Kanamycin is an important aminoglycoside antibiotic whose chemistry and clinical use are essential topics for B. Pharm students. Its structure comprises an aminocyclitol core linked to amino sugars, producing concentration-dependent bactericidal activity by binding the 30S ribosomal subunit and disrupting protein synthesis. Key study areas include spectrum of activity (primarily aerobic Gram-negative bacilli), pharmacokinetics (poor oral absorption, renal elimination), dosing strategies, therapeutic drug monitoring, and adverse effects such as nephrotoxicity and ototoxicity. Also crucial are resistance mechanisms, formulation chemistry, stability, assay methods, and clinical applications including second-line use in tuberculosis. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary mechanism of action of kanamycin?
- Inhibition of cell wall synthesis by binding transpeptidases
- Binding the 30S ribosomal subunit and causing misreading of mRNA
- Inhibition of DNA gyrase
- Interference with folate synthesis
Correct Answer: Binding the 30S ribosomal subunit and causing misreading of mRNA
Q2. Chemically, kanamycin is classified as which of the following?
- A macrolide
- A tetracycline
- An aminoglycoside composed of an aminocyclitol linked to amino sugars
- A glycopeptide
Correct Answer: An aminoglycoside composed of an aminocyclitol linked to amino sugars
Q3. Which organism is the natural producer of kanamycin?
- Streptococcus pneumoniae
- Streptomyces kanamyceticus
- Bacillus subtilis
- Pseudomonas aeruginosa
Correct Answer: Streptomyces kanamyceticus
Q4. What is the main route of elimination for kanamycin?
- Hepatic metabolism and biliary excretion
- Renal excretion via glomerular filtration
- Exhalation through lungs
- Metabolism by intestinal flora
Correct Answer: Renal excretion via glomerular filtration
Q5. Which statement best describes kanamycin’s oral bioavailability for systemic infections?
- Excellent oral absorption, preferred oral therapy
- Poor oral absorption; administered parenterally for systemic infections
- Well absorbed with food but not on empty stomach
- Absorbed only when combined with proton pump inhibitors
Correct Answer: Poor oral absorption; administered parenterally for systemic infections
Q6. The two most clinically important toxicities associated with kanamycin are:
- Hepatotoxicity and cardiotoxicity
- Nephrotoxicity and ototoxicity
- Bone marrow suppression and pancreatitis
- Pulmonary fibrosis and photosensitivity
Correct Answer: Nephrotoxicity and ototoxicity
Q7. A common enzymatic mechanism of bacterial resistance to kanamycin involves:
- Beta-lactamase production
- Aminoglycoside-modifying enzymes (acetylation, adenylation, phosphorylation)
- Altered peptidoglycan synthesis
- Overproduction of folate
Correct Answer: Aminoglycoside-modifying enzymes (acetylation, adenylation, phosphorylation)
Q8. Kanamycin shows the greatest intrinsic activity against which group of bacteria?
- Anaerobic Gram-positive cocci
- Anaerobic Gram-negative bacilli
- Aerobic Gram-negative bacilli
- Obligate intracellular bacteria
Correct Answer: Aerobic Gram-negative bacilli
Q9. Which clinical use is historically associated with kanamycin?
- First-line oral therapy for community-acquired pneumonia
- Second-line injectable agent for multidrug-resistant tuberculosis and severe Gram-negative infections
- Long-term prophylaxis for urinary tract infections
- Topical antifungal therapy
Correct Answer: Second-line injectable agent for multidrug-resistant tuberculosis and severe Gram-negative infections
Q10. For therapeutic drug monitoring of kanamycin, which measurements are most useful?
- Only trough concentrations
- Only peak concentrations
- Both peak and trough plasma concentrations
- Urine culture counts only
Correct Answer: Both peak and trough plasma concentrations
Q11. Kanamycin’s activity against obligate anaerobes is generally:
- Highly effective
- Selective for Bacteroides species only
- Ineffective or poor due to oxygen-dependent uptake
- Equivalent to metronidazole
Correct Answer: Ineffective or poor due to oxygen-dependent uptake
Q12. Co-administration of kanamycin with loop diuretics increases the risk of which adverse effect?
