Improving the safety of intravenous admixtures: lessons learned from a Pentostam overdose.

CASE STUDY: Weaknesses in the multistep process of admixture preparation and administration resulted in a patient with cutaneous leishmaniasis (CL) receiving a 10-fold intravenous (IV) overdose of Pentostam (sodium stibogluconalte), a rarely used drug. LESSONS LEARNED: A review of this adverse event resulted in five recommendations: (1) Provide staffing continuity among pharmacists and pharmacy technicians preparing and nurses administering the admixture; (2) Take time to ensure thorough and deliberative consideration ofquestions or concerns about admixture preparation; (3) Use due diligence in performing double checks of admixture calculations; (4) Know the drug and seek clarification when appropriate; and (5) Examine label information carefully. PROGRESS UPDATE: Two changes were made to improve patientsafety. First, a form was developed to accompany the preparation of complex IV drugs, including chemoltherapy solutions and nonformulary IV admixtures; the form is consistently used. Second, the pharmacy service developed information sheets for 12 high-risk drugs frequently used in IV admixtures. DISCUSSION: The medical center had processes in place to prevent medication errors, yet an error occurred nonetheless. Weaknesses were identified in staff communication, quality assurance checks, and product labeling. Also, nurses and pharmacists had less than adequate information about new or unusually dosed medications.

Sodium stibogluconate (pentostan) overdose in a patient with acquired immunodeficiency syndrome.

A 32-year-old man with acquired immunodeficiency syndrome (AIDS) admitted to the hospital for treatment of visceral leishmaniasis was inadvertently given 10 times the prescribed first dose of sodium stibogluconate ([Sb] 6.5 g instead of 0.65 g). He experienced no immediate major toxicity during the first 48 hours, but a significant rise of pancreatic enzyme activities was observed (amylase at 10 times the upper limit of normal, lipase at 50 times the upper limit of normal) without clinical signs or indications on computed tomography (CT) of pancreatitis. The third day after the overdose, he developed appendicitis, which appeared coincidental; he recovered uneventfully from surgery. Most of the overdose of Sb was eliminated within the first few hours. Pharmacokinetics remained linear; the rapid, long elimination half-lives (2.7 hours and 54 hours, respectively) were similar to those in previously published results. The administration of a chelating agent, dimercaptosuccinic acid (DMSA), 72 hours after the Sb overdose did not modify the pharmacokinetics of the medication.

Sodium stibogluconate (Pentostam) overdose during treatment of American cutaneous leishmaniasis.

A 27-year-old woman who acquired cutaneous leishmaniasis in Central America was inadvertently treated with 10 times the intended daily dose of the pentavalent antimonial compound sodium stibogluconate (Pentostam): 8500 mg (143 mg/kg) instead of 850 mg. The patient felt "wiped out" during the 4-h infusion of the drug. After the mistake in dosing was discovered, she was vigorously hydrated and carefully monitored in an intensive care unit for greater than 48 h. Her vital signs were stable, and no arrhythmias were noted. Her alanine aminotransferase level rose briefly to 2.4 times the upper limit of normal, and her white blood cell count briefly fell 43% to a low of 3700/microliter. Her skin lesions subsequently healed without further therapy. Although sodium stibogluconate has been associated with a variety of side effects, in this case, a single high dose of the drug was tolerated without serious toxicity.