A 56-year-old African American male patient of yours with a history of type 2 diabetes mellitus, hypertension, gout, and post-traumatic stress disorder (attributed to his wartime service in Vietnam) was recently diagnosed with prostate cancer and is scheduled for a prostatectomy 1 week from now.
At about 4 P.M., while driving with his wife (she is at the wheel), he starts sweating, slurring his speech, and feeling drowsy. His wife heads to the emergency department (ED), where his glucose level by fingerstick is found to be 37 mg/dL. He receives an infusion of dextrose 50% and his symptoms promptly resolve. The patient says he has not missed any meals and that he has been taking his medications as prescribed. He was seen in the same ED yesterday after a brief syncopal attack that was also attributed to hypoglycemia. The patient is admitted to the hospital under the family medicine residency service for further monitoring and management of recurrent hypoglycemia. Since you are the primary doctor, the admitting resident calls you.
You pay the patient a visit and ask him about his medications. He shows you the list and says he is taking them all “faithfully.” You note that the list contains both glipizide (which he has misspelled as “glipizine”) and Glucotrol (a branded version of glipizide). When queried on this point, he insists these are different medicines your office prescribed for him, and he is taking both. This therapeutic duplication, you suspect, is the likely cause of his recurrent episodes of hypoglycemia.
You review your outpatient records (you do not have an EMR) and discuss events in more detail with the patient and his wife. One month ago, the patient came to your office for a routine follow-up visit. You were out of town, so he saw one of your colleagues. He recalls that the doctor told him his sugar levels were too high and gave him a prescription, instructing him to take it with-out fail. He already had enough Glucotrol XL at home and had not requested a refill, so he assumed this was a new medication. He does not recall reading the prescription. The outpatient record shows that the patient had admitted to missing doses of his Glucotrol XL and that the covering physician attributed the hyperglycemia to this poor compliance. The physician had therefore decided to keep the dose of Glucotrol XL the same, provided a refill of Glucotrol XL 10 mg daily, and counseled the patient to improve compliance.
The patient took the script to his usual pharmacy, but they had just closed. He went instead to another nearby pharmacy (part of another chain), where he had the prescription filled. The bottle was labeled by the pharmacy: Glipizide XL 10 mg. Since that date he has been taking both Glucotrol and glipizide and, following the physician’s advice, has not missed a dose.
Q: How could this duplication have occurred?
A:___________________________________________________________
Better monitoring systems needed
Therapeutic duplication (referring, in general, to the use of more than one medication from the same class) is a serious problem, as illustrated by this case. A study of 208 elderly patients on 5 or more medications at a general medical clinic in North Carolina found therapeutic duplication in 5.7% of patients.1 In a Canadian study involving 12,560 elderly patients in primary care settings, the rate was 4%.2 Rates in other settings have been found to be higher (21% of 1854 nursing home residents in Sweden,3 and 15% of 259 patients newly enrolled in a home healthcare pro-gram in New York and California.4) In this case we have a patient taking 2 different preparations of the same drug. The causes of therapeutic duplication have not been well studied, but potential reasons are outlined in TABLE 1.
Current systems go only so far. Practices that have well-maintained medication lists on paper or as part of an electronic medical record are in a good position to avoid duplicate prescribing. However, tracking systems restricted to an office practice will not prevent duplications made by consultants or hospital physicians.
Pharmacies generally have software that checks for therapeutic duplication, thereby allowing pharmacists to alert physicians of the potential problem. This works well if a patient uses one pharmacy exclusively. But in the case at hand, the patient elected to go to a different pharmacy instead of waiting for his usual pharmacy to reopen the next business day. This innocent action circumvented the safety system, which did not extend to the other pharmacy. Some pharmacy chains have databases integrated across multiple sites, which can help if patients stay loyal to one chain.