glycoprotein. Fluoxetine readily crosses the blood-brain barrier, with a brain-to-plasma ratio of 2.6:1 in humans. The volume of distribution (Vd) of fluoxetine and its metabolite ranges between 20 to 42 L/kg. Some studies report that fluoxetine has the maximum volume of distribution (Vd) of any SSRI (between 14 and 100 L/kg).Metabolism
Fluoxetine's active metabolite is norfluoxetine, produced when the cytochrome P450 enzyme (CYP2D6) acts on it. Prescribers must remember that fluoxetine has several drug-drug interactions due to its metabolism through the CYP2D6 isoenzyme. Additionally, norfluoxetine can have an inhibitory effect on CYP3A4. Fluoxetine has a half-life of 2 to 4 days, and its active metabolite norfluoxetine has a half-life of 7 to 9 days. Approximately 7% of individuals definitively exhibit poor metabolism of fluoxetine due to reduced activity of CYP2D6.Monitoring
Relevant anecdote
⚕️ Provider 0
Fluoxetine is great for getting off other SxRIs! Especially venlafaxine and duloxetine.
Relevant Literature
No literature entries yet.
Log in to submit relevant literature.
See also
References
Pharmacy
Starting dose
10 mg
Preparations
10 mg, 20 mg, 40 mg caps
Common uses
Common uses
- Depressive disorders1.0n=1
- Anxiety disorders broadly4.0n=2
- Panic disorder1.3n=2
- Social anxiety disorder1.0n=1
- Obsessive-compulsive disorder3.0n=1
Structure
Classification(s)
Classes
SSRI, Anxiolytic, Antidepressant