If your symptoms do not improve or if they worsen, talk to your doctor. Chlorpheniramine is an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body. Dextromethorphan is a cough suppressant. It suppresses an area in your brain that causes you to cough.
Phenylephrine is a decongestant.
A very dangerous drug interaction could occur, leading to serious side effects. Do not give this medication without first talking to your doctor if you are pregnant. This medicine passes into breast milk and may affect a nursing baby. Do not take this medication without first talking to your doctor if you are breast-feeding a baby. You may require a lower dose of this medication.