There are a few things going on:
- Will you be allowed to pass through airport security with the items as a carry-on
- Will Swiss Airline allow you on board with the items as a carry-on
- Will you be able to pass customs with the items at Ireland.
To begin things on the right foot; make sure you are carrying a current prescription (in English) for your medication. It should mention your name and the amount (quantity) of medication and the type (generic and pharmaceutical name) of the drugs and the potency or dosage.
Generally speaking, medical syringes (as long as they are properly sealed and carried in their original packaging and clearly marked) as okay to carry on board; as these are necessary for your well being.
You'll have to check with Swiss if they will allow the size of box you are talking about in the cabin (they may even have a specific place to put it); just call the airline and ask. You may be allowed to take a specific amount and the remainder to be checked into luggage. Please, inform the airline as they may have to make specific arrangements in the cargo hold for your goods.
For #3, you'll need to carry a prescription from your doctor (it should be in English) and mention the exact medicine and the amount you would need for the period.
The medicine should be sealed and clearly labeled, and ideally in its original packaging.
It must not also be a controlled substance. Some medicines (such as pain killers) are legal in some countries but are classified as controlled narcotics in others (making them illegal). Unfortunately it is upto you to figure out if your medicine qualifies as such, in which case you may not have a recourse except to get a prescription from a doctor in Ireland to have it administered to you.
The correct people to ask are:
The Department of Health
Dublin D02 VW90
Tel: +353 (0)1 6354000, LoCall 1890 20 03 11