LEC 7 UTI ANTIBIOTICS_removed

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  • UTIs are prevalent in women of child-bearing age and in the elderly population.

  • E. coli is the most common pathogen, causing about 80% of uncomplicated upper and lower UTIs.

  • Staphylococcus saprophyticus is the second most common bacterial pathogen causing UTIs.

  • UTIs may be treated with urinary tract antiseptics such as methenamine, nitrofurantoin, and nalidixic acid.

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  • Urinary tract antiseptics do not achieve antibacterial levels in the circulation.

  • They are concentrated in the urine, allowing for effective eradication of microorganisms at that site.

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  • Methenamine decomposes at an acidic pH of 5.5 or less in the urine, producing formaldehyde.

  • Formaldehyde acts locally and is toxic to most bacteria.

  • Bacteria do not develop resistance to formaldehyde.

  • Methenamine is often formulated with a weak acid to keep the urine acidic.

  • The urinary pH should be maintained below 6.

  • Antacids should be avoided.

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  • Methenamine is primarily used for chronic suppressive therapy to reduce the frequency of UTIs.

  • It is not generally recommended for routine use in patients with chronic urinary catheterization.

  • Methenamine should not be used to treat upper UTIs.

  • Urea-splitting bacteria like Proteus species are usually resistant to methenamine.

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  • Methenamine can irritate the gastrointestinal (GI) tract, leading to symptoms like nausea, vomiting, abdominal pain, and diarrhea.

  • Formaldehyde, a byproduct of methenamine's metabolism, can be irritating to the stomach lining.

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  • Some individuals may be allergic to methenamine or its components, leading to allergic reactions such as rash, itching, swelling, or difficulty breathing.

  • Allergic reactions can occur with any medication and are usually due to an individual's immune system overreacting to the drug.

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  • Methenamine can lead to kidney problems, including crystalluria and renal insufficiency.

  • Methenamine can form crystals in the urine, potentially obstructing the urinary tract and damaging the kidneys.

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  • Methenamine can lead to bladder irritation and discomfort.

  • The formaldehyde produced in the urine can irritate the bladder lining, causing symptoms like urgency, frequency, and painful urination.

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  • Sulfonamides like cotrimoxazole should not be used concomitantly with methenamine.

  • The combination increases the risk of crystalluria and mutual antagonism.

  • Methenamine is contraindicated in patients with renal insufficiency due to potential renal damage from formaldehyde.

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  • Nitrofurantoin is a bactericidal antibiotic used for the treatment of uncomplicated lower urinary tract infections.

  • It is effective against most gram-positive and gram-negative organisms.

  • Nitrofurantoin is activated inside bacteria by reduction via the flavoprotein nitrofurantoin reductase to unstable