Side effects of chlorpheniramine include uneven heart rate, convulsions, abnormal weakness and shortness of breath. Dizziness, dry throat, nervousness, blurred vision and constipation are also side effects of chlorpheniramine. A patient who experiences these symptoms should immediately stop using chlorpheniramine and consult a doctor, according to Everyday Health.
Patients with a colostomy, liver ailment, high blood pressure and urinating problems should inform a doctor before taking chlorpheniramine. Additionally people with epilepsy, an adrenal gland tumor, a recent heart attack, emphysema and kidney illness should also tell a doctor before taking chlorpheniramine. A person who has an asthma attack, an enlarged prostate, a stomach blockage and narrow glaucoma should avoid taking chlorpheniramine. Pregnant or breastfeeding should consult a doctor before using chlorpheniramine. Chlorpheniramine is an antihistamine, so it slows down production of breast milk, says Everyday Health.
Chlorpheniramine relieves rashes, watery eyes, itchy nose, itchy throat and sneezing that result from hay fever, allergies and common colds. It works by blocking histamines, which the body produces in an allergic reaction. It also blocks acetylcholine production, drying up body fluids. Chlorpheniramine affects laboratory tests, such as the skin allergy test. It reacts with Parkinson's medication, such benztropine and trihexyphenidyl. It also reacts with antihistamines used on the skin, such as diphenhydramine cream, according to WebMD.