Doctor has changed medication from pristiq (desvenlafaxine) to cymbalta , what is the main difference please and am now more likely to gain weight please. thank you ?

Cymbalta, Pristiq (desvenlafaxine): Both medications are dual action antidepressants. At high dose Pristiq (desvenlafaxine) may be a triple action antidepressant. Short term studies show little weight gain in both meds. However individuals vary with regard to side effects as well as their response to a particular antidepressant. Long term studies indicate that similar drugs can cause significant weight gain in susceptible individuals.

If you are not comfortable or unsure about the medication your Doctor prescribed then it is advisable to get a second opinion from a Psychiatrist after you have had a complete physical exam by your Primary Care Physician to rule out any underlying illness. A Clinical Psychologist can also help you with psychotherapy.