Remeron vs. Fluoxetine
See how Remeron and Fluoxetine compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Remeron tends to cause sedation and increased appetite, while fluoxetine is more likely to cause insomnia and reduced appetite.
Fluoxetine has FDA approval for more conditions, including OCD, bulimia, and panic disorder, while Remeron is approved only for depression.
Both carry a boxed warning for increased suicidal thoughts in young people and can cause serotonin syndrome when combined with other serotonergic drugs.
Remeron vs. Fluoxetine Drug Summary
Remeron
Remeron (mirtazapine) is a tetracyclic antidepressant approved for major depressive disorder in adults. It is taken once daily, usually at night, and tends to cause more sedation at lower doses than at higher ones. It is also used off-label for insomnia, anxiety, and appetite stimulation.
Fluoxetine
Fluoxetine is an SSRI approved for major depressive disorder, OCD, bulimia nervosa, and panic disorder in adults, and for depression and OCD in children. It is taken once daily, and its long-acting active metabolite also allows a once-weekly maintenance option. It is one of the most established and widely used antidepressants available.
Remeron vs. Fluoxetine Side Effects
Remeron
Fluoxetine
Remeron vs. Fluoxetine Dosage
Remeron
Fluoxetine
| STAGE | DOSE | WHEN |
| Starting dose | 15 mg once daily | At the start |
| Maximum dose | 45 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 |
Remeron
| STAGE | DOSE | WHEN |
| Starting dose | 15 mg once daily | At the start |
| Maximum dose | 45 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 |
Remeron vs. Fluoxetine Indications
Remeron
Remeron is FDA-approved only for major depressive disorder in adults. Off-label, prescribers sometimes use it for insomnia, anxiety, or to stimulate appetite in patients who are losing weight.
Major depressive disorder in adults
Off-label: insomnia
Off-label: anxiety disorders
Off-label: appetite or weight stimulation
Off-label: nausea in pregnancy
Fluoxetine
Fluoxetine is FDA-approved for a wider range of conditions, including depression, OCD, bulimia nervosa, and panic disorder, in both adults and children. It is also combined with olanzapine for bipolar depression and treatment-resistant depression.
Major depression in adults and children 8+
Obsessive-compulsive disorder in adults and children 7+
Bulimia nervosa in adults
Panic disorder in adults
Off-label: premenstrual dysphoric disorder
Remeron vs. Fluoxetine Pros and Cons
Remeron
Remeron's sedating profile makes it a useful option for depression with insomnia, but its strong effects on appetite and weight are a common reason patients stop taking it. It is approved only for depression, so it offers fewer treatment options than fluoxetine.
Pros
Sedating effect can improve sleep, often dosed at night
Less likely to cause sexual side effects than SSRIs
Available as an orally disintegrating tablet
Can help stimulate appetite in underweight patients
Cons
Significant weight gain and appetite increase are common
Sedation can impair daytime alertness, especially early on
Rare risk of severe neutropenia or agranulocytosis
Only FDA-approved for depression, not other conditions
Fluoxetine
Fluoxetine's long history and broad FDA approval make it a flexible choice for depression, OCD, and several other conditions. Its energizing profile can cause insomnia for some patients, in contrast to Remeron's sedating effect.
Pros
FDA-approved for OCD, bulimia, and panic disorder too
Approved for children as young as 7 for OCD, 8 for depression
Once-weekly maintenance dosing option available
Long safety track record since 1987 approval
Cons
Insomnia and nausea are common early side effects
Not sedating, so it doesn't help with sleep problems
Long half-life means interactions can persist after stopping
Not used off-label for appetite stimulation or sedation
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