Indications
Furosemide is a strong “water tablet” (diuretic). It is used to remove extra fluid from the body (oedema) caused by heart failure, liver disease or kidney disease, and sometimes to treat high blood pressure. The injection is used in hospital for urgent problems such as fluid on the lungs.
How It Works
Furosemide is a loop diuretic. It stops part of the kidney (the loop of Henle) from taking salt and water back into the blood, so more salt and water leave the body as urine. This reduces swelling and breathlessness.
Dosage and Administration
- Adults, oedema: usually 20 to 40 mg once a day in the morning. The doctor may adjust the dose depending on the response.
- High blood pressure: usually 20 to 40 mg a day, often with other medicines, as prescribed.
- Older people usually start on a lower dose.
- Children: dose depends on body weight, as prescribed.
Take tablets in the morning, so you are not up at night passing urine. If a second dose is prescribed, take it no later than early afternoon. The injection is given by a doctor or nurse.
Interactions
- Other blood pressure medicines may cause blood pressure to drop too low, especially with the first doses of ACE inhibitors such as Enalapril.
- Raises blood levels of Lithium, which can become toxic.
- Low potassium increases the risk of side effects from Digoxin.
- With Gentamicin and similar antibiotics, the risk of ear and kidney damage is higher.
- Painkillers such as Ibuprofen and Diclofenac can reduce its effect and harm the kidneys.
- Steroids such as Prednisolone add to potassium loss.
- Take Sucralfate at least 2 hours apart.
Contraindications
- Not passing any urine (kidney failure with no urine output).
- Severe dehydration or very low sodium or potassium in the blood.
- Coma caused by severe liver disease.
- Allergy to Furosemide or to sulfonamide medicines.
Side Effects
Common: passing urine more often, dizziness when standing up, thirst, dehydration, low potassium or sodium (muscle cramps, weakness, tiredness), raised uric acid which may trigger gout, raised blood sugar and skin rash.
Get urgent medical help if you faint, have a very dry mouth with little urine, an irregular or fast heartbeat, severe muscle weakness or confusion, ringing in the ears or hearing loss, a severe skin rash with blisters, or severe stomach pain.
Pregnancy and Lactation
Use in pregnancy only if the doctor decides it is necessary, as it can reduce blood flow to the baby. It passes into breast milk and may reduce milk supply; ask your doctor before using it while breastfeeding.
Precautions and Warnings
Regular blood tests for salts (sodium, potassium) and kidney function are usually needed. Use with care in older people and in those with diabetes, gout, low blood pressure, an enlarged prostate or difficulty passing urine, and liver disease. Stand up slowly to avoid dizziness. Your skin may burn more easily in the sun. Do not stop or change the dose without advice.
Overdose
Overdose can cause severe dehydration, very low blood pressure, salt imbalance, confusion and collapse. Get urgent medical help.
Therapeutic Class
Loop diuretic.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Keep injection ampoules in their carton to protect them from light.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.