Is it dangerous to take zoloft (sertraline) if you are allergic to sulfa drugs?

No : Sertraline (zoloft) is not a sulfa drug, and I am not aware any allergic cross-reactivity between the two.

It Is Safe: Zoloft (sertraline) does not contain any sulfa in its tablets. There are generic versions of zoloft and they are also sulfa free. Zoloft is a serotonin reuptake inhibitor medication that has been approved by the fda for the following conditions: major depressive disorder, obsessive compulsive disorder, panic disorder, social phobia, post-traumatic stress disorder, premenstual dysphoric disorder.