Extra caution needed with U-500 insulin

From the Jan. 29,1997 Issue

PROBLEM: Eli Lilly Co. has just announced it is replacing purified pork U-500 insulin with human U-500 insulin. This concentrated form is for use in patients with marked insulin resistance who would otherwise need large volumes of insulin solution if U-100 were used. Since a U-500 syringe is not available, Lilly recommends that either a U-100 insulin syringe or a tuberculin syringe be used to measure doses. But when patients receive U-500 insulin with a U-100 insulin syringe, doses are sometimes miscommunicated by 5-fold. A patient using U-500 insulin with a U-100 syringe might state his dose as "40 units" when in reality he is reading "40 units" on the U-100 scale, but actually receiving 200 units.

SAFE PRACTICE RECOMMENDATION: Warning! Use extreme caution when expressing or interpreting doses of U-500 insulin. Consistent use of a tuberculin syringe with U-500 insulin is recommended, with total doses expressed in terms of both units and volume. For example, "200 units (0.4 mL)." Educate staff and patients about potential problems. Incorporate special quality assurance checks into preparation and handling of this drug in healthcare facilities. This product should also never be used intravenously because of the extremely serious nature of any inadvertent overdose. [D,N,P]