-
Journal of Infection and Chemotherapy :... Dec 2013Nitrofurantoin and phenazopyridine are two drugs commonly used against urinary tract infections. Both compounds exert oxidative damage in patients deficient in...
Nitrofurantoin and phenazopyridine are two drugs commonly used against urinary tract infections. Both compounds exert oxidative damage in patients deficient in glucose-6-phosphate dehydrogenase. This study was done to assess the interactions of these drugs with the soxRS regulon of Escherichia coli, a superoxide-defense system (that includes a nitroreductase that yields the active metabolite of nitrofurantoin) involved in antibiotic multi-resistance. The effects of either nitrofurantoin or phenazopyridine, upon strains with different soxRS genotypes, were measured as minimum inhibitory concentrations (MICs) and growth curves. Also, the ability of these drugs to induce the expression of a soxS'::lacZ gene fusion was assessed. The effect of antibiotics in the presence of phenazopyridine, paraquat (a known soxRS inducer), or an efflux inhibitor, was measured using the disk diffusion method. A strain constitutively expressing the soxRS regulon was slightly more susceptible to nitrofurantoin, and more resistant to phenazopyridine, compared to wild-type and soxRS-deleted strains, during early treatment, but 24-h MICs were the same (8 mg/l nitrofurantoin, 1,000 mg/l phenazopyridine) for all strains. Both compounds were capable of inducing the expression of a soxS'::lacZ fusion, but less than paraquat. Subinhibitory concentrations of phenazopyridine increased the antimicrobial effect of ampicillin, chloramphenicol, tetracycline, and nitrofurantoin. The induction or constitutive expression of the soxRS regulon seems to be a disadvantage for E. coli during nitrofurantoin exposure; but might be an advantage during phenazopyridine exposure, indicating that the latter compound could act as a selective pressure for mutations related to virulence and antibiotic multi-resistance.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Proteins; Genotype; Microbial Sensitivity Tests; Nitrofurantoin; Phenazopyridine; Regulon; Trans-Activators; Transcription Factors
PubMed: 23793794
DOI: 10.1007/s10156-013-0635-4 -
The Journal of Emergency Medicine Aug 2021Sulfhemoglobinemia is a rare dyshemoglobinemia that presents similarly to methemoglobinemia.
BACKGROUND
Sulfhemoglobinemia is a rare dyshemoglobinemia that presents similarly to methemoglobinemia.
CASE REPORT
An 83-year-old woman with stage IV ovarian cancer presented to the Emergency Department after a near syncopal spell and was found to be cyanotic with a pulse oximetry reading of 71%. Pulse oximetry improved to only the mid-80s range with administration of high-flow oxygen. Her arterial blood gas on supplemental high-flow oxygen demonstrated a PaO of 413 mm Hg and methemoglobin of 1.2%, but also noted the interference of the co-oximetry with sulfhemoglobinemia. Further history revealed that the patient had recently been started on phenazopyridine. The phenazopyridine was stopped, an exchange transfusion was offered but declined, and the patient was discharged to home hospice. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The diagnosis of sulfhemoglobinemia can be challenging given that routine co-oximetry does not identify it. The clue to the diagnosis is that the cyanotic-appearing patient has a normal or elevated PaO and seems to be less ill than expected, given the degree of cyanosis. Sulfhemoglobinemia does not reverse with the administration of methylene blue.
Topics: Aged, 80 and over; Cyanosis; Dyspnea; Female; Humans; Methemoglobinemia; Methylene Blue; Oximetry; Phenazopyridine; Sulfhemoglobinemia
PubMed: 34034895
DOI: 10.1016/j.jemermed.2021.03.002 -
JAMA Jun 1979
Topics: Acute Kidney Injury; Aminopyridines; Humans; Phenazopyridine
PubMed: 448835
DOI: No ID Found -
Obstetrics and Gynecology Aug 2016To evaluate the usefulness of phenazopyridine for confirmation of ureteral patency during intraoperative cystoscopy. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To evaluate the usefulness of phenazopyridine for confirmation of ureteral patency during intraoperative cystoscopy.
METHODS
We conducted a randomized controlled trial comparing use of phenazopyridine with no medications for evaluation of ureteral patency during intraoperative cystoscopy in women undergoing pelvic surgery. The primary study outcome was time to visualize ureteral urine efflux. To detect a 3-minute difference with α of 0.05 using a two-sided, two-sample t test and β 0.80 required 98 patients equally divided into two groups.
RESULTS
A total of 104 women were randomized from April to December 2015. Patients in the treatment group tended to be older (P=.02); otherwise, study groups were similar. Time to visualize ureteral urine efflux did not differ between study groups with a mean time of 2 minutes 40 seconds (±2 minutes 38 seconds) in the control group and 2 minutes 53 seconds (±4 minutes 35 seconds) in the treatment group (P=.77). Regarding the surgeon survey, surgeons felt less frustrated and impatient in visualization of ureteral urine efflux in the treatment group compared with the control group (mean response 1.5±0.8 in treatment compared with 2.0±1.0 in control, P=.007), and surgeons felt that the cystoscopy took too long more often in the control than in the treatment group (1.7±0.9 in treatment compared with 2.1±1.0 in control, P=.02). Trial of void result differed significantly between groups with fewer patients in the treatment group failing a void trial (P=.04). There were no adverse events related to phenazopyridine use.
CONCLUSION
Preoperative phenazopyridine is a useful and cost-saving medication for use in planned cystoscopy for evaluation of ureteral patency.
CLINICAL TRIAL REGISTRATION
ClinicalTrials.gov, https://clinicaltrials.gov/, NCT02424149.
