My son has a really bad post nasal drip cough. i gave him a celestamine tablet at 4pm and it is so bad it is causing him to vomit. what else can i try and when can i give it to him?

Doctor can examine: New nose, throat, and cough symptoms can be from a strep throat infection (antibiotics are needed), a cold (more likely), or from some other cause such as asthma, allergies, irritants. Usually, a person sees the doctor if the symptoms are bothersome, recurrent, or don't go away quickly. Viral infections should resolve without antibiotics. Some coughs are asthma symptoms and need inhalers.