Bumetanide: what it treats and how to take it safely

Bumetanide is used when fluid has collected in the body and shows up as swollen ankles, legs or abdomen. The NHS names three underlying causes: heart failure, chronic kidney disease and severe liver damage. In each, the body holds on to salt and water that it should be getting rid of.

The tablet acts on the kidneys so that more fluid leaves as urine, which is why diuretics are known as water tablets. Treating the swelling relieves symptoms such as breathlessness and heaviness; it does not remove the cause, so the underlying condition is managed separately.

Treatment normally begins at a low dose. The NHS says it may be increased after a week or more, and that you will typically take it once a day, with some people moving to twice daily. When there are two doses, the second is taken in late afternoon rather than evening, so sleep is less likely to be disturbed.

You can take it with or without food and should swallow it with water. Because it acts quickly on the bladder, it helps to stay near a toilet for a while after each dose. Stay alert to fluid loss if you are ill with vomiting, diarrhoea or a fever, because dehydration becomes more likely.

• Same time each day, ideally in the morning for a once-daily dose.

• Ask your doctor how much to drink, since fluid advice depends on your condition.

• Speak to a pharmacist or doctor before your first dose after any illness that involves fluid loss.

Most adults and children can take bumetanide. The NHS lists the following as reasons it may be unsuitable: an earlier allergic reaction or serious side effect from bumetanide or another diuretic, low blood salt or potassium, low blood pressure, diabetes and gout.

Where benefits outweigh risks the medicine may still be used, usually with extra checks. Describe your full history to the prescriber, including any gout flare-ups, because that detail can change the choice of treatment.

Everyday effects include thirst, tiredness, a dry mouth, headaches, dizziness from low blood pressure, nausea, itchy skin, muscle pain and cramps, and drowsiness. Many of these ease over a few weeks.

Less often, bumetanide can cause anaphylaxis, severe dehydration, tinnitus or hearing loss, and kidney problems. Signs of severe dehydration include peeing very little, sunken eyes and confusion. Kidney warning signs are back or side pain, high temperature and passing blood in the urine. Contact NHS 111 about suspected serious effects, and use 999 where an ambulance is advised, for example anaphylaxis. Do not drive if you feel dizzy or drowsy.

The NHS lists lithium, anti-inflammatory painkillers such as ibuprofen and diclofenac, digoxin, certain antibiotics and antifungal medicines, and some blood pressure drugs such as ACE inhibitors as able to interact with bumetanide. Always mention it when someone prescribes a new medicine or when you buy a remedy from a pharmacy.

Alcohol is best avoided. It increases dizziness, light-headedness and dehydration, and combined with a diuretic the effects can be stronger than expected.

Bumetanide is not usually used in pregnancy or during breastfeeding, and it is only considered if the benefits are judged to outweigh the risks, in which case the lowest effective dose is chosen.

If a dose is missed, take it when remembered unless the next dose is due, and never double up. People on long-term treatment are offered regular blood tests. Keep taking the tablets as prescribed unless a clinician tells you otherwise, as stopping can allow fluid to return.