PREMARIN side effects, that may go away during treatment, include dizziness, lightheadedness, headache, stomach upset, bloating, nausea, weight changes, increased/decreased interest in sex, or breast tenderness. If PREMARIN side effects continue or are bothersome, check with your doctor. CONTACT YOUR DOCTOR IMMEDIATELY if you experience PREMARIN side effects like mental/mood changes (e.g., severe depression), calf/pain swelling, sudden severe headache, chest pain, trouble breathing, one-sided weakness, slurred speech, vision changes (e.g., change in contact lens fit, loss of vision), breast lumps, swelling of hands/feet, changes in vaginal bleeding (e.g., spotting, breakthrough bleeding, or prolonged bleeding), unusual vaginal discharge/itching/odor, or yellowing of the eyes/skin. PREMARIN side effects are unlikely, but seek immediate medical attention if PREMARIN side effects occur. Symptoms of PREMARIN side effects include rash, itching, swelling, severe dizziness, or trouble breathing. If you notice other PREMARIN side effects not listed above, contact your doctor, nurse, or pharmacist.