Pharmacology Quiz: Fluoroquinolones and Aminoglycoside Antibiotics

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What is the mechanism of action of fluoroquinolones?

Inhibition of protein synthesis

Inhibition of cell wall synthesis

Inhibition of bacterial DNA synthesis by blocking topoisomerase II and IV (correct)

Activation of beta-lactamase

What type of organisms are fluoroquinolones effective against?

Gram-negative, atypical, gram-positive, and some mycobacteria (correct)

Only mycobacteria

Only gram-positive organisms

Only gram-negative organisms

Why are fluoroquinolones often prescribed?

For patients with a documented severe allergy to β-lactam antibiotics (correct)

For patients with a documented allergy to aminoglycosides

For patients with a severe allergy to macrolides

For patients with a severe allergy to tetracyclines

What is the effect of inhibition of topoisomerase IV?

Interference with separation of replicated chromosomal DNA Signup and view all the answers

What is the effect of inhibition of DNA gyrase?

Prevention of relaxation of positively supercoiled DNA Signup and view all the answers

What is the structure of fluoroquinolones?

Synthetic fluorinated analogs of nalidixic acid Signup and view all the answers

What is the reason why levofloxacin and moxifloxacin are referred to as “respiratory fluoroquinolones”?

They have excellent activity against S.pneumoniae Signup and view all the answers

What is the mechanism of resistance to fluoroquinolones?

Altered target and decreased accumulation Signup and view all the answers

What is the effect of divalent and trivalent cations on the oral absorption of fluoroquinolones?

It impairs the oral absorption Signup and view all the answers

What is the range of serum half-lives of fluoroquinolones?

3-10 hours Signup and view all the answers

What is the mechanism of elimination of most fluoroquinolones?

Renal mechanisms Signup and view all the answers

What is the bioavailability of fluoroquinolones after oral administration?

80-95% Signup and view all the answers

What is the typical time frame for absorption from an injection site in muscles to reach peak concentrations in blood?

30-90 minutes Signup and view all the answers

What is the normal half-life of aminoglycosides in serum?

2-3 hours Signup and view all the answers

What percentage of parenteral aminoglycosides are excreted unchanged in the urine?

More than 90% Signup and view all the answers

What is streptomycin mainly used for in mycobacterial infections?

As a second-line drug for tuberculosis Signup and view all the answers

What is the recommended dosage of streptomycin for children in the treatment of mycobacterial infections?

7.5-15 mg/kg/d Signup and view all the answers

What is gentamicin often used in combination with for the treatment of endocarditis caused by gram-positive bacteria?

A β-lactam antibiotic Signup and view all the answers

What is a common use of fluoroquinolones in urinary tract infections (UTIs)?

When the infection is caused by P.aeruginosa and resistant to cotrimoxazole Signup and view all the answers

What is a single dose of 500 mg of fluoroquinolone nearly 100% curative for?

Gonorrhea infections Signup and view all the answers

What type of bacterial infections are fluoroquinolones used in, especially in soft tissues and joints?

Resistant Staph. and gram negative bacteria Signup and view all the answers

What is ciprofloxacin used for in regards to anthrax?

Prophylaxis and treatment Signup and view all the answers

What is a common adverse effect of fluoroquinolones?

Nausea, vomiting, or diarrhea Signup and view all the answers

In what type of infections are fluoroquinolones occasionally used as an alternative?

Tuberculosis Signup and view all the answers

What is the concentration of gentamicin in creams, ointments, and solutions used for topical application?

0.1-0.3% Signup and view all the answers

What is the usual route of administration of gentamicin for treating meningitis caused by gram-negative bacteria?

Intrathecal Signup and view all the answers

What is the reason behind the nephrotoxicity of gentamicin?

All of the above Signup and view all the answers

What is the mechanism by which aminoglycosides reduce ACh release from the motor nerve endings?

Ca2+ antagonizing action Signup and view all the answers

What is a common reaction to topically applied neomycin?

Contact dermatitis Signup and view all the answers