Background: Tenfold errors in medication dosing continue to occur despite being a well-recognized risk, particularly to pediatric patients. Few systematic evaluations of the characteristics and causes of tenfold medication dosage prescribing errors have been performed.
Objective: To identify and quantify the characteristics of tenfold medication dosage prescribing errors.
Design: Evaluation of 200 consecutively detected medication orders with tenfold errors in dosing in a 631-bed tertiary-care teaching hospital.
Main outcome measures: Type, frequency, characteristics, causes, enabling factors, and potential for adverse effects of tenfold medication dosage prescribing errors.
Results: Two hundred cases of tenfold prescribing errors were detected over an 18-month period. Overdoses were prescribed in 61% of the cases and underdoses in 39% of the cases. Ninety (45%) of the errors were rated as potentially serious or severe; 19.5% of the errors ocurred in pediatric patients. Levothyroxine accounted for 19% of all errors. As a class, antimicrobials, cardiovascular agents, and central nervous system agents each accounted for > or =15% of errors. Errors were associated with multiple zeroes in the dose (45%), use of equations or calculations to determine dose (27% total cases, 92.3% of pediatric cases), dose amount less than 1 (25%), and expression of measure conversion (23%). The tenfold errors were produced by a misplaced decimal point in 87 cases (43.5%), adding an extra zero in 63 cases (31.5%), and omitting a zero in 50 cases (25%). Factors identified as enabling a tenfold error to be carried out as ordered were a wide dose range for the drug (76.5%), medication ordered and able to be given by injection (42%), ability to give ordered dose as < or =5 solid oral dosage forms (36%), and availability of an oral liquid dose form (15%).
Conclusions: Prescribing of tenfold medication dose errors is common and is associated with identifiable risk factors. Implementing commonly recommended medication safety processes are likely to reduce risk to patients from such errors. This information should be considered in the development of strategies to prevent adverse patient outcomes resulting from such errors.