Summary

The combination of Amphotericin B and Furosemide presents a significant drug interaction with increased risk of nephrotoxicity and electrolyte imbalances. Both medications can cause kidney damage, and their concurrent use may lead to additive renal toxicity requiring careful monitoring and potential dose adjustments.

Introduction

Amphotericin B is a polyene antifungal medication primarily used to treat serious systemic fungal infections, particularly in immunocompromised patients. It belongs to the class of antifungal agents that work by binding to ergosterol in fungal cell membranes. Furosemide is a potent loop diuretic commonly prescribed for treating fluid retention (edema) and hypertension. It works by inhibiting sodium and chloride reabsorption in the ascending limb of the loop of Henle in the kidneys, promoting diuresis and electrolyte excretion.

Mechanism of Interaction

The interaction between Amphotericin B and Furosemide occurs through additive nephrotoxic effects on the kidneys. Amphotericin B causes direct renal tubular damage and vasoconstriction of renal arterioles, leading to decreased glomerular filtration rate and acute kidney injury. Furosemide can exacerbate this nephrotoxicity by causing volume depletion, electrolyte imbalances (particularly hypokalemia and hypomagnesemia), and further reduction in renal blood flow. The combination may also increase the risk of ototoxicity, as both drugs can potentially cause hearing damage through different mechanisms.

Risks and Symptoms

The primary clinical risks of combining Amphotericin B and Furosemide include acute kidney injury, chronic kidney disease progression, severe electrolyte imbalances (hypokalemia, hypomagnesemia, hyponatremia), and potential ototoxicity leading to hearing loss. Patients may experience decreased urine output, elevated serum creatinine and blood urea nitrogen levels, and symptoms of electrolyte disturbances such as muscle weakness, cardiac arrhythmias, and neurological complications. The interaction is considered clinically significant and requires immediate attention and monitoring.

Management and Precautions

Management of this drug interaction requires frequent monitoring of renal function (serum creatinine, BUN, creatinine clearance), electrolyte levels (potassium, magnesium, sodium), and fluid balance. Consider using liposomal formulations of Amphotericin B when possible, as they have reduced nephrotoxicity. Ensure adequate hydration and consider electrolyte supplementation as needed. Monitor for signs of ototoxicity through audiometric testing if prolonged therapy is required. Dose adjustments or alternative medications should be considered based on renal function and clinical response. Close collaboration between healthcare providers is essential for safe concurrent use of these medications.

Amphotericin B interactions with food and lifestyle

Furosemide interactions with food and lifestyle

Furosemide should be taken with food or milk to reduce stomach upset. Alcohol consumption should be limited as it can increase the risk of dehydration and low blood pressure when combined with furosemide. Patients should maintain adequate fluid intake unless specifically restricted by their healthcare provider, as furosemide can cause dehydration. Salt substitutes containing potassium should be used cautiously, as furosemide can affect potassium levels. Excessive sun exposure should be avoided as furosemide may increase sensitivity to sunlight.