I second travel insurance and it depends where in Europe. I've been to the Netherlands and I needed novorapid at the time, the pharmacist was very kind and said she'll let me buy novorapid over the counter - 80 euros for 10 novorapid cartridges, 40 euros per box. Usually you need to see the doctor to get a prescription, but in most cases I'd ask the pharmacist first, along with travel insurance, passport, any medication packaging or your prescription.