The National Health Service has issued important safety guidance for the millions of Britons prescribed the diuretic medication furosemide, urging specific groups to seek medical advice before use. This comes as the drug, commonly used to manage conditions like heart failure and hypertension, was dispensed approximately 11 million times in 2024, ranking it among the UK's top 20 most prescribed medicines.
Key Groups Advised to Consult a Doctor
To ensure safe use of furosemide, NHS guidance explicitly recommends that eight distinct groups of people should speak with a GP before starting or continuing the prescription. This critical advice is aimed at preventing serious complications.
The list crucially includes anyone displaying tell-tale signs of dehydration, such as persistent thirst, a dry mouth, or passing dark-coloured urine. The health service stresses that individuals in this category must seek professional medical opinion.
The full list of groups advised to consult a doctor encompasses:
- Anyone who has previously had an allergic reaction to furosemide or any other medicine.
- Individuals experiencing low blood pressure (hypotension).
- Those diagnosed with liver disease.
- People with a diabetes diagnosis.
- Anyone who struggles to urinate.
- Individuals diagnosed with Addison's disease, a rare disorder of the adrenal glands.
- Those diagnosed with gout.
Additional Precautions and Medication Interactions
Beyond the initial consultation, the NHS advises furosemide users to inform their doctor if they are due for specific medical procedures. This includes upcoming glucose tests, scans involving iodine-based dye injections, or any major operation requiring a general anaesthetic.
Perhaps one of the most vital warnings concerns potential interactions with other drugs. Furosemide's effectiveness can be reduced, or the risk of side effects increased, when taken alongside certain common medications.
Patients must consult their doctor before combining furosemide with:
- Specific mental health medicines like amisulpride, lithium, or risperidone.
- Other blood pressure medications or drugs with a side effect of lowering blood pressure.
- The ulcer treatment sucralfate (requiring a two-hour gap from furosemide dose).
- NSAID painkillers like ibuprofen, diclofenac, or naproxen.
- Medicines affecting blood potassium levels, including supplements, steroids, or other diuretics.
- Drugs for irregular heartbeat, such as digoxin or amiodarone.
- Common over-the-counter remedies like soluble paracetamol, co-codamol, and certain heartburn or indigestion treatments.
Understanding the 'Water Tablet'
Furosemide, which is only available via prescription in tablet or liquid form, belongs to a class of drugs known as diuretics. Often called 'water tablets', they work by increasing urine production to help the body eliminate excess fluid, thereby easing strain on the heart and circulatory system.
The NHS further cautions that there is insufficient evidence to confirm the safety of taking herbal remedies or supplements alongside furosemide, as these products are not subjected to the same rigorous testing as prescription medicines.
With its widespread use, this updated guidance serves as an essential reminder for patients and prescribers alike to review individual health circumstances and medication regimes carefully to ensure the safe and effective use of this common treatment.
