During heatwaves, vulnerable patients may need to temporarily skip certain medicines

Vulnerable patients on certain medications face a higher risk of hospital admission due to dehydration during heatwaves. During such hot spells, but also when patients have a fever, diarrhea, or are vomiting, it’s safer to temporarily lower the dose or stop taking these medications entirely. Yet this often does not happen, either because of a lack of awareness or insufficient attention in healthcare practice. PhD candidate Tristan Coppes, who defends his dissertation today, has taken concrete steps to improve both understanding and practice.

Due to climate change, heatwaves are becoming more frequent. At the same time, the population in the Netherlands is aging. The elderly, particularly those with kidney disease or heart problems, are most at risk of being hospitalized with dehydration symptoms.

Certain medications that are normally safe, can become harmful when people are dehydrated. This includes diabetes medications, blood pressure-lowering drugs, and NSAID painkillers like diclofenac and ibuprofen. These medications reduce the body’s ability to handle dehydration and increase the risk of (further) kidney damage.

These medications have a long-term effect, so it’s safe to pause them temporarily for a few days.

“An analysis of data from 75 hospital admissions for dehydration showed that all admitted patients were taking at least one of these medications,” Coppes explains. “Eighty percent were taking two or more.”

Lack of knowledge

Diuretics, commonly called “water pills”, also belong to this group of medications. “They make you urinate more, so if you’re already sweating heavily or have diarrhea, it makes sense to reduce or stop taking them,” explains Coppes. “But this doesn’t always happen in practice.”

From interviews conducted by Coppes it became clear that many patients and informal carers are unaware of the risks associated with medication in cases of impending dehydration. Patients often don’t adjust their medication during illness or hot weather, and they don’t always consult a healthcare professional. “These medications have a long-term effect, so it’s safe to pause them temporarily for a few days,” said Coppes, who graduated as a pharmacist from Utrecht University.

When we spoke to informal caregivers, we found they were actually very interested and wanted to know what to do when their family member was ill.

Updated guidelines

Besides patients, Coppes also interviewed healthcare professionals. Doctors and pharmacists acknowledged the importance of adjusting medication on high-risk days but admitted this still does not receive enough attention in practice.

The PhD candidate therefore proactively contacted the Nederlands Huisartsen Genootschap (NHG), the organization responsible for developing treatment guidelines for GPs in the Netherlands. Based on the results of Coppes’ research, the guidelines on medication use for dehydration during periods of heat and illness were updated. “That was actually the goal I set for myself,” he says. “I know most pharmacists refer to the guidelines, but not to the medical literature. I wanted my research to make a real difference in practice.”

Information leaflets

During the interviews, GPs and pharmacists also mentioned the need for clear patient information materials. In his project, Coppes addressed this by collaborating with the Dutch Kidney Foundation to create a patient leaflet titled “Soms moet u uw medicijnen even overslaan” (Sometimes you need to skip your medication for a while). “The leaflet’s message is: contact your doctor or pharmacist in hot weather or if you’re sick, and you are showing signs of dehydration. They’ll provide the right advice,” says Coppes.

Forgotten again

The PhD candidate also developed patient information letters, an e-learning module for pharmacy and doctors’ assistants, and training materials for GPs and pharmacists. Over twelve months, twenty pharmacies and GP practices tested these materials in real-world settings. Coppes followed up with some of the patients to see how much of the information they retained. 

“We found that after two months, half of the patients had forgotten the details,” says Coppes. “This might also be due to their average age, nearly 80 years old.”

Role of informal caregivers

Patients often have been taking the same medication for years and have always been told how important it is to keep taking it. “Many of these patients are on multiple medications and sometimes don’t even know what they’re taking, or don’t feel the need to know it,” says Coppes. “But when we spoke to informal caregivers, we found they were actually very interested and wanted to know what to do when their family member was ill.”

Some pharmacies therefore invited not just the patient but also their informal caregiver to the information sessions. “They were very satisfied with this approach, as it led to more feedback than when they only spoke to the patient,” says Coppes.

Home care

Coppes points out that homecare services and district nurses also can play an important role. “When visiting patients at home, they can monitor the situation and call a doctor if needed. However, we don’t yet have a clear picture of how aware this group is of medication use during hot weather or sick days. It would be valuable to explore this further in a follow-up study.”