Problem: The Food & Drug Administration would like to alert healthcare providers to medication errors involving confusion between Metadate ER and Metadate CD. Practitioners should be cautious when
Between 2001 and 2002, the FDA received nine cases of medication errors involving these products. Six reports describe multiple occurrences of errors in which prescriptions written for Metadate CD were incorrectly filled and dispensed as Metadate ER. Two reports identify the reverse-Rxs written for Metadate ER but incorrectly filled and dispensed as Metadate CD. The remaining report involves concerns over the similarity of the names. None of the reports indicated any adverse outcomes.
Metadate ER and Metadate CD are methylphenidate extended-release products; however, they are not substitutable. Metadate CD is a once-a-day capsule with biphasic release; initially there is a rapid release of methylphenidate, then a continuous-release phase. Metadate ER, on the other hand, is a tablet given two to three times per day. Metadate ER may be titrated to eliminate the need for midday dosing.
Similarities in labeling and packaging were also noted. A comparison of the current Metadate ER and Metadate CD product labeling and packaging demonstrates commonalties between the products that may contribute to the confusion. Each label has a large blue or gray band, which includes the drug name, and a smaller (gray or blue) band with a boxed strength.
Currently, the Metadate CD 10-mg and 30-mg strengths are differentiated by either a red or green color. Metadate CD 20-mg and Metadate ER 10-mg and 20-mg labels all have a blue-gray color scheme used to highlight the name and strengths. In the past, Metadate CD 20 mg was available only in a 30-capsule dose pack, but now it is also available in 100-count bottles, which may also lead to confusion when comparing with Metadate ER.
Recommendation: One way to help prevent dispensing and selection errors is to separate Metadate ER and Metadate CD products if they are stored in close proximity on the pharmacy shelf or in a locked vault. When double-checking Rxs, pharmacists should verify the daily dosing regimen against what is being prescribed. This is especially important, as Metadate ER and Metadate CD are not substitutable. Additionally, the FDA would be interested in learning about more of these types of medication errors. Medication errors may be reported through the FDA MedWatch Adverse Event Reporting System at http://www.fda.gov/medwatch/.