RP Gest 100mg Soft Gelatin Capsule is a natural female sex hormone, progesterone. It is used to treat menstrual and pregnancy-related issues that are caused due to hormonal imbalance. RP Gest 100mg Soft Gelatin Capsule is also prescribed along with estrogen as a part of hormonal replacement therapy for preventing endometrial hyperplasia (thickening of the lining of the uterus). It should be taken without food, preferably in the evening or at bedtime. It should be taken at the same time each day to get the most benefit. You should continue taking it for as long as your doctor has told you to, even if you feel well. The most common side effects include abdominal bloating, abdominal pain, dizziness, headache, depression, breast tenderness, hot flushes, vaginal discharge, joint paint, and urinary incontinence. Side effects are more common during the first few weeks and usually lessen as your body gets used to the medicine. You may also experience bleeding or spotting between your periods, consult with your doctor if it happens frequently. If you experience dizziness or tiredness, avoid driving or activity which requires mental concentration. Before taking this medicine, inform your doctor if you have, or have had, breast cancer, unusual bleeding in the vagina, or liver disease. You will probably have several tests both before and during treatment to check your womb. Also, tell your doctor what other medicines you are taking as some may affect, or be affected by, this medicine.