From one prescription to five: the medication trap patients in Spain need to know

How many times have you gone to the doctor and left with several boxes of medication, one to treat the original problem, and another because you were told, “If you get this symptom, take this”? For older people taking several medicines every day, that extra prescription could sometimes be treating a side effect of another drug rather than a new illness.

New research has identified 24 potentially harmful prescribing cascades that could leave older adults taking additional medicines they may not have needed in the first place. For British and other international residents living in Spain, the findings are a reminder to look at the whole medication list when a new symptom appears, rather than assuming every new problem needs another prescription. 

When one medicine leads to another

A prescribing cascade happens when a side effect from one medication is mistaken for a new medical condition. Instead of stopping, changing or reviewing the first medicine, another drug is prescribed to deal with the new symptom. That medicine can then produce another side effect, potentially leading to yet another prescription. The result can be a growing list of medicines without the connection between them being recognised.

The new study, published in the BMJ, examined prescription data covering 2,297,942 community-dwelling adults aged 66 and over in Ontario. Researchers started with 65 potentially inappropriate prescribing cascades previously identified by an international panel of experts, then assessed how frequently the medicines were prescribed and how closely the prescriptions followed one another. Twenty-four met all three criteria used to identify the highest-priority cascades. 

Some of the combinations may look completely unrelated

One of the problems is that the original medicine and the later prescription can appear to have nothing to do with each other. Among the cascades identified as having the highest incidence was iron supplements followed by laxatives, occurring in 11.9 per cent of the relevant prescribing sequences studied. Another involved cholesterol-lowering statins followed by pain medication, while another involved cholinesterase inhibitors followed by sleep medication. 

The researchers also found particularly strong temporal associations between some medicines and subsequent prescriptions. These included corticosteroids followed by antipsychotic medication, laxatives followed by anti-diarrhoeal drugs, and cholinesterase inhibitors followed by anti-nausea medication. 

That does not mean these combinations are always wrong. Some prescribing cascades are deliberate and medically appropriate, particularly where a known side effect is being prevented or treated. The concern is when a drug-related symptom is mistaken for a separate condition and another medicine is added unnecessarily.

When in Spain…

Spain is renowned for not going easy on prescription medication, I for one have come out of consultations with at least 4-5 boxes of medicine just for an allergic reaction or muscle damage. For expats, keeping track of all those medicines can become even more complicated. You may have one prescription from your Spanish GP, another from a private specialist, and medicines that you regularly take from the UK or another country. Add over-the-counter painkillers, antihistamines or supplements and it becomes surprisingly easy for one doctor not to have the complete picture.

That is why it is important to tell every doctor or pharmacist everything you are currently taking, including medicines prescribed by another doctor and products you have brought with you from home. This becomes particularly important if you move between Spain’s public and private healthcare systems, where different doctors may not have access to the same prescribing records.

For those who are not fluent in Spanish, explaining a long medication history can also be difficult, particularly when discussing side effects or explaining when a symptom first appeared. Keeping a current written list of your medicines, their doses and what each one is for can make those conversations much easier, and could help a doctor spot when a new symptom might actually be linked to something you are already taking.

The warning is particularly important for older adults

Older people are more likely to live with several chronic conditions and therefore take multiple medicines at the same time. That increases the possibility that a new symptom will be attributed to another illness rather than a medication side effect. 

The researchers say conversations between patients and healthcare professionals can miss the connection between the first medicine, its side effect and the later prescription. They argue that doctors need to consider why every medication was started and whether it is still necessary when another drug is being considered. 

What should you do if you take several medicines?

Do not stop prescribed medication without speaking to a healthcare professional. Instead, if you develop a new symptom after starting or changing a medicine, ask whether it could be a side effect before simply adding another treatment. Keep an updated list of everything you take and show it to your doctor or pharmacist, including prescription medicines, over-the-counter products and supplements. If you have accumulated several prescriptions over the years, it is also reasonable to ask your doctor or pharmacist to review the complete list with you.

The researchers say better medication reviews and clinical systems that can flag possible prescribing cascades could help prevent unnecessary treatment and reduce medication-related harm.  For anyone living in Spain who has found their medication cupboard gradually filling with more and more boxes, the research offers a simple question worth asking at your next appointment: Could this new medicine be treating a side effect from the last one?