Tag: Urinary Antiseptics

Urinary Antiseptics

URINARY ANTISEPTICS

Q. 1

A 25 year old female, presents to the clinic with dysuria, urinary frequency and urgency. After a laboratory workup a diagnosis of cystitis is made. Which is the first line drug for the treatment for this patient?

 A

Cephalexin

 B

Norfloxacin

 C

Amoxicillin

 D

Nitrofurantoin

Q. 1

A 25 year old female, presents to the clinic with dysuria, urinary frequency and urgency. After a laboratory workup a diagnosis of cystitis is made. Which is the first line drug for the treatment for this patient?

 A

Cephalexin

 B

Norfloxacin

 C

Amoxicillin

 D

Nitrofurantoin

Ans. D

Explanation:

First line agents used in the treatment of uncomplicated cystitis are Trimethoprim Sulfamethoxazole and Nitrofurantoin.

Nitrofurantoin is highly effective against E coli and most non E coli isolates. Second line agents used in its treatment are flouroquinolones and beta lactam antibiotics. Commonly used flouroquinolones in the treatment of UTI are ofloxacin, ciprofloxacin and levofloxacin.

Drugs used in the treatment of UTI in pregnancy are: nitrofurantoin, ampicillin and cephalosporins. Ampicillin and cephalosporins are the drugs of choice for the treatment of asymptomatic or symptomatic UTI in pregnant patients.

In pregnant patients with overt pyelonephritis parenteral beta lactam therapy with or without aminoglycosides is the standard of care. Ref: Harrison’s Principles of Internal Medicine, 18th edn, chapter 288


Q. 2

Drugs not causing hemolysis –

 A

Choloroquine

 B

Primaquine

 C

Nalidixic acid

 D

Nitrofurantoin

Q. 2

Drugs not causing hemolysis –

 A

Choloroquine

 B

Primaquine

 C

Nalidixic acid

 D

Nitrofurantoin

Ans. A

Explanation:

Ans. is ‘a’ i.e., Choloroquine


Q. 3

Drug not causing hemolysis in G6PD deficiency‑

 A

Primaquinc

 B

Chloroquine

 C

Nalidixic acid

 D

Nitrofurantoin

Q. 3

Drug not causing hemolysis in G6PD deficiency‑

 A

Primaquinc

 B

Chloroquine

 C

Nalidixic acid

 D

Nitrofurantoin

Ans. B

Explanation:

Ans. is ‘b’ i.e., Chloroquine 

  • Among the given options, chloroquine is the best answer (though it can also cause hemolysis, but very rarely).

Quiz In Between



Urinary Antiseptics

URINARY ANTISEPTICS


URINARY ANTISEPTICS

  • Oral drugs rapidly excreted via urine.
  • Suppresses bacterial growth in urinary tract.
  • More effective in acidic urine, – Due to low pH being an independent bacterial growth inhibitor.

Important urinary antiseptics:

  • Nitrofurantoin, methenamine mandelate & nalidixic acid.

Individual drug description:

1. Nitrofurantoin:

  • Active against most urinary pathogens, except Pseudomonas & Proteus.
  • Develops slow resistance.
  • Used infrequently.
  • MOA: 
    • Allows bacterial enzymes to act itself –> results in reduction of nitrofurantoin –> DNA damage.
  • Adverse effects: 
    • Diarrhea, phototoxicity, neurotoxicity, peripheral neuropathy & hemolysis in G-6-PD deficient patients.

2. Methenamine Mandelate:

  • Mandelate salt is used – Itself a urine acidifying agent.
  • Ineffective against Proteus – Due to NH release –> alkalinizing urine.
  • MOA:
    • Methenamine release formaldehyde at low pH (below 5.5).
    • Formaldehyde contributes to its antibacterial activity.
  • Contraindication:
    • Combination with sulfonamides.
    • Due to insoluble complex formation between formaldehyde & sulfonamides.

3. Nalidixic acid:

  • A quinolone drug.
  • MOA:  
    • Acts by inhibiting DNA gyrase.
    • Ineffective against pseudomonas & proteus.
    • Resistance emerges rapidly.
  • Adverse effect:
    • Neurotoxicity (major).

NOTE:

  • Phenazopyridine:
  • Has analgesic property & useful for alleviating symptoms of dysuria, frequency, burning & urgency.
  • Not a urinary antiseptic.

Exam Important

  • Urinary antiseptics suppresses bacterial growth in urinary tract.
  • Urinary antiseptics are particularly more effective in acidic urine, because of their low pH being an independent bacterial growth inhibitor.
  • Important urinary antiseptics include Nitrofurantoin, methenamine mandelate & nalidixic acid.
  • Nitrofurantoin is active against most urinary pathogens, except Pseudomonas & Proteus.
  • Infrequently used urinary antiseptic is Nitrofurantoin.
  • Adverse effects of nitrofurantoin include diarrhea, phototoxicity, neurotoxicity & hemolysis in G-6-PD deficient patients.
  • Mandelate salt is used itself a urine acidifying agent.
  • Methenamine Mandelate is ineffective against Proteus, due to NH release which alkalinizes urine.
  • Methenamine release formaldehyde at low pH (below 5.5), which contributes to its antibacterial activity.
  • Methenamine Mandelate is contraindicated in combination with sulfonamides, due to its insoluble complex formation between formaldehyde & sulfonamides.
  • Nalidixic acid is a quinolone drug.
  • Nalidixic acid acts by inhibiting DNA gyrase & are ineffective against pseudomonas & proteus.
  • Neurotoxicity is the major adverse effect of nalidixic acid.
  • Phenazopyridine has analgesic property & useful for alleviating symptoms of dysuria, frequency, burning & urgency, but is not a urinary antiseptic drug.
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