What are the side effects of nelfinavir mesylate?

Nelfinavir mesylate can cause a variety of side effects. If you have trouble breathing, swelling in the face, lips, tongue, or neck, or hives, you may be allergic to the medication and should get emergency medical assistance. Call your doctor right away if you experience other serious side effects such as trouble breathing or fever. Call your doctor if any of the following side effects are persistent or bothersome: diarrhea; weight gain in your midsection and loss in the arms, legs, or face; increased urination, hunger, or thirst; nausea or vomiting; gas or stomach pain; unusual fatigue or weakness; or skin rash.