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| |  Splitting Cyclobenzaprine Hydrochloride Could Result in Inconsistent Dosing and Unpredictable Relief For Patients with Back Pain Variability in weight ranges and drug content of split muscle relaxant may put patients at risk of receiving too much/too little medication FORT WASHINGTON, PA -- September 21, 2004 -- A research study investigating the appropriateness of pill splitting suggests that back pain sufferers who divide a 10-mg tablet of the muscle relaxant cyclobenzaprine hydrochloride (HCl) in order to achieve a 5-mg dose may get anywhere from half to one-and-a-half times the amount of medicine they believe they are taking. This practice may either deprive them of the intended therapeutic benefit of the medication or expose them to unintended side effects such as drowsiness. The findings appear in the September/October issue of the Journal of the American Pharmacists Association. Following reports that patients given a prescription for the only available 5 mg dose of cyclobenzaprine HCl (Flexeril® 5 mg) were being advised to split higher dose 10 mg tablets instead, researchers at the Ernest Mario School of Pharmacy at Rutgers, The State University of New Jersey conducted a study to determine the level of weight variability of tablet fragments when the 10 mg tablets were split into halves with two commonly used devices -- a tablet splitter and a kitchen knife. “Ideally, an evenly split 10 mg tablet should have 100 percent of the half tablet weight and 5 mg of the medication,” explained study investigator Thomas J. Cook, Ph.D., Assistant Professor, Department of Pharmaceutics at Rutgers. “In this study, the variance in estimated drug content due to uneven tablet splitting ranged anywhere from 50 to 150 percent of the ideal targets, meaning a patient would have no guarantee of consistently receiving the intended amount of medication throughout the course of therapy.” Flexeril 5 mg is comparable in efficacy to the 10 mg strength, but has been shown to be significantly less sedating. Clinical research has demonstrated that doses of cyclobenzaprine lower than 5 mg are not effective for the treatment of acute painful muscle spasm of the back or neck. “Cyclobenzaprine HCl 10 mg tablets are not designed for splitting (tablets studied were film coated and unscored), so there is an increased likelihood that they will split unevenly, crumble or shatter, “ according to Dr. Cook. “Splitting unscored tablets to yield partial doses of a medication can result in uneven splitting that may, in turn, lead to dosing errors and variable efficacy and safety of the medication.” The National Association of Boards of Pharmacy adopted a resolution in 2001 opposing mandated tablet splitting, describing the practice as “potentially dangerous” and driven by monetary considerations rather than the patients’ best interests. The American Pharmacists Association (APhA) and the American Medical Association (AMA) have also stated that they formally oppose mandatory tablet splitting, and the APhA 2003-2004 Strategic Directions Committee recently proposed a practice tool to help pharmacists evaluate the appropriateness of tablet splitting in certain patient or product scenarios. Published in the May/June issue of the Journal of the American Pharmacists Association, the tool is designed to help pharmacists decide whether tablet splitting is appropriate based on certain product characteristics (i.e., is the tablet scored) and patient characteristics such as an individual’s dexterity, strength and visual acuity. “These considerations and the results of the current study strongly suggest that generic cyclobenzaprine HCl 10 mg tablets should not be cut in half,” added Dr. Cook. About the Study Dr. Cook, an Assistant Professor of Pharmaceutics and a licensed pharmacist, and two fourth-year Doctor of Pharmacy students at Rutgers’ Ernest Mario School of Pharmacy conducted the study, which evaluated the weight variability of 90 cyclobenzaprine HCl 10 mg tablets. Each of the three participants split a total of 30 tablets - 15 each with a commonly used tablet splitting device and a kitchen knife. Prior to splitting, each whole tablet was weighed on a special scale and the weight was recorded. The participants practiced the splitting technique with each device with up to four tablets; the weights of which were not included in the analysis. After each tablet was split, the individual fragment weights were measured and recorded. A theoretical half-fragment weight (THW) of each piece was used to calculate percent weight and drug content ranges from the average weight of the tablets for each trial. McNeil Consumer & Specialty Pharmaceuticals, U.S. marketers of Flexeril 5 mg tablets, sponsored the study.
About Flexeril 5 mg Flexeril 5 mg should be used for relief of painful muscle spasm along with rest and physical therapy. It should only be used for short periods of time, usually 2-3 weeks. Flexeril 5 mg is a prescription medicine and should not be taken by patients who have had a recent heart attack or have heart disease. It should not be used by people with an overactive thyroid or who are currently or have recently used MAOIs. Use of Flexeril 5 mg with MAOIs can result in serious health complications. Flexeril 5 mg may enhance the effects of alcohol and other medicines that work on the central nervous system. In clinical studies the most common side effects were drowsiness, dry mouth, and fatigue. For more information about Flexeril 5 mg, including full U.S. Prescribing Information, visit www.flexeril.info or call 1-888-440-7903. Reference herein to Rutgers, The State University of New Jersey, the Ernest Mario School of Pharmacy or faculty members of these institutions is intended for identification only and does not constitute an express or implied endorsement or recommendation by the institutions or their agents.
SOURCE: McNeil Consumer & Specialty Pharmaceuticals
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