Between them, the five researchers split 3600 pills into halves or quarters, using various methods, including a pill-splitter. Some of the pills were pre-scored, others were not. The scientists found that splitting tablets very often results in uneven dosages. For one thing, tablets are often not split into exactly equal parts. For another, some material is usually lost at the cut site, making the total of the remaining pieces less than the original was. Even under the best conditions, a sizeable fraction of the resulting fragments were up to one quarter bigger or smaller than expected.
Although this may not matter for some medications, others require tightly controlled dosing. For this reason, the researchers suggest that whenever possible patients use either pills formulated to their exact dosage or liquids, rather than splitting pills. If pills must be split, using a pill-splitter rather than a knife or other implement yielded the most accurate results.