Didrex successfully suppresses the appetite in overweight patients. For most, weight management patients, Didrex is safe to use. When Didrex is used in conjunction with a proper diet and exercise regimen, it can be very effective. The body endures an adjustment period with Didrex; therefore, the following side effects may occur: irritability, upset stomach, constipation, dry mouth, sleeplessness, restlessness, or nervousness. Prior to using Didrex, a physician should be notified of a patient’s entire medical history.