Journal of the American Pharmaceutical Association (1996)
ResearchWeight Variability of Pharmacist-Dispensed Split Tablets
Section snippets
Objective
The purpose of this study was to determine the level of weight uniformity of split-tablet fragments that were dispensed by pharmacists.
Methods
Pharmacist-dispensed split-tablet samples were obtained from four long-term care facilities (LTCFs) in the New York City metropolitan area to which we provide consulting pharmacy services. The samples were collected from discontinued medications. These LTCFs obtained their prescription medications from three off-site pharmacies, each of which delivers medications twice daily to each facility. Collectively, these pharmacies provide medications to more than 100 LTCFs.
Twenty-two discontinued
Results
Table 3 lists the means and SDs of the TWs and FWs of the 22 different dispensed prescriptions. Statistically significant differences between these mean weights were found for 2 (9.1 %) of the 22 medications evaluated, doxazosin (Cardura—Roerig; Pfizer) 2 mg and venlafaxine (Effexor—Wyeth) 25 mg.
Table 4 shows that, overall, 30 (5.4%) of the 560 tablet fragments, contained in 10 (45.5%) of the 22 dispensed prescriptions, had weights that deviated by more than 15% from the mean FW. Overall, 32
Discussion
Tablet splitting has been the subject of debates focusing on issues of adherence and accuracy. Most recently, the National Association of Boards of Pharmacy approved a resolution opposing mandated tablet-splitting practices.12 Similarly, the American Pharmaceutical Association's position is that mandatory tablet splitting is bad practice.13 Likewise, the American Society of Consultant Pharmacists strongly opposes mandating tablet splitting by patients. This opposition stems from concerns about
Limitations
This investigation had several limitations. First, no established criteria exist for weight uniformity of tablet fragments created by pharmacists or patients. The criteria we applied to the samples were established to assure dosage uniformity of intact dosage units, not fragments. It is only for lack of other established guidelines that these criteria were applied in this study. If tablet splitting is considered extemporaneous compounding, an even stricter weight variation standard would be
Conclusion
In our study, only 7 (31.8%) of the 22 dispensed prescriptions met USP standards, with FWs not exceeding 15% of mean FW and SDs of no greater than 6%. This variance is unacceptable in terms of the usual standards for uniformity of dosage forms and of extemporaneously prepared pharmacy products.
Manufacturers should be encouraged to review pricing policies for various product strengths and to offer additional strengths of medications that meet the needs of all patients, especially pediatric and
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See related articles on pages 160 and 195.
The authors declare no financial interests or conflicts of interests in any product or service mentioned in this article, including grants, employment, gifts, stock holdings, and honoraria.