How can I book an appointment with Médis? With the Médis Guide you can search for specialty, hospital, clinic or practice and call directly to book it. You must mention you are a Médis Client when you are booking it. To use the international coverages you will need a pre-authorization from Médis to activate the Insurance. To request this pre-authorization or to know the adequate institution for you, you must send an email to firstname.lastname@example.org or call the Médis Line +351 218 458 888.