Study of Phenazopyridine - Term Paper Example

?Phenazopyridine I. Introduction The official information websites of the United s National Institutes of Health (NIH) treat phenazopyridine andphenazopyridine HCL as identical drugs. For example, when one searches for “phenazopyridine” in MedlinePlus, an official website of the NIH, the output items from the search will include “Phenazopyridine HCL.” Similarly, if one searches for “phenazopyridine” in DailyMed, another information website of the NIH, the search output items also include phenazopyridine HCL. In this work, we rely more on information released by the US NIH, being the pool of medical experts and the leading medical authority in the United States. Of course, we also refer to the medical journals on the drug. The NIH, through the U.S. National Library of Medicine, informs that phenazopyridine is often prescribed because it “relieves urinary pain, burning, irritation, and discomfort, as well as urgent and frequent urination caused by urinary tract infections, surgery, or examination procedures” (“Phenazopyridine,” first paragraph). Further, the NIH said that “Phenazopyridine HCL is indicated for the symptomatic relief of pain, burning, urgency, frequency, and other discomforts arising from irritation of the mucosa of the lower urinary tract caused by infection, trauma, surgery, endoscopic procedures, or the passage of sounds or catheter” (“Phenazopyridine HCL” 1). The NIH emphasized that phenazopyridine is not a cure for infection and it is not an antibiotic (“Phenazopyridine,” first paragraph). However, the NIH recognizes that the drug is “sometimes prescribed for other uses” but the NIH did not identify the other medical uses of the phenazopyridine (“Phenazopyridine,” 2nd paragraph). Nevertheless, the work of Hui and others indicate that phenazopyridine HCL is used “to facilitate intraoperative confirmation of ureteric patency” and is a low-cost approach for the procedure (Hui et al. 845). The NIH narrated that phenazopyridine HCL is “reddish-brown, odorless, slightly bitter, crystalline powder” (“Phenazopyridine HCL” 1). The NIH also reported that phenazopyridine HCL “has a specific analgesic effect in the urinary tract, promptly relieving burning and pain.” The NIH provided the “structural formula” of phenazopyridine HCL as . In describing the clinical pharmacology of phenazopyridine HCL and writing only recently in September 2010, the NIH narrated that “phenazopyridine hydrochloride is excreted in the urine where it exerts a topical analgesic effect on the pain, burning, urgency, and frequency” but “the precise mechanism of the action is unknown” (“Phenazopyridine HCL” 1). Pharmacology refers to the study of drugs and their effects on living organisms (Roach 1). The NIH strongly recommended that administration of phenazopyridine should not delay diagnosis and the treatment of the cause of the body discomfort, condition, illness, or infection (“Phenazopyridine HCL” 1). The NIH recommends the drug for only a symptomatic relief of pain and not as a substitute for curing the illness or condition (“Phenazopyridine HCL” 1). Most important, the NIH emphasized that the drug should not be used as a substitute for “specific surgery” and antimicrobial therapy (“Phenazopyridine HCL” 1). The work of Patricia Duffield has identified the drug as for “pain control only” with antibiotic therapy in addressing urinary tract infection (16c). The September 2010 document of the NIH stressed that co-treatment of urinary tract infection with phenazopyridine “should not exceed 2 days” and stressed that “there is no evidence that the combined administration of phenazopyridine and an antimicrobial provides greater benefit than administration of the antimicrobial alone after 2 days” (“Phenazopyridine HCL” 1). II. Pharmacokinetics of Phenazopyridine Pharmacokinetics describes the actions within the body upon the administration of a drug (Roach 6). Unfortunately, however, in the September 2010 material of the NIH that has been posted as of November 2011, the NIH revealed that the pharmacokinetic properties of phenazopyridine hydrochloride “have not been determined” (“Phenazopyridine HCL” 1). However, a few materials revealed additional information and the information web pages of the NIH reveal additional information on the pharmacokinetics of phenazopyridine. Absorption. The human body absorbs phenazopyridine from the gastrointestinal tract (Hiren et al., 106). One hour after the oral ingestion of phenazopyridine, the urine acquires an orange tint (Hui et al. 846). This indicates fast absorption. Excretion. According to the NIH, phenazopyridine and its “metabolites” are rapidly expelled by the kidneys (“Phenazopyridine HCL” 1). Further, according to the NIH, among health subjects, “90% of the 600 mg/day dose of phenazopyridine hydrocholoride