A Case of Mistaken Identity?
The husband of PC, a 55-year-old woman, comes into the pharmacy to pick up a prescription for his wife. He tells the pharmacist that PC has a kidney stone and may need to have surgery in a few weeks. The pharmacist retrieves a prescription ready for PC for tamsulosin (Flomax) 0.4 mg daily. The husband immediately exclaims, “You must have made a mistake!” He explains that he has been taking tamsulosin for years to treat his enlarged prostate. How should the pharmacist respond?
SK is a 62-year-old Caucasian man admitted to the hospital for a painful gout flare. He complains of 6 years of joint pain, loss of motion, and tophi (deposits of urate crystals). Upon laboratory evaluation, he is found to have a serum uric acid level of 9 mg/dL. SK has failed adequate trials of the xanthine oxidase inhibitors allopurinol (Zyloprim) and febuxostat (Uloric). SK’s doctor asks the pharmacist if there are any other pharmacologic options available to SK that are likely to be successful. How should the pharmacist respond?
Answer: Case One
As an alpha1-adrenergic receptor antagonist, tamsulosin causes relaxation of the smooth muscles of the prostate, ureter, and bladder neck. PC’s husband is correct that tamsulosin is FDA approved for the treatment of an enlarged prostate (benign prostatic hyperplasia). However, multiple studies in urology literature have found that alpha1-antagonists are useful in the management of kidney stones as well. They have been shown to increase the chances of and shorten the duration to spontaneous stone expulsion.
Although it would not be unreasonable for the pharmacist to verify the prescription’s correctness, the pharmacist should explain to PC’s husband that it is not improper for tamsulosin to be used to promote the passage of kidney stones. Dr. Coleman is an associate professor of pharmacy practice and director of the pharmacoeconomics and outcomes studies group at the University of Connecticut School of Pharmacy. Ms. Baczek is a PharmD candidate at the University of Connecticut School of Pharmacy.
Answer: Case Two
In September 2010, the FDA approved pegloticase (Krystexxa), a novel agent for the treatment of chronic gout in adult patients refractory to conventional gout treatment. Pegloticase is a pegylated, recombinant urate oxidase (uricase) that catalyzes the oxidation of uric acid to allantoin, thus reducing uric acid levels.
SK’s gout can be categorized as refractory due to his inadequately controlled gout symptoms and failure to achieve normal serum uric acid levels (<6 mg/dL) despite adequate trials of conventional therapy. Consequently, he is a candidate for pegloticase.
If pegloticase is to be initiated, the pharmacist should inform the doctor that the recommended dose is 8 mg every 2 weeks (total treatment duration is not well established) infused intravenously over a minimum of 2 hours. The pharmacist should recommend premedication with antihistamines and corticosteroids to prevent anaphylaxis and infusion reactions. To prevent a gout flare, nonsteroidal anti-inflammatory drugs or colchicine (Colcrys) should be started at least 1 week before initiation of therapy and continued for at least 6 months unless contraindicated or not tolerated.
Craig I. Coleman, PharmD, and Victoria L. Baczek, PharmD Candidate