Friday, 10 August 2012

Anti Mycobacterial drugs



Anti Mycobacterial drugs



Q1. Pyridoxine deficiency is caused due to which of the following drugs?

  1. rifampin
  2. ethionamide
  3. isoniazid
  4. para-aminosalicyclic acid

Answer- 3
Isoniazid usage especially in alcoholics, diabetes, malnutrition and uremia can lead to pyridoxine deficiency and hence its symptoms such as neuropathy.

Q2.  Which of the following drugs inhibit DNA dependant RNA polymerase ?

  1. isoniazid
  2. pyrizinamide
  3. ethambutol
  4. rifampin

      Answer- 4

Q3.  Rahul AIDS and has acquired mycobacterium avium complex(MAC). Which of the following medication shouldn’t be dispensed to him along with reverse transcriptase inhibitor?

1.      isoniazid
2.      rifampin
3.      ethionamide
4.      ciprofloxacin

Answer-2
MAC is an opportunistic infection occurring mostly in immunocompromised patients such as HIV. Rifampin decreases activity of most reverse transcriptase inhibitors. It also causes contraceptive failure

Q4. Which of the following metabolite of isoniazid causes hepatotoxicity?

1.      n- acetyl isoniazid
2.      isonicotinic acid
3.      acetyl hydrazine
4.      diacetyl hydrazine

Answer-3





Q5. Discolouration of skin, sclera, tears etc can occur on prolonged use of which anti mycobacterial drug?

1.      rifampin
2.      clofazimine
3.      capreomycin
4.      dapsone

Answer- both 1and 2. Both the drugs are dyes

Q6. The action of which of the following anti mycobacterial drug is dependant on acidic pH?

1.      pyrizinamide
2.      isoniazid
3.      dapsone
4.      clofazimine

Answer- 1. Pyrazinamide diffuses into M. tuberculosis, where the enzyme pyrazinamidase converts pyrazinamide to the active form pyrazinoic acid. Under acidic conditions, the pyrazinoic acid that slowly leaks out converts to the protonated conjugate acid, which is thought to diffuse easily back into the bacilli and accumulate. The net effect is that more pyrazinoic acid accumulates inside the bacillus at acid pH than at neutral pH