Many medications can not be purchased without a prescription either from a Private doctor or from your Spanish National Health service GP.

In Spain National health prescriptions are partly paid for by the patient. (With the exception of low income Pensioners whose prescriptions are free)

A co-payment system of contributing towards the cost of prescriptions was introduced in July 2012. Most people, including UK pensioners, will be required to pay a percentage of the cost of their prescription medication. Co-payment will be handled by each autonomous community, so processes may differ slightly between regions.
The amount each person pays will depend on annual income (proved by annual tax declaration) and individual situation. The table below provides a basic overview of what residents will be expected to contribute.
Various treatments are not available by National Health prescription in Spain, meaning these will now have to be paid for in full. Speak with your pharmacist for further information and to discuss all options available to you.

Annual income Social situation % of contribution Capped at:
Less than €18,000 Working Age 40% No capping
State Pensioner and Patients with cronic illnessesses * (see conditions below) 10% €8/month
Between €18,000 and €100,000 Working Age 50% No capping
State Pensioner 10% €18/month
Over €100,000 Working Age 60% No capping
State Pensioner and Patients with cronic illnessesses 60% €60/month

New for 2019 Lower income Pensioners in the Canary Islands

A decree was published in the Official Bulletin of the Canary Islands (BOC) on the 16 May 2019 guaranteeing free medication for all Social Security pensioners with total incomes below 18,000 euros per year.

This measure, which will take effect from the 17th May 2019 will benefit 292,458 people, 70% of the total number of Canarian pensioners.
The measure, which will involve an investment of more than 14 million euros, approved the regulatory basis for granting subsidies to Social Security pensioners and their beneficiaries.
The subsidies  will be applied automatically, without the pensioners having to apply for them.