Phenylephrine chlorpheniramine is a combination of an antihistamine and a decongestant. It is used to treat symptoms of allergy, cold, or sinus inflammation. Plus, this combination will help relieve runny nose, sneezing, and congestion in the nose. You should tell your health-care provider before using Phenylephrine chlorpheniramine if you have asthma, diabetes, glaucoma, high blood pressure or heart disease, or if you have prostate trouble or thyroid disease. You also need to tell them if you are pregnant or trying to get pregnant, or if you are breastfeeding. In fact, it is still not known whether chlorpheniramine and phenylephrine will harm an unborn baby. So, you must not use this medicine without your doctor's advice if you are pregnant. Besides, it is not known whether this combination medicine passes into breast milk, or if it could harm a nursing baby. As a matter of fact, antihistamines and decongestants may also slow breast milk production. Therefore, the safest thing to do is to consult your doctor before using Phenylephrine chlorpheniramine. You must stop using this medicine and call your doctor at once if you experience the following side effects: chest pain, rapid pulse, confusion, hallucinations, tremor, seizure, little or no urinating, easy bruising or bleeding.