Bradycardia after amphotericin, irradiation, and anthracycline

Amphotericin-induced heart-rate decrease in children

We describe six children with acute decreases in heart rate temporally related to amphotericin B administration. All patients had achieved their maximal dose within 3 to 4 days. Heart-rate drops occurred as early as day 3 but could be delayed up to day 7 after start of therapy. The mean heart rate dropped from 104 +/- 8/min (range 96 to 114) to 62 +/- 8/min (range 48 to 72) (P = 0.0001). A slower heart rate than baseline was noted during the entire duration of drug administration, from 60 minutes of starting the infusion to 220 minutes (mean 120 +/- 40) after discontinuation of the infusion. This reaction was noted in six of 90 (6.7%) patients who had amphotericin. These six children were compared with six age-matched children who received the drug but in whom such changes in heart rate did not develop. The method of administration of amphotericin B was similar in both patients and controls, starting with 0.25 mg/kg/day and increasing by 0.25 mg/kg/day up to 1 mg/kg/day. Children with heart-rate drop received amphotericin for 4.6 +/- 1.8 days, significantly shorter than their controls (12.6 +/- 6.9 days) (P = 0.02), suggesting that this adverse effect has led to early discontinuation of amphotericin therapy. Physicians and nurses caring for children receiving amphotericin B should be aware of this potential adverse effect, which can be serious in a patient with an underlying heart condition or in a patient who is already on heart-rate-lowering drugs.

Rapid infusion of amphotericin B in dextrose

OBJECTIVE

To review the data examining the use of rapid infusion of amphotericin B in dextrose infusions.

DATA SOURCES

A MEDLINE search of the English-language literature and review of pertinent references' bibliographies was used to identify articles evaluating the effect of amphotericin B infusion rates on the incidence of adverse reactions.

STUDY SELECTION AND DATA EXTRACTION

Controlled and uncontrolled studies involving humans are reviewed; emphasis is placed on recent comparative trials. Pertinent information, as judged by the authors, was selected for discussion.

DATA SYNTHESIS

Amphotericin B, a polyene antifungal agent with significant toxicity, remains the agent of choice for many serious fungal infections. The potential benefits of rapid administration of amphotericin B in reducing the incidence and/or severity of adverse reactions were noted soon after its introduction. Recent studies have examined the tolerability of rapid (0.75-1 h) amphotericin B infusions. Results of studies assessing the tolerability of rapid amphotericin B infusions suggest that tolerance to infusion-related reactions develops during therapy. Comparative trials have obtained variable results. The comparative trials supporting rapid amphotericin B infusion have generally used crossover designs, enrolled small numbers of patients, and excluded patients with significant renal or cardiovascular dysfunction.

CONCLUSIONS

Rapid amphotericin B infusions should be avoided during initiation of therapy when infusion-related reactions tend to be most problematic, and in patients with cardiovascular disease, renal dysfunction, and potassium disorders because of the potential risk for cardiac arrhythmias. The literature currently available is conflicting and insufficient to support the routine use of rapid amphotericin B infusion.