Many people think they are allergic to a medicine when they are really experiencing a side effect.
Common side effects include symptoms such as drowsiness, nausea, diarrhea or impaired sexual function. These symptoms often diminish over time or if the doctor reduces the dose of the medicine. However, some side effects may be too severe to tolerate. Tell your doctor if you are having symptoms that you think may be caused by your medicine. True allergies to medicines result in symptoms such as skin rashes or difficulty breathing.