From the May 29, 2003 issue

PROBLEM: Numerous cases of confusion between methylprednisolone acetate (DEPO-MEDROL) and methylprednisolone sodium succinate (SOLU-MEDROL) have been reported over the years. While both forms of the product are used to treat inflammation, dosing may differ, and the acetate form should never be administered intravenously (IV). Most recently we heard about a 3-year-old child in the emergency department (ED) who was prescribed Solu-Medrol 40 mg IV. The nurse accidentally selected methylprednisolone acetate 40 mg, which was the first form and strength of the generic methylprednisolone that appeared on the automated dispensing cabinet screen. Shortly thereafter, the pharmacist who entered the order for Solu-Medrol into the computer noticed that Depo-Medrol had been removed from the cabinet, and he called the unit to alert the nurse to the error. Fortunately, the nurse had already noticed that she had selected the wrong product and the child received the correct form of the drug.

ISMP Canada recently published an error in which another 3-year-old child did receive the acetate form of the drug IV. In this case, a daily outpatient infusion of Solu-Medrol 140 mg IV had been prescribed for the child, who had recently received an organ transplant at a large teaching hospital. The first dose was administered in the ED of a small community hospital on a Saturday when the pharmacy was closed. A nursing supervisor brought a box containing four vials of Depo-Medrol, each 40 mg, to the ED. The child’s nurse noticed the box of Depo-Medrol and assumed that the medication had been supplied by the hospital where the transplant was performed. Unfamiliar with Solu-Medrol, the nurse checked a drug reference text and found that both Solu-Medrol and Depo-Medrol listed methylprednisolone as part of their generic names. She erroneously assumed that both medications were brand names for equivalent products and administered Depo-Medrol 140 mg in 50 mL of saline IV to the child over 1 hour. The Pharmacia (now Pfizer) warning on the vial: “Not for IV use” is in very small print and is poorly visible (a photo appears in the PDF version of the newsletter), so that the nurse never noticed the warning. The error was not detected until the following day, when the child’s mother commented that the medication administered that day was clear while the medication given the day before had been cloudy. Fortunately, the patient did not experience an adverse effect. However, the manufacturer has received reports of adverse reactions, some severe, due to IV administration of Depo-Medrol. The United States Pharmacopeia also advised us that 48 reports of mix-ups between Solu-Medrol and Depo-Medrol have been received through their MEDMARX program in the past 5 years, mostly related to look-alike brand and generic names.

SAFE PRACTICE RECOMMENDATION: To reduce the risk of confusion between Solu-Medrol and Depo-Medrol, consider the following:

Increase awareness. Alert practitioners to the differences between Solu-Medrol and Depo-Medrol. Some may not be aware that the word “depo” or “depot” in association with a drug indicates slow release or slow absorption, with longer duration of action. Thus, these products are not intended for IV administration.

Dispense from pharmacy. Have pharmacy dispense methylprednisolone products or ensure that a pharmacist has reviewed the order before using products that are stocked on the unit.

Use alerts and reminders. Design a clinical alert for the acetate form of methylprednisolone to appear on automated dispensing cabinet screens to remind practitioners that the drug cannot be given IV. Affix a warning label, “IM use only” to the acetate form of methylprednisolone when dispensed (the manufacturer’s warning is poorly visible).

Improve the labeling. The manufacturer of Solu-Medrol and Depo-Medrol packages these products in similar-appearing cartons. This has contributed to occasional drug storage mix-ups and medication errors. The manufacturer’s warning “Not for IV use” on Depo-Medrol vials also needs to be more distinctive and visible. Another problem is that the 5 mL vial of Depo-Medrol contains benzyl alcohol, while the 1 mL vial does not. Again, this information is poorly visible, and with the 1 mL and 5 mL vials packaged in the same size cartons, mix-ups are possible (a photo appears in the PDF version of the newsletter). Only the preservative-free formulation can be given epidurally. If the form with preservatives is used by mistake, neural tissue injury can occur. We’ve previously alerted Pharmacia and minor changes were made, but errors persist.

Differentiate products. Solu-Medrol is available for purchase in a box of 25. When feasible (some may be experiencing a shortage), consider purchasing this product in bulk packaging instead of in individual cartons, which look similar to Depo-Medrol cartons. Once removed from the carton, the vials look very different. Also list methylprednisolone products in order entry computer systems using both brand and generic names to reduce the risk of mix-ups.