Dialogue Volume 13 Issue 2 2017 - Page 46

practice partner Express levothyroxine doses in micrograms not milligrams P hysicians are being urged to express doses of levothyroxine in micrograms not milligrams after the Institute for Safe Medication Practices (ISMP) Canada became aware of errors involving the medication. “Multiple cases of errors and near misses involving the levothyroxine dose conversions from milligrams (mg) to micrograms (mcg) and vice versa have been reported to ISMP Canada and in the literature,” stated a recent ISMP bulletin (Volume 17, Issue 3) The Canadian manufacturer of levothyrox- ine labels express levothyroxine doses in mi- crograms (mcg) only. However, throughout the medication-use process (e.g., prescribing, dispensing, and administration), the thyroid medication doses may be expressed in micro- grams (mcg) or in milligrams (mg). As a result, patients and health-care providers may need to convert doses from milligrams (mg) to micrograms (mcg), or vice versa, to match the prescribed dose to 46 Dialogue Issue 2, 2017 a particular product, leading to errors in calculations. A common calculation error occurs when converting between 0.025 mg and 25 mcg, causing a 10-fold error in dosing. The resul- tant dose, sometimes 250 mcg rather than 25 mcg, is considered a reasonable dose for some patients and, as such, does not raise a red flag for most practitioners. ISMP Canada strongly recommends that levothyroxine doses be expressed consis- tently in micrograms (mcg), not milligrams (mg), in all written or computer-generated prescriptions and health records, pharmacy systems, medication administration records, provincial/territorial drug databases, drug information systems, and patient materials. Using microgram units reduces the need for decimals (which can lead to errors), al- lows the dose to correspond directly to the manufacturer’s label (avoiding the need for conversion), and will standardize how levo- thyroxine information is communicated. MD Process of converting doses between different units of measurement blamed for errors