The good news is that the ingredients for all of these are just about the same. So once you understand what each ingredient does, how to dose it, and what side effects you can expect, you can then decide on a product based on factors such as taste, texture and which form your child will be able to take, i.e., liquid, chewables, or pill form. They may simply relieve the symptoms such as congestion, and the relief will only last about 4-6 hours depending on the product. So, learn about these drugs, and then learn how to read labels. This will enable you to make intelligent choices based on more than just the information provided by advertisements.
Antihistamines are drugs which are most effective against the symptoms of allergies.
There is a debate over how much an antihistamine really helps the nasal congestion caused by the common cold, the swelling of the inflamed linings of the nose and sinus areas. Decongestants come either topically as in nasal sprays or in liquid or pill form. You can buy them as single ingredient or more commonly in combination with one of the antihistamines listed above. After some trial and error, most parents will learn which decongestant works best for their child and produces the least side effects. Some children are more sensitive than others, and infants may be more sensitive than older children.