Hypersensitivity: Furosemide is a sulfur-containing diuretic and hypersensitivity reactions may occur, although they are rare; cross-reactivity with other sulfur-containing drugs is also possible.
Furosemide should be used with care in patients with prostatic hyperplasia or impairment or micturition since it can precipitate acute urinary retention. It should be used with caution during pregnancy and breast feeding since it crosses the placenta and also appears in breast milk. Furosemide may compromise placental perfusion by reducing maternal blood volume, it may also inhibit lactation.
Hepatic impairment: In patients with chronic heart failure and moderate liver congestion, high-dose furosemide therapy could produce increases in liver enzymes suggestive of hepatitis. Special care should be taken in such patients to avoid severe ischaemic liver damage caused by a drop in systemic blood pressure.
As with the thiazides, furosemide should be avoided in patients with severe hepatic impairment.