Molecular Biology: DNA Inhibition Mechanisms

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What is the spectrum of activity of rifampicin?

Only Gram -ve bacteria

Only Gram +ve bacteria

All bacteria

Gram +ve bacteria and some Gram -ve bacteria (correct)

What is the route of administration of rifampicin?

IM only

Topical only

SC only

PO or IV (correct)

What is the mechanism of action of rifampicin?

Inhibition of RNA polymerase

Inhibition of nucleotide synthesis

Inhibition of DNA gyrase

Binding to the enzyme and inducing conformational change (correct)

What is the metabolism of rifampicin?

Liver only Signup and view all the answers

What is the side effect of metronidazole when consumed with alcohol?

Disulfiram-like effect Signup and view all the answers

What type of infection is caused by Clostridioides difficile?

Pseudomembranous colitis Signup and view all the answers

Which of the following is a clinical indication for metronidazole?

Infections caused by anaerobic bacteria Signup and view all the answers

What is the side effect of metronidazole that affects the liver?

Increased LFTs, cholestasis or mixed hepatitis Signup and view all the answers

What type of infection is caused by Trichomonas vaginalis?

Urogenital trichomoniasis Signup and view all the answers

What is the mechanism by which sulphonamides inhibit bacterial growth?

Bacteriostatic Signup and view all the answers

Why are sulphonamides not usually administered topically?

Due to risk of allergic reactions Signup and view all the answers

What is the mechanism of resistance to sulphonamides?

Production of an enzyme that is insensitive to the drug Signup and view all the answers

What is the exception to good oral absorption of sulphonamides?

Sulfasalazine Signup and view all the answers

What is the main use of cotrimoxazole?

Treatment of Pneumocystis jiroveci infections Signup and view all the answers

What is a common side effect of sulphonamides?

GI disturbances Signup and view all the answers

What is the consequence of methaemoglobinaemia caused by sulphonamides?

Cyanosis Signup and view all the answers

What is the skin manifestation of hypersensitivity reaction to sulphonamides?

Erythema multiforme Signup and view all the answers

What is the result of sulphomanides unbinding bilirubin from albumin?

Increased blood level of bilirubin Signup and view all the answers

What is the mechanism of action of trimethoprim?

Competing with folate for dihydrofolate reductase Signup and view all the answers

What is the spectrum of activity of trimethoprim?

Most bacterial pathogens, except enterococci and P.aeruginosa Signup and view all the answers

What is the effect of trimethoprim on bacterial growth?

Bacteriostatic Signup and view all the answers

What is the pharmacokinetic characteristic of trimethoprim?

Fully absorbed in the GIT Signup and view all the answers

What is the risk associated with sulphomanides in premature infants?

Risk of kernicterus Signup and view all the answers

What is the effect of trimethoprim on methotrexate and warfarin?

Increased activity Signup and view all the answers

What is the administration route of trimethoprim?

PO only Signup and view all the answers

What percentage of orally administered trimethoprim can be recovered in the urine within 24 hours?

60% Signup and view all the answers

What is the main use of trimethoprim?

Urinary tract infections Signup and view all the answers

What is the combination of sulfamethoxazole and trimethoprim used for?

Treating Pneumocystis jiroveci infections Signup and view all the answers

What is a common side effect of trimethoprim?

All of the above Signup and view all the answers

Why do hypersensitivity reactions occur with cotrimoxazole?

Due to the sulfamethoxazole component Signup and view all the answers

What is the advantage of using cotrimoxazole over trimethoprim?

Cotrimoxazole has slowed resistance Signup and view all the answers

What is the mechanism of action of sulphonamides?

Mimicking PABA to disrupt folate production Signup and view all the answers

What is the reason for giving folic acid supplements with trimethoprim?

To prevent folate deficiency Signup and view all the answers