Is it safe to take zoloft (sertraline) with four other medications: doxycycline, rifampin, zithromax, and malarone?

Avoid unless your: doctor checked an EKG. Some of these medications in particular can cause prolongation of the QT interval (basically slowing heart conduction) and should be taken with caution under the guidance of your primary care physician.

Interactions: Rifampin and Doxycyline decrease your Malarone (atovaquone and proguanil). Please see your doctor

Probably: There is an interaction between Doxycycline and Rifampin (the rifampin may decreased the levels of doxycycline), Rifampin can also decrease the efficacy of malarone. I have not read any interactions with zoloft (sertraline) and the other medications however.