Case of drug-induced kidney stone from overuse of phenazopyridine.

Drug-induced nephrolithiasis represents only 1%-2% of stone cases. Here we focus on drugs capable of crystallizing and forming stone, specifically phenazopyridine (Pyridium/Azo). This is a case of a patient who presented with a stone conglomerate in the right proximal ureter and underwent definitive treatment. Interestingly, the stone had a purple hue with FTIR spectroscopy showing stone composition of calcium oxalate (monohydrate and dihydrate) and a material resembling phenazopyridine. We retrospectively learned that she used multiple extended courses of phenazopyridine over 3 months.

A Case That Will Take Your Breath Away: Acquired Methemoglobinemia Related to Trimethoprim-Sulfamethoxazole and Phenazopyridine Ingestion for Treatment of Urinary Tract Infection.

Trimethoprim-sulfamethoxazole (TMP-SMX) and phenazopyridine are individually associated with methemoglobinemia through a series of altered reduction-oxidation reactions. We report a case of methemoglobinemia associated with concurrent use of TMP/SMX and phenazopyridine in a 70-year-old woman with recurrent urinary tract infections. She presented to the emergency department for worsening back pain in the setting of recurrent urinary tract infections, concerning for pyelonephritis. During her workup, she became acutely hypoxic. The emergency department provider suspected the presence of abnormal hemoglobin. An arterial blood gas showing elevated levels of methemoglobinemia confirmed the suspicion. The combined use of TMP/SMX and phenazopyridine was thought to be the likely etiology of hypoxia. This case highlights the importance of medication management in the geriatric population, as well as the judicious use of antibiotics for urinary tract infections-a common chief complaint in the primary care setting.

Skin ulcers as a complication of short-term use of phenazopyridine in an old man: A case report.

INTRODUCTION: Phenazopyridine is an azo dye, which exerts local anesthetic or analgesic action on urinary tract mucosa through an unknown mechanism. Besides its common complications including orange discoloration of the urine and gastrointestinal problems, it may have rare side effects like hemolytic anaemia, methemoglobinemia, renal failure, and skin changes. We reported a paraplegic man with skin ulcers on scretom and right foot after about 3 days of phenazopyridine use CASE REPORT: A 62-year-old man presented with flesh shaped deep ulcers in lower parts of the body. He declared that at first a bluish discoloration was developed in the lower extremities and scrotum skin after use of eight phenazopyridine tablets (200 mg) and then these lesions turned to blisters and ulcers and they were prurient. The patient underwent sonography and CT-angiography; however, no pathologic findings were found. He just received losartan for many years as past drug history. According to the history, a delayed drug hypersensitivity reaction was suspected and the patient wounds healed after using special type of dressings and antibiotic therapy regarding positive wound cultures. CONCLUSION: Phenazopyridine severe skin changes are hardly reported. We described a case who experienced severe skin reactions and ulcers following phenazopyridine use not related to other complications including renal dysfunction, methemoglobinemia, and hemolytic anemia.

Safety analysis of long-term phenazopyridine use for radiation cystitis.

BACKGROUND: Phenazopyridine is a urinary tract analgesic indicated for short-term treatment of irritation in the lower urinary tract. Despite the lack of evidence for extended use, it is often used in varying durations for supportive care for cancer patients with radiation-induced cystitis. The objective of this study was to compare the incidence of adverse drug reactions in patients with radiation cystitis receiving long-term phenazopyridine (>14-day supply) compared to a matched comparator group. METHODS: This retrospective cohort study compared adverse events among cancer patients with and without phenazopyridine exposure. Included patients received radiation and at least one chronic medication between 1 July 2008 and 30 June 2017. The phenazopyridine group also received >14-day supply of phenazopyridine during the study period. Patients were matched based on gender, age (±5 years), cancer diagnosis, and palliative or curative treatment intent. Data collection occurred at baseline, during the time of presumed exposure, and through the end of the study period for surveillance purposes. RESULTS: A total of 272 patients received phenazopyridine for >14-day supply during the study period. Of these, 90 patients were included and matched to an equal number of patients in the comparator group. The included patients were similar between groups and were largely male with a diagnosis of prostate cancer. Most patients received between a 30- and 60-day supply of phenazopyridine. There were a total of 13 adverse drug reactions in the phenazopyridine group and 18 in the comparator group (p = 0.32). No differences were identified between the phenazopyridine and comparator groups for the incidence of individual adverse drug reactions, emergency department visits, hospitalizations, or new diagnoses of hepatocellular or colorectal cancer. CONCLUSION: There was no difference in adverse drug reactions among patients receiving phenazopyridine for >14 days compared to a matched comparator group. The overall incidence of adverse events in both groups was low.

Perioperative Hypoxia Secondary to Phenazopyridine-induced Methemoglobinemia in an Adolescent Patient Without Renal Insufficiency or Overdose: An Unusual Case.

Phenazopyridine is a common, well-tolerated medication with minimal side effects. Severe side effects are rare and include methemoglobinemia in setting of overdose, elderly patients, renal insufficiency, and chronic use. Here, we report a case of methemoglobinemia-induced perioperative hypoxia in an adolescent patient without renal insufficiency or overdose which has not been reported previously. This case underscores the importance of judicious use of this medication in all patients but notably in pediatric patients and those with chronic lung disease.

Pyelonephritis following phenazopyridine use.

We present a case of pyelonephritis following the extended andsolitary use of over-the-counter phenazopyridine in a forty-year-oldfemale. The patient initially had uncomplicated cystitis signs andsymptoms which partially resolved with phenazopyridine and therefore she continued use. She presented to the emergency department with systemicsigns and symptoms of acute pyelonephritis. As phenazopyridine is devoidof antibacterial properties this allowed the lower urinary tractinfection to progress to acute pyelonephritis requiring intravenousantibiotics. Better patient education may preclude this complication.

