According to PrescriptionDrugs.com, it's important to discard unused Sudafed PE products after the expiration date has passed. Sudafed PE contains the decongestant phenylphrine. BJC Healthcare explains that decongestants can be less effective when consumed after the expiration date, especially when stored in bathrooms with high humidity levels.
Sudafed PE should be stored at room temperature and kept away from moisture and heat, according to eMedicineHealth. Unused, expired Sudafed PE should be discarded as directed by a pharmacist and should never be flushed down the toilet. Individuals with medical conditions such as high blood pressure, diabetes, thyroid disorders, kidney disorders or glaucoma should consult with a physician prior to taking Sudafed PE to avoid potential side effects.