Kidney function in the years after chemotherapy

Sometimes. Most people's kidneys recover well after chemotherapy, but some medicines can cause lasting changes in kidney function. Cisplatin is the medicine most often linked with long-term kidney effects, including reduced filtering ability and loss of salts such as magnesium and potassium. Ifosfamide can damage the tubes inside the kidney, leading to loss of salts, phosphate and bicarbonate, which in children can affect bone growth. High-dose methotrexate can harm the kidneys if not cleared properly, although modern care usually prevents lasting damage. Other contributors include certain targeted medicines, some antibiotics and antifungal medicines given during treatment, kidney surgery, radiotherapy to the abdomen, stem cell transplant, and repeated dehydration from vomiting or diarrhoea.

Kidney problems after treatment often cause no symptoms until they are significant, which is why checks matter for people at higher risk. Risk is greater in people who received higher total amounts of cisplatin or ifosfamide, those who had kidney disease, diabetes or high blood pressure before treatment, older adults, children, and people who had a kidney removed. Reduced kidney function may show up as abnormal blood tests, protein in the urine or high blood pressure. Occasionally, people notice swelling, tiredness, muscle cramps or changes in urination.

Monitoring usually involves periodic blood tests for kidney function and salts, urine tests for protein, and blood pressure checks, at intervals your doctors decide. If kidney function is reduced, a kidney specialist may advise on protecting remaining function. Everyday steps help: keeping blood pressure and blood sugar well controlled, drinking enough fluids, avoiding unnecessary anti-inflammatory painkillers such as ibuprofen, checking with a doctor before taking new medicines or herbal remedies, and telling any doctor who orders contrast scans about your kidney history. This page explains the general picture; your doctor can assess your kidneys.

Most kidneys recover

Lasting effects affect some people, mainly after certain medicines.

Problems are often silent

Blood, urine and blood pressure checks find changes early.

Kidneys can be protected

Blood pressure control, hydration and avoiding harmful painkillers help.

It cannot tell you whether your kidneys have been affected or how much. Blood and urine tests, interpreted by your doctor, can answer that.

It also cannot advise on medicines or supplements for kidney problems. Your doctor decides.

Low magnesium and potassium

After cisplatin, some people lose magnesium and potassium through the kidneys for a long time. Low levels can cause cramps, weakness, tiredness or heart rhythm problems. Blood tests detect this, and supplements prescribed by your doctor may be needed.

Children and kidney effects

Children who received ifosfamide or cisplatin may lose phosphate and other salts, which can affect bone growth. Regular blood and urine tests and growth monitoring are part of long-term follow-up.

Contrast scans

Dye used in some CT scans can strain kidneys. Tell the scan team about your treatment history and kidney function so they can take precautions.

Painkillers and remedies

Anti-inflammatory painkillers such as ibuprofen and diclofenac, and some herbal or traditional remedies, can harm kidneys. Ask a doctor or pharmacist before taking them.

Diet and kidneys

If kidney function is reduced, a dietitian may advise on salt, protein, potassium and fluid intake. Do not restrict foods without advice.

Future treatments

If you ever need further cancer treatment, kidney function will affect medicine choices and amounts.

Pregnancy and kidneys

Women with reduced kidney function who plan pregnancy should discuss this with their doctor beforehand.

Cisplatin and hydration

When cisplatin is given, large volumes of fluid through a drip and sometimes magnesium are used to protect the kidneys. Even with these precautions, some people have lasting changes, which is why follow-up tests are useful.

Signs of low salts

Low potassium or magnesium may cause muscle cramps, twitching, weakness, tiredness or palpitations. These symptoms should prompt a blood test.

Kidney function and ageing

Kidney function naturally declines with age, so people who had kidney-affecting treatment may notice effects more as they grow older. Regular checks help detect gradual changes.

Blood pressure goals

Your doctor will advise on blood pressure goals if your kidneys are affected, and may prescribe medicines that protect the kidneys. Home monitoring can help.

Diabetes and kidneys

High blood sugar damages kidneys over time. Good sugar control is particularly important for survivors with reduced kidney function.

Protein in the urine

Protein leaking into urine can be an early sign of kidney strain. A simple urine test detects it, and treatment can slow further damage.

Medicines to check with a pharmacist

Some antibiotics, heartburn medicines, painkillers and supplements need adjustment or avoidance with reduced kidney function. Tell your pharmacist about your kidney history.

Staying hydrated in hot weather

In hot summers, dehydration can strain kidneys. Drink enough fluids unless advised otherwise, and take extra care during illness with vomiting or diarrhoea.

Kidney stones and gout

Some people develop kidney stones or gout after certain treatments. Report sudden severe back or side pain or painful swollen joints.

Children's kidney follow-up

Children treated with ifosfamide or cisplatin may need periodic blood, urine and blood pressure checks into adulthood.

Pregnancy planning

Women with reduced kidney function should discuss pregnancy plans with their doctor, as pregnancy places extra demand on the kidneys.

Keeping kidney results

Keep copies of kidney blood test results so trends over time can be compared.

When a kidney specialist helps

A kidney specialist can advise on diet, medicines and monitoring if kidney function falls or salts remain low despite supplements.

Contrast scan precautions

Before scans with contrast dye, doctors may check kidney function and give fluids to protect your kidneys.

Living well with reduced kidney function

Many people with mildly reduced kidney function live normal lives with sensible precautions and regular checks.

What to do next

Ask whether your treatment affected your kidneys, have recommended blood, urine and blood pressure checks, control blood pressure and sugar, stay hydrated, avoid harmful painkillers, tell scan teams about your history, and report warning signs promptly.