Prednisone is a prescription medicine intended for the treatment of such conditions as asthma, arthritis, allergies, skin conditions and multiple sclerosis. Some of the effects Prednisone may have on you include an increase in blood pressure, retention of salt and water in your body and loss of potassium. Make sure you discuss your diet with your health care provider to avoid such consequences. Receiving a live vaccine during the whole period of treatment is not recommended as you are likely to fall ill since your immune system will not be able to fight the vaccine.