Furosemide or frusemide is a loop diuretic used in the treatment of congestive heart failure and edema. It is most commonly marketed by Sanofi under the brand name Lasix, and also under the brand name Frumex. It has also been used to prevent Thoroughbred and Standardbred race horses from bleeding through the nose during races.
Along with some other diuretics, furosemide is also included on the World Anti-Doping Agency's banned drug list due to its alleged use as a masking agent for other drugs.
4-chloro-2-(furan-2-ylmethylamino)- 5-sulfamoylbenzoic acid
Furosemide is primarily used for the treatment of hypertension and edema. It is the first-line agent in most people with edema due to congestive heart failure. It is also used for hepatic cirrhosis, renal impairment, nephrotic syndrome, in adjunct therapy for cerebral/pulmonary edema where rapid diuresis is required (IV injection), and in the management of severe hypercalcemia in combination with adequate rehydration.
Although disputed, it is considered ototoxic: "usually with large parenteral doses and rapid administration and in renal impairment". Furosemide also can lead to gout due to hyperuricemia. Hyperglycemia is also a common side effect.
The tendency, as for all loop diuretics, to cause low potassium levels (hypokalemia) has given rise to combination products, either with potassium itself (e.g. Lasix-K) or with the potassium-sparing diuretic amiloride (Co-amilofruse).
What are the precautions when taking furosemide (Lasix)?
Before taking furosemide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, inability to make urine, gout, lupus.
If you have diabetes, furosemide may affect your blood sugar level. Check your blood sugar level regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication or diet.
What happens if I miss a dose?
Furosemide is sometimes used only once, so you may not be on a dosing schedule. If you are using the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include feeling very thirsty or hot, heavy sweating, or hot and dry skin.
What should I avoid while taking furosemide?
Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.
Avoid becoming dehydrated. Follow your doctor's instructions about the type and amount of liquids you should drink while you are taking furosemide.