A new study suggests widespread inconsistencies in dosing directions for over-the-counter children’s liquid medications.

The study is scheduled to appear in the December 15 issue of the Journal of the American Medical Association. However, JAMA released the study online this afternoon “because of its public health importance.”

The study began in late 2009, when the Food and Drug Administration issued voluntary guidelines to promote greater consistency and clarity in OTC medications. The FDA recommendations call for measuring devices to be included with all OTC liquid medications and clearer, more uniform labeling of quantities.

The guidelines came in response to reports of unintentional drug overdoses among children.

The study sought to determine how prevalent dosing inconsistencies were at the time when the FDA actually issued these guidelines. Researchers found problems with a majority of the leading pediatric analgesic, cough/cold, allergy and gastrointestinal OTC oral liquid products.

Of the 200 products surveyed, 52 (26 percent) came without measuring devices. And of the 148 products with measuring devices, the study found “inconsistencies between the medication’s dosing directions and markings on the device” in 146 cases (98.6 percent).

In some cases, the directions on the box refer to different units of measurement than those printed on the measuring device.

More common problems include the use of nonstandard abbreviations for measuring units.  Some products abbreviate milliliter as “ml” instead of “mL” and teaspoon as “TSP” instead of “tsp.”

The study also suggests OTC children’s medicines need to be clearer in labeling fractions. A common practice is to label one-half as .5 — which public health experts suggest could lead to a ten-fold error if a parent inadvertently reads it as 5. A clearer notation is to place a zero before the decimal, as in 0.5, according to the FDA recommendations.

“What we really hope will happen is that there will be work to set some standards,” said Ruth Parker, MD, of Emory University, one author of the study. “So that from the consumer standpoint it’s easier to pick up a medicine, read the label, look at the measuring device and know with confidence how much of it you give.”