Does Furosemide Cause Nausea?
Yes, furosemide can cause nausea as a gastrointestinal side effect, though it is not among the most commonly reported adverse reactions.
Evidence from FDA Drug Labeling
The FDA label for furosemide explicitly lists gastrointestinal disturbances such as nausea and vomiting as potential manifestations of fluid or electrolyte imbalance that may occur during therapy 1. Specifically, the label states that patients should be observed for signs of electrolyte depletion including "gastrointestinal disturbances such as nausea and vomiting" 1.
Clinical Evidence on Adverse Reaction Frequency
- In a large surveillance study of 2,367 hospitalized patients receiving furosemide, adverse reactions were attributed to the drug in 10.1% of cases 2.
- The most common adverse reactions in this cohort were intravascular volume depletion (4.6%), hypokalemia (3.6%), and other electrolyte disturbances (1.5%) 2.
- While nausea was not specifically quantified as a separate adverse event in this study, gastrointestinal symptoms were recognized as part of the adverse reaction profile 2.
Mechanism and Clinical Context
Nausea from furosemide typically occurs as a secondary effect of electrolyte disturbances rather than as a direct drug effect. The FDA label emphasizes that all patients receiving furosemide should be monitored for signs of fluid or electrolyte imbalance, which can manifest as gastrointestinal symptoms including nausea 1.
Key Electrolyte Disturbances That Cause Nausea:
- Hypokalemia - particularly with brisk diuresis or inadequate oral electrolyte intake 1
- Hyponatremia - from excessive fluid loss 1
- Hypomagnesemia - which should be monitored periodically 1
Monitoring and Prevention
- Serum electrolytes (particularly potassium), CO2, creatinine, and BUN should be determined frequently during the first few months of therapy and periodically thereafter 1.
- Serum and urine electrolyte determinations are particularly important when the patient is vomiting profusely 1.
- The frequency of adverse reactions, including gastrointestinal symptoms, increases progressively with higher daily doses of furosemide 2.
Important Clinical Caveat
If nausea develops during furosemide therapy, check electrolytes immediately before attributing it solely to the drug itself. Correcting underlying electrolyte abnormalities will often resolve the nausea 1. The drug should be temporarily withdrawn if severe electrolyte abnormalities are present 1.