Risk factors for nephrotoxicity associated with conventional amphotericin B therapy

Drug-induced acute kidney injury

PURPOSE OF REVIEW

The purpose of this review is to describe the most prevalent mechanisms of drug-induced acute kidney injury, to define the risk factors for nephrotoxicity, and to analyze the available evidence for preventive measures.

RECENT FINDINGS

Drug toxicity remains an important cause of acute kidney injury that, in many circumstances, can be prevented or at least minimized by vigilance and early intervention. Recent studies have resulted in increased insight into the subcellular mechanisms of drug nephrotoxicity. Further improvement is to be expected from the identification of early markers of nephrotoxicity and an increasing involvement of a clinical pharmacist.

SUMMARY

The main mechanisms of nephrotoxicity are vasoconstriction, altered intraglomerular hemodynamics, tubular cell toxicity, interstitial nephritis, crystal deposition, thrombotic microangiopathy, and osmotic nephrosis. Before prescribing a potentially nephrotoxic drug, the risk-to-benefit ratio and the availability of alternative drugs should be considered. Modifiable risk factors should be corrected. The correct drug dosage should be prescribed. Patients should be pre-hydrated and the glomerular filtration rate should be frequently monitored during the administration of a potentially nephrotoxic drug. Studies are needed to further elucidate the mechanisms of nephrotoxicity to design more-rational prevention and treatment strategies. Computer-based prescriber-order entry and an appropriately trained intensive care unit pharmacist are particularly helpful to minimize medication errors and adverse drug events.

Effects of hydration with salt repletion on renal toxicity of conventional amphotericin B empirical therapy: a prospective study in patients with hematological malignancies

OBJECTIVE

Several studies have suggested that hydration and sodium load might reduce nephrotoxicity related to amphotericin B-deoxycholate (AmB-d). However, a schedule of these nephroprotective measures has not been standardized until now. A protocol of hydration and electrolyte supplementation was used prospectively in patients with hematological malignancies receiving empirical AmB-d treatment to evaluate its effect on AmB-d-related renal toxicity.

PATIENTS AND METHODS

A total of 77 consecutive patients received AmB-d (1 mg/kg per day) in association with an initial intravenous hydration of at least 1 l/m2 body surface, containing at least 1 l of 0.9% saline daily. Hydration was increased when serum creatinine levels showed a 20% increase from baseline. Serum electrolytes were replaced when indicated.

RESULTS

The median duration of AmB-d therapy was 14 days. The mean intravenous hydration and the mean diuresis were 1530 and 1970 ml/m2 of body surface per day, respectively. Overall, 55 patients (71.4%) received a mean of 18.5 days of therapy without dose-limiting adverse events. Despite significant increases in mean creatinine serum levels and decreases in mean creatinine clearance observed early in the whole population, in only six patients (7.8%) was therapy discontinued due to renal failure, which always recovered after treatment discontinuation. In eight patients (10.4%) therapy was stopped due to infusion-related side effects. Seven patients died while under antifungal therapy without relevant signs of AmB-d-associated toxicity.

CONCLUSIONS

Our prospective experience confirms that adequate hydration (about 1500 ml/m2 of body surface) and careful electrolyte supplementation are simple measures able to contain nephrotoxicity and to permit adequate antifungal therapy at least in the empirical setting.