As with any medication, an allergic reaction may be experienced by some patients. This will need to be addressed with the appropriate medical personnel at once. Symptoms of an allergic reaction may include difficulty breathing, hives, or swelling in the facial region. In addition, the following mild side effects may be experienced by users: itchiness, coughing, nausea, impotence, dizziness, insomnia, vomiting, or a lowering of the patient's sex drive. Serious side effects that can warrant professional intervention include abnormal bruising or bleeding, weakness, abnormal heart rate, rapid changes in weight, chest pains, or jaundice.