Furosemide was devoid of mutagenic activity in various strains of Salmonella typhimurium when tested in the presence or absence of an in vitro metabolic activation system, and questionably positive for gene mutation in mouse lymphoma cells in the presence of rat liver S9 at the highest dose tested. Furosemide did not induce sister chromatid exchange in human cells in vitro , but other studies on chromosomal aberrations in human cells in vitro gave conflicting results. In Chinese hamster cells it induced chromosomal damage but was questionably positive for sister chromatid exchange. Studies on the induction by furosemide of chromosomal aberrations in mice were inconclusive. The urine of rats treated with this drug did not induce gene conversion in Saccharomyces cerevisiae .
In fasted normal men, the mean bioavailability of furosemide from LASIX Tablets and LASIX Oral Solution is 64% and 60%, respectively, of that from an intravenous injection of the drug. Although furosemide is more rapidly absorbed from the oral solution (50 minutes) than from the tablet (87 minutes), peak plasma levels and area under the plasma concentration-time curves do not differ significantly. Peak plasma concentrations increase with increasing dose but times-topeak do not differ among doses. The terminal half-life of furosemide is approximately 2 hours.
Lasix is available in tablet (20 to 80 mg) and IV forms. Dosage is determined by the patient's physician and varies according to how much fluid and how fast the fluid should be removed. Patients with poor renal function usually require higher doses; doses in children are weight-based. Lasix may interact with sucralfate, cisplatin , cyclosporine, ethacrynic acid, lithium , methotrexate, phenytoin, antibiotics, heart or blood pressure medications, laxatives, salicylates such as aspirin, or steroids. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant while using Lasix; it is unknown if it will harm a fetus. Lasix passes into breast milk and may harm a nursing baby. Lasix may also slow breast milk production. Consult your doctor before breastfeeding.