was expelled in the urine in 24 hours, 41% as unchanged drug and 49% as metabolites” (“Phenazopyridine HCL” 1). Thus, data on the phenazopyridine indicates not only fast absorption but also relatively fast excretion by the body. Distribution. Based on the accounts of immediately available literature, phenazopyridine is distributed to many parts of the body based on the stains the drug makes the patient’s contact lenses, indicating that the stain affects at least some of the patient’s body fluids. This indicates that the drug is extensively distributed in the body through the body fluids. The datum that phenazopyridine stains clothes also indicate that phenazopyridine is also distributed in the body tissues. Storage. Based on the speed of excretion of phenazopyridine from the body, it appears that the drug is not stored permanently in the human body. Or, at least, there is no research or immediately available literature that makes such a claim. Metabolism. Based on the discussion of immediately available literature on the drug, the drug can have effects on the gastrointestinal and urinary systems of the body. The datum that the drug can produce stains on the urine and on contact lenses indicates that there are other body metabolisms involved in the body’s absorption of phenazopyridine. However, as pointed out earlier, even the NIH had declared in September 2010 that many pharmokinetic properties of phenazopyridine have not yet been determined. III. Phenazopyridine Pharmacodynamics Pharmacodynamics pertains to drug action and effects within the body (Roach 7). Roach defines the toxicity of a drug for its potential or actual capability to produce harmful or adverse effects to humans (3, 10). In contrast, the therapeutic effect of the drug refers to its desirable effects (Roach 7). Interaction at the Tissue or Effector Organ. Roach described phenazopyridine as “a dye that exerts a topical analgesic effect on the lining of the urinary tract” (460). The NIH said that phenazopyridine “exerts a topical analgesic effect on the mucosa of the urinary tract” and “the action helps to relieve pain, burning, urgency and frequency.” Toxic Effects. Making their report in 2009, the 2005 study of Jane Hui, Marie-Andree Harvey, and Shawna Johnston found out that there was no unexplained reaction or unexplained reaction or allergic that can be attributed to the administration of phenazopyridine (847). Thus, the 2005 study of Hui (reported only in 2009) possibly indicates that phenozapyridine, provided t that it is only taken for two days, may have no long-term fundamental or life-threatening toxic effect and that the risk of using phenazopyridne is principally located in the possibility that phenozapyridine may serve to mask an infection in the urinary tract given the analgesic effect of the drug. Nevertheless, it must be pointed out that the study of Hui, Harvey and Johnston, however, used only 32 cases from a sample of 124 women studied. The use of phenazopyridine on the sample was merely “confirmed in the medical chart, by the presence of either written orders, dictated notes stating that phenazopyridine was used , or nurses’ notes documenting administration” (Hui, Harvey and Johnston 847). Further, it must be emphasized that the NIH pointed out that phenazopyridine is contraindicated for “patients with renal insufficiency, severe liver disease, severe hepatitis or pyelonephritis of pregnancy” (“Phenazopyridine HCL” 1). The NIH also advised that phenazopyridine should be used cautiously in the presence of gastrointestinal disturbance (“Phenazopyridine HCL” 1). Based on a NIH assessment, there is a possibility that phenozapyridine HCL is carcinogenic for humans. The NIH also reported that overdose of the drug can impair renal functions especially among the elderly (“Phenazopyridine HCL” 3). Methemoglobinemia generally happens with an overdose of the drug and, in addition, hemolytic anemia may take place (“Phenazopyridine HCL” 3). The same information is also confirmed by the study of Christensen et al. (112). Data on over dosage, therefore, indicates toxic effects on the body’s circulatory system and human blood characteristics. Therapeutic Effects. Phenazopyridine is “a urinary tract analgesic used to relieve the pain, burning, urgency, frequency, and irritation caused by infection, trauma, catheters, or surgical procedures of the urinary tract” (Roach 460). The drug is used for the “relief of pain associated with the irritation of the lower genitourinary tract” (Roach 458). In other words, phenazopyridine treats only the symptoms but not the cause of the disorder (Roach 461). Mechanism of Action for Toxicity or Therapy. The therapeutic benefits of phenazopyridine arise from a topical analgesic effect of the phenazopyridine on the mucosa of the urinary tract (“Phenazopyridine HCL” 1). This