all the medications I gave Noah were for babies over 6 months, so they should be fine.
Also a good tip is to put a towel or two under one end of their mattress, so they are on a slight tilt, it helps them sleep at night, as it helps prevent the snot and junk sitting on their chest and helps it to drain away.
I really recomend the plug in inhaler things, that you just switch on in a plu socket over night and it realeases menthol stuff to help them breath, stops them lying directly on pungent drops on their bedding.