You will need to discuss with the doctor or specialist who prescribes your medication how you can get an ongoing supply. This will vary according to the country in which you live and the local services available, but usually arrangements are made for repeat prescriptions to be available at a pharmacy which is convenient for you.
Your doctor will also be able to tell you how many weeks supply you can have in advance, again this varies from country to country so you will need to ask about this.
