For those stuck here without flights and concerned about prescription renewal, the Consulate has now issued the following advice:
To obtain prescription medicine in the Canary islands as a visitor, you must telephone 012 and you will be informed where the nearest health centre is/what steps you need to take. If you are experiencing problems organising replacement medication and need medication urgently, please write to firstname.lastname@example.org and put “PLEASE CONTACT ME – MEDICATION” in the subject line.
Please note that 012 might not have an English-speaking operative available, and the line is overwhelmed in any case. Some readers have found that their local chemist is very helpful, and just taking in an old prescription, or even just a box of used medication, can work. Others have managed to get emails from UK doctors confirming the prescription. The farmacias are being very helpful to everyone right now, including state system patients who simply turn up with their health card after a telephone appointment with their doctor, and their prescription is automatically renewed.
Anyone in trouble should definitely try their chemist first, and of course in extremis, there are private doctors here who can prescribe. It won’t be the cheapest option but it will get you medication.