Keep Your Kidneys Healthy in Summer Weather

Chronic Kidney Disease and Dehydration Risk:

A Practical Guide for Patients and Carers

As summer approaches in the UK, warmer weather increases the risk of dehydration. This is especially important for people living with chronic kidney disease, also known as CKD.

Hot weather can be challenging for people with CKD, but most dehydration related problems can be prevented. Simple advice about drinking enough fluids, understanding when to pause certain medicines, and knowing when to seek help can greatly reduce the risk of kidney injury.

This time of year is a good opportunity to remind patients how to stay safe, look after their kidneys, and use their medicines properly. Primary care teams play a key role in supporting patients through the summer months, and medication reviews remain an important part of safer care.

What is CKD?

Chronic kidney disease, or CKD, is a common long-term condition that affects how well the kidneys work. In the UK, it is estimated that around 1 in 10 adults has some degree of CKD, although many people are unaware of it. Early stages often have no obvious symptoms and are usually picked up through routine blood or urine tests, especially in people with diabetes, high blood pressure or heart disease.

Over time, if CKD is not well managed, kidney function can gradually worsen. This may lead to a build‑up of waste products and fluid in the body. People with CKD are at higher risk of complications such as raised blood pressure, anaemia, weak bones, fluid retention and heart disease. In more advanced stages, some people may eventually need dialysis or a kidney transplant.

Any degree of dehydration can cause problems for people with CKD. When the body does not have enough fluid, the kidneys can struggle to work properly. This can lead to a sudden worsening of kidney function, changes in salt levels in the blood, and side effects from medicines. Clear advice and simple precautions during the summer months can make a big difference to patient safety.

Why Patients with CKD Are at Higher Risk

Dehydration happens when the body loses more fluid than it takes in. In warm weather, this can happen more easily due to:

• sweating more than usual
• eating and drinking less
• illnesses such as vomiting, diarrhoea or infections

Healthy kidneys can usually cope with changes in fluid levels. In CKD, the kidneys are less able to adjust, so even a short period of dehydration can cause harm (precipitate AKI – acute kidney injury). The risk is further compounded by the widespread use of medications that affect renal perfusion or fluid balance.

Drugs commonly prescribed for conditions such as hypertension, diabetes, heart failure and cardiovascular disease may reduce renal blood flow, promote fluid loss, or accumulate during dehydration, increasing the likelihood of adverse effects.

Many people with CKD also take medicines for conditions such as high blood pressure, diabetes, heart failure or heart disease. Some of these medicines can affect fluid balance or blood flow to the kidneys, which increases the risk during hot weather or illness.

Staying hydrated: Simple Advice with Significant Impact

Maintaining adequate hydration is a cornerstone of AKI prevention. Patients should be encouraged to:

• Drink fluids regularly throughout the day, not just when thirsty.
• Increase intake during hot weather, physical exertion, or illness.
• Avoid excessive alcohol and caffeine.
• Stay cool and avoid prolonged sun exposure.
• Monitor urine colour (dark urine often indicates dehydration).

These simple steps can help reduce the risk of kidney problems and are worth discussing during routine reviews or long-term condition appointments.

The good news is that for many people, CKD progresses slowly. With regular monitoring, healthy lifestyle choices and the right medicines, it is often possible to slow progression, reduce complications and maintain a good quality of life for many years.

Sick Day Rules: A Key Summer Safety Message

One of the most important clinical interventions during summer is reinforcing “sick day rules”. These are safety‑netting instructions for patients at increased risk of AKI, advising temporary suspension of certain medications during acute illness associated with dehydration (e.g. vomiting, diarrhoea or fever).

The aim is to prevent further reduction in kidney perfusion and avoid harmful drug accumulation.

SADMAN – Medicines to Consider Pausing During Acute Illness

It should be recommended that patients temporarily stop these medicines if they cannot maintain normal fluid intake or are experiencing significant fluid loss. Once they are eating and drinking normally for 24-48 hours, treatment can usually be restarted at the usual dose.

Clear guidance is essential, as inappropriate cessation or delayed restarting may result in destabilisation of chronic conditions such as heart failure, hypertension or diabetes.

Important Medicines That Should NOT Be Stopped

It is equally important to clarify what should not be stopped:

• Insulin – should usually be continued with closer glucose monitoring.
• Steroids – must not be abruptly discontinued.
• Essential cardiovascular medicines – unless specifically advised.

Patients should also be reminded to avoid over‑the‑counter NSAIDs, particularly during hot weather or periods of illness, as these can significantly worsen renal function.

The Role of Medication Reviews in Primary Care

From a PCN and GP practice perspective, summer medication reviews offer a valuable opportunity to:

• Identify patients with CKD, heart failure or diabetes at higher AKI risk.
• Review nephrotoxic and volume‑sensitive medicines.
• Give personalised sick day advice.
• Reinforce hydration strategies.
• Supply written patient information where possible.

As a clinical pharmacist, incorporating structured education into routine reviews helps improve patient understanding, confidence in self‑management, and ultimately reduces avoidable hospital admissions related to AKI.

Conclusion

Warmer weather can present additional challenges for people living with chronic kidney disease, but most dehydration‑related problems can be prevented. Taking simple steps such as drinking fluids regularly, staying cool, and understanding when certain medicines may need to be paused during illness can greatly reduce the risk of kidney injury.

Primary care teams play a vital role in supporting patients during the summer months. Through regular medication reviews and clear, practical advice, healthcare professionals can help patients manage their condition safely, reduce complications, and support their health and wellbeing throughout the warmer seasons.

References

• Kidney Care UK. Stay safe in heat and sun
  https://kidneycareuk.org/kidney-disease-information/living-with-kidney-disease/stay-safe-in-heat-and-sun/
• Think Kidneys. Sick Day Guidance in Patients at Risk of Acute Kidney Injury (2018)
• Nottinghamshire Area Prescribing Committee. Sick Day Rules (SADMAN guidance)
• London Kidney Network. Sick Day Rules – Patient Guidance (2024)
• National Institute for Health and Care Excellence. Chronic kidney disease: assessment and management (NG203)
• NHS England. Acute Kidney Injury resources