Sertraline vs Fluoxetine: what is the difference?

How they differ

Both are SSRIs, both block the serotonin transporter, and the practical difference between them is how long they stay. Fluoxetine carries a trifluoromethyl group and produces an active metabolite, norfluoxetine, that persists for a week or more, so its level falls very slowly when it stops. Sertraline carries two chlorines on a naphthalene core instead and clears in a day or two. That difference shapes how each behaves at the edges: fluoxetine is the more forgiving of a missed dose and the harder to stop cleanly, sertraline the reverse. Fluoxetine was the first SSRI to reach the market, in 1987 as Prozac, and sertraline followed as Zoloft and is now among the most prescribed medicines in the world.

Side by side

Common questions

What is the difference between Sertraline and Fluoxetine?

Both are SSRIs, both block the serotonin transporter, and the practical difference between them is how long they stay. Fluoxetine carries a trifluoromethyl group and produces an active metabolite, norfluoxetine, that persists for a week or more, so its level falls very slowly when it stops. Sertraline carries two chlorines on a naphthalene core instead and clears in a day or two.

Is Sertraline bigger than Fluoxetine?

Fluoxetine is the heavier molecule, 309.33 g/mol against 306.2 g/mol for Sertraline. Sertraline is C17H17Cl2N and Fluoxetine is C17H18F3NO.