Tablet Splitting Yields Unpredictable Response

Researchers from Rutgers University set out to determine the effects when patients try to halve their doses of unscored tablets. They found that the drugs ended up differing in weight and content, thus resulting in unpredictable dosing and therapeutic response. Cyclobenzaprine hydrochloride in 10-mg tablets was used in the study; these tablets are round, film-coated, and unscored. Before splitting, the mean weight of 45 tablets was 136.6 mg +/- 2.1 mg, yielding a theoretical weight of 68.3 mg per perfectly split tablet.

The fragment weights were measured at 67.9 mg +/- 7.9 mg. The resulting weights proved that the tablet fragments, after splitting, yielded a significant difference in weight and estimated drug content. Therefore, in this particular study, dividing a 10-mg tablet of cyclobenzaprine in order to get a 5-mg dose could result in an uncertain dose level and an equally uncertain therapeutic response.