Is it safe to take 100mg of zoloft together with 50mg pristiq (desvenlafaxine) once daily?

Should be safe: Well, the answer should be yes in that they work differently. One acts on serotonin levels in your brain after about a month and the other is an analgesic to treat pain. Depending on your body weight there should not be a major concern about respiratory depression, so it should be safe.

Yes.. But: Combining the 2 medications at the dose you mention should be safe but not necessary. Both medications are related (zoloft is an ssri and Pristiq (desvenlafaxine) is an snri). They both work on serotonin but Pristiq (desvenlafaxine) also works on norepinephrine. Unless you are planning to eventually switch and this is part of that plan, it may be better to first maximize the dose of one. Zoloft can be safely increased to 200mg.

MEDICATION: Best to discuss medication with your Psychiatrist. If uncomfortable with your Dr. consult another for a second opinion. Have a physical exam by a Dr. to determine if you have a physical illness. Consult with a Clinical Psychologist for psychotherapy with ZOOM sessions. Fears and anxiety could be heightened due to the Covid-19 pandemic. Stay safe & hopeful to elevate your immune system.