Many people rely on popular over-the-counter (OTC) medicines to treat their symptoms. However, some OTC medicines can raise your blood pressure or keep your prescription blood pressure medicines from working effectively. Decongestants, such as those that contain pseudoephedrine, oxymetazoline, or phenylephrine can raise your blood pressure significantly. Some OTC medications are high in sodium, which can also be harmful because a person with high blood pressure shouldn’t consume more than 1,500 mg. of sodium per day and one dose of some OTC medicines can contain more than that. Talk to your doctor or pharmacist before you take any new OTC medicines and remember to read the labels!