Intraoperative Cystoscopic Evaluation of Ureteral Patency: A Randomized Controlled Trial.

OBJECTIVE: To compare different modalities to aid in the evaluation of intraoperative ureteral patency on cystoscopy in the postindigo carmine era. METHODS: In a randomized controlled trial, participants undergoing pelvic surgery were randomized into one of four groups: saline distention (control), 10% dextrose distention, oral phenazopyridine, or intravenous sodium fluorescein. Our primary outcome was visibility of the ureteral jets. Secondary outcomes included surgeon satisfaction; adverse reactions including allergies, urinary tract infections, urinary retention, cystoscopy times, and ureteral obstruction; and delayed diagnosis. Participants were followed for 6 weeks. A sample size of 176 participants was planned to demonstrate a 30% difference in the visibility scale. All analyses were performed in an intention-to-treat fashion. RESULTS: From February 25, 2015, through August 2015, 176 participants were enrolled; 174 completed the trial, and two did not undergo intervention. Forty-four participants were included in the phenazopyridine, dextrose, saline, and sodium fluorescein groups. Sodium fluorescein and 10% dextrose resulted in significantly improved visibility and satisfaction when compared with the control group (P<.001 and P=.004, respectively). Dextrose provided the highest satisfaction and phenazopyridine provided lowest, but visibility was not statistically different between the two groups (P=.101). Three ureteral obstructions were identified intraoperatively and none in the postoperative period. Mean total cystoscopy time varied between 4.0 and 4.8 minutes and postoperative urinary retention rate was 50% across all groups. Overall urinary tract infection rate was 24.1%, which was similar between interventions. There were no related adverse events. CONCLUSION: Compared with the control, 10% dextrose and sodium fluorescein resulted in improved visibility and provided significantly more satisfaction in the evaluation for ureteral patency with no considerable increase in operative time or morbidity. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT02476448.

Troponin leak associated with drug-induced methemoglobinemia.

Drug-induced methemoglobinemia is a well-described entity but has not been previously associated with elevated troponins in the absence of cardiac symptoms. We report a case of a patient presenting to the emergency department (ED) with complaints related to an exacerbation of her long-standing cystitis. A low pulse oximetry reading prompted an evaluation, revealing a troponin leak, which peaked at 10 hours. Her methemoglobin level was found to be elevated at 11.4%, but a preexisting anemia apparently prevented the clinical recognition of cyanosis. The methemoglobinemia was determined to be secondary to her ingestion of phenazopyridine and trimethoprim-sulfa methoxizole. Although phenazopyridine and sulfa agents have long been known to cause methemoglobinemia, our patient exhibited an asymptomatic troponin leak that has not been previously reported as a complication of drug-induced methemoglobinemia. Clinicians should be aware of this potential association.

Phenazopyridine associated acute interstitial nephritis and review of literature.

Phenazopyridine is a urinary analgesic; commonly seen side-effects of this drug include, orange discoloration of urine, methemoglobinemia, yellowish skin discoloration, hepatitis and acute renal failure. Various case reports with phenazopyridine associated acute renal failure secondary to acute tubular necrosis have been reported in the literature. Acute kidney injury in these patients is caused by either direct injury to renal tubular epithelial cells or secondary to pigment induced nephropathy from hemolytic anemia. Hypoxic injury from phenazopyridine-induced methemoglobinemia has been well documented. We report a case of biopsy proven acute interstitial nephritis, associated with therapeutic doses of phenazopyridine without any evidence of methemoglobinemia or other mechanism of renal injury. Clinicians should be aware of the toxicity of this commonly used drug and should look closely for signs of renal insufficiency. Identifying and stopping the offending medication stays as the first step, but recent studies indicate that early steroid administration improves renal recovery, as well as decreasing the risk of progression to chronic kidney disease with fibrosis and consequent permanent renal damage.

Acquired methaemoglobinaemia related to phenazopyridine ingestion.

Methaemoglobin is an altered state of haemoglobin in which the ferrous ions of haeme are oxidised to the ferric state. This results in increased affinity to the bound oxygen and decreasing its availability to tissues. Most cases of methaemoglobinaemia are acquired, resulting from an increased methaemoglobin formation by various exogenous agents. The authors report an elderly patient presenting to the emergency department with a 1-month history of shortness of breath. Around the same time she had started using over-the-counter (OTC) phenazopyridine tablets for urinary symptoms. The patient was hypoxic and cyanotic; however, lacked evidence of hypoxaemia on the arterial blood gas. The presence of abnormal haemoglobin was suspected and confirmed by elevated levels of methaemoglobin. Phenazopyridine was proposed to be the likely aetiology of the methaemoglobinaemia, which the patient was not aware of. This case highlights the importance of always inquiring the OTC drug use especially in geriatric population.

Acrocyanosis from phenazopyridine-induced sulfhemoglobinemia mistaken for Raynaud phenomenon.

Rheumatologists are often asked to evaluate patients with Raynaud phenomenon. Occasionally, an alternate explanation is revealed such as acrocyanosis. Methemoglobinemia and sulfhemoglobinemia are rare causes of cyanosis that can be medication-induced. Both are known complications of therapy with phenazopyridine. We report an unusual case of a 45-year-old woman in whom sulfhemoglobinemia from chronic therapy with phenazopyridine was misdiagnosed as due to Raynaud phenomenon and limited scleroderma. This case illustrates the importance of taking into account medication-related adverse events when evaluating patients with Raynaud-like phenomenon.