Lasix with antibiotics: interactions and safety
Antibiotic courses are common, short-term and often combined with chronic medications such as Lasix (Furosemide). Most antibiotics do not interfere meaningfully with Furosemide at 20mg, 40mg, 100mg, but a few classes do, and a small number of combinations are best avoided.
Common antibiotic interactions
Macrolides (clarithromycin, erythromycin) and certain antifungals can inhibit hepatic metabolism (CYP3A4) and raise plasma levels of many medications including some Diuretics agents. Rifampicin has the opposite effect, accelerating metabolism. Most penicillins, cephalosporins, fluoroquinolones and tetracyclines have no clinically meaningful interaction with Furosemide at 20mg, 40mg, 100mg.
Practical guidance
According to the prescribing information for Furosemide, an antibiotic course should be reviewed by the prescriber or pharmacist for known interactions before Lasix is co-administered. Adjusted 20mg, 40mg, 100mg dosing or temporary substitution is sometimes preferred for the duration of the antibiotic course.
Frequently asked questions
Can I take Lasix during an antibiotic course? ▾
For most common antibiotics, yes. A few classes — notably macrolides and azole antifungals — alter how Furosemide is metabolised and may need a temporary 20mg, 40mg, 100mg adjustment. The prescribing pharmacist should review any new antibiotic against the existing Lasix regimen.
Will antibiotics make Lasix stop working? ▾
Most antibiotics do not affect Lasix efficacy. Rifampicin and a few others can lower Furosemide levels and reduce effect; in those cases the prescriber may adjust the dose during and shortly after the antibiotic course.
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