Is it safe to give a 2month old dimetapp?

I never would. A 2 mo is dependent on their nasal passages to breathe.The don't routinely use their open mouth to augment breathing until 4-6m. Dimetapp and similar drugs (once prescription meds) work by drying secretions,thickening the buggers, making any drainage in a babies nose thicker. Useing this is one way to make it harder for them to breathe. Nasal saline washout is the best Rx for a 2 mo.
Dimetapp. No. Otc cold medications have been shown to be useless in treating colds in children less than 6 years old. In addition, side effects can make their condition worse and cause diagnostic problems.