effect relieves the feeling of pain, burning, urgency and frequency of urination (“Phenazopyridine HCL” 1). Prolonging urination too long can be bad for those with kidney and other ailments. Meanwhile, many of what we know on phenazopyridine is based on the study of experimental animals, especially with regard to its possible carcinogenic effects (“Phenazopyridine HCL” 1). Phenzopyridine HCL “increased the incidences of hepatocellular adenomas and carcinomas in female mice and adenomas and adenocarcinomas of the colon and rectum in rats of both sexes” (“Phenazopyridine HCL” 1). Thus, the drug is “reasonably anticipated to be a human carcinogen” (“Phenazopyridine HCL” 1). Evidence for human carcinogenicity for humans, however, is inadequate because “in one limited epidemiological study, no significant excess of any cancer was observed among 2,214 patients who received phenazopyridine hydrochloride and were followed for a minimum of 3 years” (“Phenazopyridine HCL” 1). Although it did not clarify its bases, the NIH warned that prescription of phenazopyridine should be done cautiously among patients with G-6-PD deficiency because the said patients “are susceptible to oxidative hemolysis and may have greater potential to develop hemolytic anemia” (“Phenazopyridine HCL” 1). This datum indicates that more studies are needed on phenazopyridine and those in the medical profession must be warned on the risks of using or prescribing phenazopyridine. Side Effects or Secondary Effects. The side effects from using phenazopyridine as identified by the U.S. NIH include the turning of the urine into red-orange or brown, headaches, dizziness, upset stomach, yellowing of the skin or yes, fever, confusion, skin rash, decreases in the amount of the urine, and parts of the body swelling (“Phenazopyrdine” 7th paragraph). According to the NIH, phenazopyrine can interfere with laboratory tests (including urine tests for blood sugar or ketones) and stains clothes and contact lenses (“Phenazopyrdine” tenth paragraph). One source, also from the NIH, indicates that phenopyridine can stain even human feces (“Phenazopyrdine HCL” 1). Roach added to the list of side effects the possibility of rashes, pruritus, yellowish discoloration of the skin or sclera, and gastrointestinal difficulties (458, 460). Perhaps, it is also appropriate to add that one important side effect of phenazopyridine is that it can “mask pathological conditions and interfere with laboratory tests using colorimetric, spectrophotometric or fluorometric analysis methods” (“Phenazopyridine HCL” 1). IV. Conclusion Based on the therapeutic benefits of the phenazopyridine or phenazopyridine HCL, it is wise not to prescribe the drug when there no great need for comfort given the feeling of pain, burning pain, urgency, and frequency of urination. If prescribing the drug is desired in view of a need to provide comfort and relief for patients, it appears wise not to have the patient use the drug for more than two days provided the patient is not pregnant and does not have kidney, liver, renal, and gastrointestinal problems. According to the NIH, the benefits of using the drug for more than two days do not outweigh the benefits of using only an antimicrobial or executing a surgery. If pregnancy and the conditions identified are present, other strategies or drugs should be considered to address the pain, burning pain, urgency and frequency associated with the patient urination. One must also heed the advice of the NIH for those in the medical profession to ask their patient to take phenazopyridine after eating or snack “to reduce stomach upset” (“Phenazopyridine HCL” 1). Works Cited Christensen, C.M., H.C. Farrar, and CL Kearns. “Protracted Methemoglobinemia after Phenazopyridine Overdose in an Infant.” Journal of Clinical Pharmacology 36.2 (1996): 112-116. Duffield, Patricia. “Managing Urinary Tract Infections Part 1: Diagnosing and Treating Adults.” American Journal of Nursing 96.9 (September 1996): 16b-16c. Hiren, Mehta, Patel Paresh, and Galani Varsha. “Factors Affecting Pharmakinetic Disposition of Drugs.” International Research Journal of Pharmacy 2.5 (2011): 106-114. Hui, Jane, Marie-Andree Harvey, and Shawna Johnston. “Confirmation of Uteric Patency during Cystoscopy Using Phenazopyridine HCL: A Low-Cost Approach.” JOGC September (2009): 845-849. National Institutes of Health (NIH). “Phenazopyridine.” U.S. National Institute of Health: U.S. National Library of Medicine, 1 October 2010. Web. 10 November 2011. . National Institutes of Health (NIH). “Phenazopyridine HCL.” U.S. National Institute of Health: U.S. National Library of Medicine, September 2010. Web. 10 November 2011.< http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=48244> Roach, Sally. Introductory Clinical Pharmacology. 7th ed. Philadelphia: William & Wilkins, 2006. Read More