Reproductive System Disorders Q 31

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Dr. Grey prescribes norfloxacin (Noroxin), 400 mg P.O. twice daily, for a client with a urinary tract infection (UTI). The client asks the nurse how long to continue taking the drug. For an uncomplicated UTI, the usual duration of norfloxacin therapy is:

  

    A. 3 to 5 days.

    B. 7 to 10 days.

    C. 12 to 14 days.

    D. 10 to 21 days.

    

    

Correct Answer: B. 7 to 10 days.

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For an uncomplicated UTI, norfloxacin therapy usually lasts 7 to 10 days. Oral quinolones are rapidly absorbed in the gastrointestinal tract and possess a high oral bioavailability, allowing the oral and IV routes of administration to be used interchangeably for certain quinolones. Though quinolones are widely distributed throughout the body, the degree of penetration into tissues and bodily fluids depends on the individual quinolone.

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Option A: Taking the drug for less than 7 days wouldn’t eradicate such an infection. Most quinolones are predominantly eliminated unchanged by the kidney via glomerular filtration and some degree of tubular secretion. They are typically eliminated through the hepatic and trans-intestinal routes to a lesser extent, though the degree to which they undergo elimination through these routes depends on the individual quinolones.

Option C: Taking it for more than 10 days isn’t necessary. Concurrent consumption of food (including dairy products) with oral quinolones has minimal effect on its absorption and activity. However, oral absorption of quinolones substantially decreases when taken together with other medications containing metallic cations due to the chelation that occurs between quinolone functional groups and the cations leading to the formation of an insoluble compound.

Option D: Only a client with a complicated UTI must take norfloxacin for 10 to 21 days. Multiple studies have observed an increase in the elimination half-life of various quinolones with decreasing creatinine clearance. As such, patients with renal impairment should have their quinolone dosage adjusted according to their respective renal function.

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