Beta-Blockers, Trimethoprim-Sulfamethoxazole, and the Risk of Hyperkalemia Requiring Hospitalization in the Elderly

Abstract

Background and objectives:The simultaneous use of beta adrenergic receptor blockers (␤-blockers) and trimethoprimsulfamethoxazole (TMP-SMX) may confer a high risk of hyperkalemia.Design, setting, participants, & measurements: Two nested case-control studies were conducted to examine the association between hospitalization for hyperkalemia and the use of TMP-SMX in older patients receiving ␤-blockers. Linked health administrative records from Ontario, Canada, were used to assemble a cohort of 299,749 ␤-blockers users, aged 66 years or older and capture data regarding medication use and hospital admissions for hyperkalemia.Results: Over the study period from 1994 to 2008, 189 patients in this cohort were hospitalized for hyperkalemia within 14 days of receiving a study antibiotic. Compared with amoxicillin, the use of TMP-SMX was associated with a substantially greater risk of hyperkalemia requiring hospital admission (adjusted odds ratio, 5.1; 95% confidence interval [CI], 2.8 to 9.4). No such risk was identified with ciprofloxacin, norfloxacin, or nitrofurantoin. When dosing was considered, the association was greater at higher doses of TMP-SMX. When the primary analysis was repeated in a cohort of non-␤-blocker users, the risk of hyperkalemia comparing TMP-SMX to amoxicillin was not significantly different from that found among ␤-blocker users.Conclusions: Although TMP-SMX is associated with an increased risk of hyperkalemia in older adults, these findings show no added risk when used in combination with ␤-blockers.

Death Following Recreational Use of Designer Drug “Bath Salts” Containing 3,4-Methylenedioxypyrovalerone (MDPV)

“…Trimethoprim is not reported to cause stimulant effects with chronic use or in acute overdose. There are reports of hyperkalemia occurring in patients predisposed to potassium retention (underlying renal failure or concurrent diuretic use) [24,25]. Our patient was not known to be taking a trimethoprim-containing medication, and personal communication with the laboratory performing the test (telephone correspondence with Dr. S. Kacinko, NMS Labs, August 2011) revealed an additional case where MDPV and trimethoprim were found together using similar testing methods.…”

Risk of End-Stage Renal Disease and Death After Cardiovascular Events in Chronic Kidney Disease

“…The primary end point of ESRD defined as the initiation of renal replacement therapy, rather than as a drop of the GFR below a given threshold, has the advantage of being the most clinically relevant outcome in areas where practice patterns are similar to our own. Moreover, the low emigration rate in Ontario of <1.0%/yr 36,37 and the provincial scope of outcome capture minimized ascertainment bias in our cohort. As previously noted, potential biases resulting from referral patterns were less likely in our cohort of patients because of the singlepayer nature of the healthcare system in Ontario 12 Our analysis has several limitations.…”

Effects of Funding Policy Changes and Health Warnings on the Use of Erythropoiesis-Stimulating Agents

“…These databases are anonymously linked using 10-digit health card numbers and are routinely used to investigate drug safety in Ontario. [11][12][13][14] This study was approved by the ethics review board of Sunnybrook Health Sciences Centre, Toronto.…”