AB0292 EFFECTS OF ACETAMINOPHEN ON THE KIDNEY FUNCTIONS OF PAITIENTS WITH MUSCULOSKERLTAL DISEASE TREATED WITH LONG-TERM NONSTEROIDAL ANTI-INFRAMMATORY DRUG THERAPY
Authors: Toshiaki Aizawa, Tetsuya Kawano, Takeshi Kashiwagura, Naohisa Miyakoshi, Yoichi Shimada
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> While nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequently used therapeutic agents, they are known to cause side effects, such as gastrointestinal disorders and kidney dysfunction. As the proportion of patients with chronic kidney disease (CKD) increases with age, dealing with NSAIDs requires particular care in areas with aging populations. However, in many cases, prescriptions are continued without any particular plan. Hence, the effects of acetaminophen (AAP), which does not cause kidney dysfunction, are being revisited. Opportunities are increasing for using formulations containing tramadol hydrochloride in patients with chronic pain or intravenous agents for perioperative pain management. <h3>Objectives</h3> In this study, we investigated the kidney functions of patients with musculoskeletal disease who had been using NSAIDs for a long time and examined the possibility of switching to AAP. <h3>Methods</h3> The subjects were 105 patients with musculoskeletal disease (42 men and 63 women) who were being treated as outpatients in the orthopedics department of our hospital and had been using NSAIDs for at least 3 months. They primarily had 5 musculoskeletal diseases, including degenerative osteoarthritis (OA), rheumatoid arthritis (RA), osteoporosis (OP), polymyalgia rheumatica (PMR), and gout (G). After checking their background characteristics, we measured their kidney functions and visual analogue scale (VAS) scores, and then switched them from NSAIDs to AAP. Kidney functions were evaluated by classifying CKD using glomerular filtration rate (eGFR) and urinary protein, and by using the Cockcroft-Gault equation to calculate creatinine clearance (Ccr). The patients were given the NSAIDs that they had been taking for single use. Six months after the switch, we remeasured their kidney functions and VAS scores, and investigated whether they could continue using AAP and whether they had used NSAIDs. <h3>Results</h3> The patients' mean age at the time of switching from NSAIDs to AAP was 76 years, and their mean duration of NSAID use was 43 months. For the diseases, 63 patients had OA, 20 had RA, 14 had OP, 6 had PMR, and 2 had G. Before the switch, the mean VAS score was 41.6 mm and mean eGFR was 67.0 mL/min/1.73 m<sup>2</sup>. On the basis of the eGFR, the CKD classification was G3 or higher in 38.1% of patients. The CKD classifications with the amounts of urinary protein added to the eGFR were as follows: green, 44.7%; yellow, 33.0%; orange, 14.6%; and red, 7.8%, with 55.4% classified as having CKD. By age, the proportions of patients with CKD based on eGFR and CKD classification were as follows, respectively: 0.0% and 12.5% for those in their 50s, 16.7% and 25.0% for those in their 60s, 29.3% and 48.8% for those in their 70s, and 59.5% and 69.0% for those in their 80s and older. The mean AAP dose was 455 mg. Six months after the switch, 69 patients had continuously used AAP without regular NSAID use. Of these patients, 13 had used NSAIDs for rescue purposes. Thirty-six patients had stopped using AAP, the most common reason being ineffectiveness (15 patients), although 9 patients did so because they no longer needed any analgesic. Three patients stopped using the drug owing to palpitations or other side effects, although none stopped because of liver dysfunction. Overall, the mean VAS score declined significantly as compared with before the switch, as did the mean eGFR. Of those who continued to use AAP, 56 patients who did not use any NSAIDs exhibited significantly lower mean VAS scores, but not a significant decline in mean eGFR. <h3>Conclusion</h3> The proportion of patients with CKD who were receiving long-term NSAID therapy was higher than that of the general population for all age groups. Halting NSAIDs and switching to AAP could help maintain kidney functions, which could continue to decline with NSAID use. <h3>References</h3> [1] CKD guidebook;2012 <h3>Disclosure of Interests</h3> None declared