Topics: Adult; Aged; Aged, 80 and over; Attitude of Health Personnel; Coloring Agents; Cystoscopy; Female; Gynecologic Surgical Procedures; Humans; Intraoperative Care; Intraoperative Complications; Middle Aged; Phenazopyridine; Time Factors; Ureter; Wounds and Injuries
PubMed: 27399998
DOI: 10.1097/AOG.0000000000001472 -
American Journal of Obstetrics and... Mar 2011We sought to determine if phenazopyridine improves pain in catheterized patients recovering from gynecologic surgery. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
We sought to determine if phenazopyridine improves pain in catheterized patients recovering from gynecologic surgery.
STUDY DESIGN
This trial randomized 240 adult women, who were undergoing gynecologic surgery and requiring an indwelling Foley catheter, to placebo or phenazopyridine hydrochloride. Group assignment was masked by instillation of orange dye in the Foley bag of both groups. The primary outcome was the mean postoperative visual analog score (VAS). Secondary outcomes were pain medicine utilization and blinding efficacy.
RESULTS
In all, 219 patients received study medications (112 phenazopyridine and 107 placebo). There was no significant difference in demographics, procedure type, bladder VAS, overall VAS, and pain medication use. Only 25 of the 45 participants who responded guessed their group assignment correctly, suggesting adequate blinding.
CONCLUSION
Postoperative VAS scores and pain medicine usage did not change with using routine phenazopyridine following gynecology surgery. Colored dye adequately masks visual side effects of phenazopyridine.
Topics: Anesthetics, Local; Female; Gynecologic Surgical Procedures; Humans; Middle Aged; Pain; Phenazopyridine; Urinary Catheterization
PubMed: 21376167
DOI: 10.1016/j.ajog.2010.12.045 -
Hematology Reports May 2023Methemoglobinemia is an acute medical emergency that requires prompt correction. Physicians should have a high degree of suspicion of methemoglobinemia in cases that...
Phenazopyridine-Induced Methemoglobinemia in a Jehovah's Witness Treated with High-Dose Ascorbic Acid Due to Methylene Blue Contradictions: A Case Report and Review of the Literature.
Methemoglobinemia is an acute medical emergency that requires prompt correction. Physicians should have a high degree of suspicion of methemoglobinemia in cases that present with hypoxemia that does not resolve with supplemental oxygenation, and they should confirm this suspicion with a positive methemoglobin concentration on arterial blood gas. There are multiple medications that can induce methemoglobinemia, such as local anesthetics, antimalarials, and dapsone. Phenazopyridine is an azo dye used over-the-counter as a urinary analgesic for women with urinary tract infections, and it has also been implicated in causing methemoglobinemia. The preferred treatment of methemoglobinemia is methylene blue, but its use is contraindicated for patients with glucose-6-phosphatase deficiency or those who take serotonergic drugs. Alternative treatments include high-dose ascorbic acid, exchange transfusion therapy, and hyperbaric oxygenation. The authors report a case of a 39-year-old female who took phenazopyridine for 2 weeks to treat dysuria from a urinary tract infection and subsequently developed methemoglobinemia. The patient had contraindications for the use of methylene blue and was therefore treated with high-dose ascorbic acid. The authors hope that this interesting case promotes further research into the utilization of high-dose ascorbic acid for managing methemoglobinemia in patients who are unable to receive methylene blue.
PubMed: 37367083
DOI: 10.3390/hematolrep15020034 -
Journal of Clinical Pharmacology Feb 1996Acquired methemoglobinemia may be produced by the ingestion or absorption of certain chemicals and xenobiotics. A case of methemoglobinemia in an 8.5-month old infant... (Review)
Review
Acquired methemoglobinemia may be produced by the ingestion or absorption of certain chemicals and xenobiotics. A case of methemoglobinemia in an 8.5-month old infant who ingested approximately 227 mg/kg of phenazopyridine is presented. Although this adverse event is often reversed with a single dose of methylene blue, this patient required three doses of methylene blue (1 mg/kg) over a 25-hour period. It is suggested that the need for repeated doses of methylene blue in this case was not only related to the large dose of phenazopyridine, but also its metabolites (i.e., aniline), which have the potential to produce methemoglobinemia. This case illustrates the need for close observation and serial monitoring of methemoglobin levels in patients who are at increased risk for the development of protracted methemoglobinemia. Integration of knowledge of developmental pharmacology, drug metabolism, and pharmacodynamic properties are critical determinants in the evaluation and treatment of patients with drug-induced methemoglobinemia.
Topics: Adolescent; Anesthetics, Local; Antidotes; Drug Overdose; Humans; Infant; Methemoglobin; Methemoglobinemia; Methylene Blue; Phenazopyridine
PubMed: 8852386
DOI: 10.1002/j.1552-4604.1996.tb04175.x -
Report on Carcinogens : Carcinogen... 2004
Topics: Analgesics; Animals; Carcinogenicity Tests; Carcinogens; Female; Government Regulation; Guidelines as Topic; Humans; Male; Mice; Models, Biological; Occupational Exposure; Phenazopyridine; Rats; United States
PubMed: 21089943
DOI: No ID Found -
Report on Carcinogens : Carcinogen... 2002
Topics: Animals; Carcinogens; Environmental Exposure; Government Regulation; Humans; Phenazopyridine; United States
PubMed: 15332289
DOI: No ID Found -
Journal of the American Geriatrics... Dec 2014
Topics: Aged, 80 and over; Anemia, Hemolytic; Diabetes Complications; Humans; Kidney Failure, Chronic; Male; Phenazopyridine
PubMed: 25516057
DOI: 10.1111/jgs.13161