Accuracy and precision of manufacturer-supplied liquid medication administration devices before and after patient education.

Objectives: To compare the accuracy and precision of a manufacturer-supplied dropper versus a pharmacy-supplied syringe when measured by a trained student pharmacist and to evaluate patients' ability to accurately measure a prescribed amount of medication with these devices before and after counseling on their use.

Methods: This was a two-phased study with a pretest/posttest design of 125 community pharmacy patrons of Virginia community pharmacies. Deliverable volume was measured by a student pharmacist for nystatin suspension and digoxin elixir using the manufactured-supplied device. Patients at pharmacies were asked to complete a short survey, then asked to measure a specified dose of nystatin suspension and digoxin elixir (using the manufacturer-supplied administration device). The patients repeated this a second time after a student provided education on how to properly use each administration device. The main outcomes measure was whether education on an administration device would provide more measurement accuracy using medications with different physical properties.

Results: For nystatin, 88% and 85.6% of patients measured with an error of greater than or equal to 20% before and after counseling, respectively. For digoxin, the totals were 24.8% before counseling and 4% after. A statistically significant (P < 0.05) difference was observed in the percent measurement error before and after counseling for nystatin and digoxin both for patients who had been educated before the study and for those who had not been counseled.

Conclusion: In general, the accuracy of medication dosage devices seems to be most affected by viscosity of the liquid being measured. With education on proper use, the oral syringe provides a statistically and clinically significant improvement in dosing accuracy for viscous medications compared with the manufacturer-supplied dropper. Pharmacists must review with patients the proper way to use a manufacturer- or pharmacy-supplied oral delivery device for appropriate dosing measurements.