Zoloft vs. Fluoxetine
See how Zoloft and Fluoxetine compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Zoloft and fluoxetine are both SSRIs, but Zoloft carries FDA approval for PTSD, social anxiety disorder, and PMDD, conditions fluoxetine's label does not cover.
Fluoxetine's long-acting metabolite allows a once-weekly maintenance option and eases missed doses, while Zoloft is taken daily and clears the body faster.
Both drugs share nausea, headache, insomnia, and diarrhea as common side effects, though fluoxetine shows a notably higher insomnia rate in trials.
Zoloft vs. Fluoxetine Drug Summary
Zoloft
Zoloft (sertraline) is a selective serotonin reuptake inhibitor (SSRI) used to treat major depressive disorder, OCD, panic disorder, PTSD, social anxiety disorder, and premenstrual dysphoric disorder. It is taken once a day, usually starting at 25 mg or 50 mg, with the dose raised as needed up to 200 mg.
Fluoxetine
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) approved for major depressive disorder, OCD, bulimia nervosa, panic disorder, and certain bipolar depression when combined with olanzapine. It starts at 10 mg to 20 mg once daily and can be raised to 80 mg a day, with a once-weekly 90 mg option for maintenance.
Zoloft vs. Fluoxetine Side Effects
Zoloft
Fluoxetine
Zoloft vs. Fluoxetine Dosage
Zoloft
Fluoxetine
| STAGE | DOSE | WHEN |
| Starting dose | 25-50 mg once daily | Week 1 |
| Maximum dose | 50-200 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 10 mg once daily | Week 1 |
| Maximum dose | 90 mg once weekly | If needed |
| Dose changes | 4 increases | Every week |
Zoloft
| STAGE | DOSE | WHEN |
| Starting dose | 25-50 mg once daily | Week 1 |
| Maximum dose | 50-200 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
Fluoxetine
| STAGE | DOSE | WHEN |
| Starting dose | 10 mg once daily | Week 1 |
| Maximum dose | 90 mg once weekly | If needed |
| Dose changes | 4 increases | Every week |
Zoloft vs. Fluoxetine Indications
Zoloft
Zoloft is FDA-approved for major depressive disorder, OCD, panic disorder, PTSD, social anxiety disorder, and premenstrual dysphoric disorder. It is one of the few SSRIs approved specifically for PTSD and social anxiety disorder.
Major depressive disorder in adults
OCD in adults and children ages 6-17
Panic disorder in adults
PTSD in adults
Social anxiety disorder and PMDD in adults
Fluoxetine
Fluoxetine is FDA-approved for major depressive disorder, OCD, bulimia nervosa, and panic disorder. It also has approval, in combination with olanzapine, for depressive episodes of bipolar I disorder and treatment-resistant depression.
Major depressive disorder in adults and kids 8-18
OCD in adults and children ages 7-17
Bulimia nervosa in adults
Panic disorder in adults
Bipolar depression, with olanzapine
Zoloft vs. Fluoxetine Pros and Cons
Zoloft
Zoloft carries FDA approval for a wider range of anxiety-related conditions, including PTSD and social anxiety disorder. It has a shorter half-life than fluoxetine, so it leaves the body faster but can cause more noticeable effects if a dose is skipped.
Pros
FDA-approved for PTSD, social anxiety disorder, and PMDD
Shorter half-life clears the body faster if a switch is needed
Long track record with well-documented dosing across many conditions
Cons
No once-weekly maintenance dosing option
Shorter half-life raises discontinuation symptom risk if stopped abruptly
Oral solution contains alcohol, so it cannot be combined with disulfiram
Fluoxetine
Fluoxetine's long-acting metabolite smooths out missed doses and offers a once-weekly maintenance option not available with sertraline. Its FDA-approved anxiety indications are narrower, but it includes a combination option for treatment-resistant and bipolar depression.
Pros
Once-weekly maintenance dosing option after initial daily use
Long half-life makes missed doses less disruptive
Only SSRI combination approved for treatment-resistant depression
Cons
Not FDA-approved for PTSD, social anxiety disorder, or PMDD
Higher reported insomnia rate in trials than sertraline
Long half-life means it takes longer to clear if side effects occur
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