Methemoglobinemia and Anemia Caused by Pyridium Overuse in an Adult

Abstract

SESSION TITLE: Poisoning and Drug Overdose 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Chronic pyridium misuse can lead to acute hypoxia due to methemoglobinemia and anemia. CASE PRESENTATION: A 23 y/o F with Schwachman-Diamond Syndrome (SDS) and autism presented with progressively worsening shortness of breath and a Hg of 6.2 g/dL. She has a h/o chronic abdominal pain, vaginitis, and recurrent UTIs from decreased mucosal secretions related to her SDS. She denied fevers, chills, or cough. She was hypoxic to 83% on room air with sinus tachycardia. She was not in any distress, but her lips were cyanotic. Lungs were clear to auscultation bilaterally. CXR was unremarkable. She received 2 U prbcs and was placed on a NRB at 100% with no improvement in saturations. ABG showed pH 7.43, pCO2 27, PO2 267 with 72% sats and a methemoglobin (MetHb) of 25.8%. She received 10 mL of IV methylene blue with improvement in her sats to 92% on a NRB. Repeat ABG three hours later showed pH 7.47, pCO2 26, PO2 339 w/ 94% sats and MetHb of 4.7%. Within the next 12 hrs she was weaned to nasal cannula and had a MetHb of 2.6%. LDH was 2295 U/L, haptoglobin was undetectable, and Coombs test was negative, suggesting a non-immune hemolytic anemia. She was taking pyridium 200 mg PO up to seven times a day over the past few days for frequent dysuria. DISCUSSION: Pyridium is an oral urinary tract analgesic given for symptomatic relief of dysuria (Haigh and Dewar 2006). It has been shown to cause hemolytic anemia and acquired methemoglobinemia via its metabolite aniline (Jeffery et al. 1982). It most commonly occurs in infants and children due to weight-based dosing and in adults with decreased renal function. In an effort to refrain from unnecessary antibiotic use due to frequent UTIs, she was given pyridium to alleviate her dysuria. Although she had normal renal function, her methemoglobinemia was likely due to toxicity from overuse as she was taking twice the recommended amount of 200 mg po TID. With an emphasis on meaningful use in regards to antibiotic administration, physicians are becoming more likely to recommend symptomatic management. With the availability of pyridium over the counter, this may result in a higher incidence of these findings than previously reported. CONCLUSIONS: Methemoglobinemia and anemia can develop from pyridium misuse in adults. Reference #1: Haigh, C. and J.C. Dewar (2005). Multiple adverse effects of pyridium: a case report. Southern Medical Association. 99 (1): 90-92. Reference #2: Jeffery, W.H., Zelicoff, A.P, and W.R. Hardy (1982). Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intelligence and Clinical Pharmacy. 16: 157-159. DISCLOSURE: The following authors have nothing to disclose: Crystal Duran, Ellora Jalali No Product/Research Disclosure Information