Keeping other health conditions under control during chemotherapy

It cannot tell you how your own conditions will respond to chemotherapy. That depends on the conditions, how well controlled they are and the medicines planned.

It also cannot tell you how to change any medicine. Only your doctors can make those decisions with you.

Before chemotherapy starts

A pre-treatment review looks at your other conditions, recent blood tests, kidney and liver function and sometimes a heart scan. This is the best moment to get conditions well controlled. Bring your medicine list, recent reports and the names of your other doctors so the cancer team can plan around them.

Steroids and blood sugar

Steroids such as dexamethasone are widely used with chemotherapy to prevent sickness and reactions. They can raise blood sugar for a day or two after each session, even in people without diabetes. Your team may ask you to check sugar more often and will advise if any change to diabetes treatment is needed.

Heart conditions

Some medicines, such as doxorubicin and epirubicin, and certain targeted treatments given alongside chemotherapy, can affect the heart. People with existing heart disease may need a heart scan before starting and during treatment. Your cardiologist and oncologist decide together whether a different medicine or closer checks are safer.

Kidney conditions

Medicines such as cisplatin and methotrexate are cleared by the kidneys and can strain them. If your kidneys are already weak, your oncologist may choose carboplatin or another option, or adjust the plan. Drinking enough fluid, unless you are told to limit it, helps protect kidney function during treatment.

Liver conditions

Many chemotherapy medicines are processed by the liver. Hepatitis B infection can flare during chemotherapy, so a blood test is often done first and preventive medicine may be advised. Existing liver disease may lead your team to adjust the plan. Report yellow skin or eyes, or dark urine, promptly.

Nerve damage from diabetes

Diabetes can already cause numbness in the feet, and medicines such as paclitaxel, oxaliplatin and vincristine can add further nerve damage. Tell your team about any numbness before starting. Check your feet daily, wear protective footwear, and report worsening tingling or balance problems so the plan can be reviewed.

Lung conditions

Asthma, chronic lung disease and past tuberculosis matter because chest infections are more likely when white cells are low. A few chemotherapy medicines can also affect the lungs. Keep inhalers available, ask about vaccines before treatment, and report new cough or breathlessness the same day.

Blood thinners

Many people take blood thinners for heart rhythm problems or clots, and cancer itself raises clot risk. When platelets fall, bleeding risk rises. Your doctors balance these risks carefully and may review the medicine. Never stop or change a blood thinner without speaking to them first.

Medicine interactions

Some everyday medicines, antibiotics, antifungals, epilepsy medicines and herbal products can interact with chemotherapy, changing its effect or side effects. Your oncologist and pharmacist check for interactions. Tell them about Ayurvedic, homoeopathic or other traditional remedies too, since these can matter as much as prescription tablets.

Mental health conditions

Depression, anxiety and other mental health conditions can be harder to manage during cancer treatment, and some psychiatric medicines interact with anti-sickness medicines. Keep seeing your psychiatrist or counsellor, tell them about your treatment, and let the cancer team know if mood, sleep or appetite changes.

Older adults and several conditions

Older people often have several conditions and take many medicines. A geriatric assessment, looking at strength, memory, nutrition and support at home, can help tailor treatment. Our pages on chemotherapy for older adults and other special situations explain this in more detail. Families can help by sharing what they notice at home.

Keeping records together

A single folder with your medicine list, blood sugar and blood pressure readings, recent reports and contact numbers for each doctor makes coordination easier. Bring it to every appointment. Ask the cancer team to send letters to your other doctors, and ask those doctors to copy results back.

What to do next

Tell your oncologist about every condition and medicine, ask which checks you need during treatment, agree who manages each condition, keep a record of readings, and never change a medicine without speaking to your doctors first.