You can recover all your receipted medical expenses ie doctors' fees, prescriptions, physio expenses, nursing home, outpatients etc. less the first €250 (I think ) for a joint or family return.
This is done at the end of the current tax year and you will be able to claim at your top rate of tax, probably 42% when you send in the Med1 form along with your normal tax return.
You may be able to recover some GP costs depending on your health plan from VHI, BUPA etc.
Any shortfall is claimable against tax.