From the Guidelines
Yes, Lasix (furosemide) can cause both dehydration and hyperchloremia. Furosemide is a potent loop diuretic that works by inhibiting sodium and chloride reabsorption in the ascending loop of Henle in the kidneys, leading to increased urinary excretion of water, sodium, chloride, potassium, and other electrolytes, as described in the guidelines for liver cirrhosis management 1. The rapid fluid loss can result in dehydration, especially if fluid intake is inadequate or if the dose is too high. Hyperchloremia (elevated chloride levels in the blood) can occur because furosemide causes proportionally greater excretion of sodium than chloride, potentially leading to a relative excess of chloride. This is particularly common in patients receiving high doses or prolonged therapy. Some key points to consider when using furosemide include:
- Monitoring for signs of dehydration such as excessive thirst, dry mouth, decreased urination, dizziness, or lightheadedness
- Regular electrolyte monitoring, especially in elderly patients, those with kidney or liver disease, or patients taking other medications that affect electrolyte balance
- Ensuring adequate fluid intake to prevent dehydration
- Using the smallest effective dose to minimize the risk of complications, as recommended in the guidelines 1. It is essential to weigh the benefits of furosemide against the potential risks and to closely monitor patients to minimize the risk of dehydration and hyperchloremia.
From the FDA Drug Label
PRECAUTIONS General Excessive diuresis may cause dehydration and blood volume reduction with circulatory collapse and possibly vascular thrombosis and embolism, particularly in elderly patients. The principal signs and symptoms of overdose with Furosemide are dehydration, blood volume reduction, hypotension, electrolyte imbalance, hypokalemia and hypochloremic alkalosis, and are extensions of its diuretic action.
Dehydration and Electrolyte Imbalance: Yes, Lasix (furosemide) can cause dehydration and electrolyte imbalance, including hypochloremia (low chloride levels).
- Dehydration: is a potential side effect of excessive diuresis caused by furosemide.
- Hyperchloremia: (elevated chloride levels) is not directly mentioned in the drug label as a potential side effect of furosemide. Instead, hypochloremic alkalosis (low chloride levels) is listed as a sign of overdose. Therefore, based on the information provided, furosemide is more likely to cause hypochloremia rather than hyperchloremia 2, 2, 3.
From the Research
Dehydration and Electrolyte Imbalance
- Dehydration is a potential side effect of Lasix (furosemide) due to its diuretic properties, which increase urine production and lead to fluid loss 4, 5.
- The study by 4 found that dehydration was one of the most important clinical events associated with furosemide administration, occurring in a significant proportion of patients.
- Another study 5 demonstrated that diuretic-induced dehydration can impair heat tolerance and increase the risk of heat exhaustion during exercise in hot environments.
Hyperchloremia
- However, the study by 4 found that furosemide-induced hypochloremia (low chloride levels) occurred in 35.8% of patients, rather than hyperchloremia (high chloride levels).
- There is no evidence in the provided studies to suggest that Lasix (furosemide) causes hyperchloremia.
- Other studies 6, 7, 8 do not provide information on the effects of furosemide on chloride levels.
Electrolyte Abnormalities
- Furosemide can cause various electrolyte abnormalities, including hypokalemia (low potassium levels) 4, 7, 8, hypochloremia 4, and hyponatremia (low sodium levels) 4, 7.
- The study by 8 reported a case of severe hypokalemia with rhabdomyolysis (muscle breakdown) induced by furosemide abuse.
- The study by 7 found that furosemide increased the risk of acute kidney injury and hypokalemia in patients with syndrome of inappropriate antidiuresis (SIAD).