- Hepatotoxicity
- Ototoxicity
- Hyperglycemia
- Thrombocytopenia
Correct Answer: Ototoxicity
Q13. Which statement about combining kanamycin with beta-lactam antibiotics is correct?
- They are always antagonistic and should never be combined
- They are synergistic clinically but may be physically incompatible if mixed in the same IV solution
- Beta-lactams prevent kanamycin nephrotoxicity
- They have identical mechanisms of action
Correct Answer: They are synergistic clinically but may be physically incompatible if mixed in the same IV solution
Q14. Regarding chemical stability, kanamycin solutions are most likely to degrade under which conditions?
- Neutral pH and refrigerated temperature
- High temperature and extreme pH (alkaline or acidic)
- Protected from light and stored cold
- When diluted in dextrose 5% only
Correct Answer: High temperature and extreme pH (alkaline or acidic)
Q15. Which analytical method is commonly used for quantitative determination of kanamycin in formulations and plasma?
- Colorimetric assay specific to macrolides
- HPLC (high-performance liquid chromatography)
- Gravimetric analysis
- Nitroblue tetrazolium reduction test
Correct Answer: HPLC (high-performance liquid chromatography)
Q16. The most common pharmaceutical salt form used for kanamycin preparations is:
- Kanamycin nitrate
- Kanamycin sulfate
- Kanamycin phosphate
- Kanamycin acetate
Correct Answer: Kanamycin sulfate
Q17. The pathophysiology of kanamycin-induced ototoxicity primarily involves damage to:
- Hepatocytes causing cholestasis
- Renal tubular epithelium exclusively
- Inner ear hair cells (cochlear and vestibular) often via reactive oxygen species
- Skeletal muscle causing weakness
Correct Answer: Inner ear hair cells (cochlear and vestibular) often via reactive oxygen species
Q18. Extended-interval (once-daily) dosing of kanamycin is used because:
- It reduces peak concentrations and eliminates toxicity
- Kanamycin exhibits time-dependent killing
- It exploits concentration-dependent killing and the post-antibiotic effect
- It causes less renal excretion
Correct Answer: It exploits concentration-dependent killing and the post-antibiotic effect
Q19. Topical ophthalmic kanamycin formulations are used clinically because they:
- Provide systemic exposure comparable to IV dosing
- Deliver high local concentrations with minimal systemic absorption
- Are better absorbed orally when taken with eye drops
- Are active against viral conjunctivitis
Correct Answer: Deliver high local concentrations with minimal systemic absorption
Q20. How is kanamycin characterized in terms of therapeutic index?
- Wide therapeutic index—very safe
- Narrow therapeutic index—requires careful monitoring
- Non-therapeutic agent used only in vitro
- Therapeutic index irrelevant due to topical use only
Correct Answer: Narrow therapeutic index—requires careful monitoring
Q21. Use of kanamycin during pregnancy is of concern primarily because it can:
- Cause maternal hypertension
- Induce fetal ototoxicity and potential hearing loss
- Enhance fetal bone growth
- Prevent gestational diabetes
Correct Answer: Induce fetal ototoxicity and potential hearing loss
Q22. Which laboratory test is most important to monitor regularly during kanamycin therapy?
- Liver enzymes (ALT/AST) only
- Serum creatinine and renal function tests
- Fasting blood glucose
- Thyroid-stimulating hormone (TSH)
Correct Answer: Serum creatinine and renal function tests
Q23. At the molecular level, kanamycin binds to which part of the ribosome?
- 23S rRNA of the 50S subunit
- 16S rRNA of the 30S subunit
- Peptidyl transferase center of 50S
- Exit tunnel of 50S
Correct Answer: 16S rRNA of the 30S subunit
Q24. High-level resistance to kanamycin in some bacteria is conferred by:
- Overexpression of porins to increase uptake
- 16S rRNA methyltransferases that methylate the drug binding site
- Increased peptidoglycan cross-linking
- Enhanced folate synthesis
Correct Answer: 16S rRNA methyltransferases that methylate the drug binding site
Q25. In a patient with reduced renal function, the elimination half-life of kanamycin is expected to be:
- Unchanged due to hepatic clearance
- Shorter because of increased metabolism
- Prolonged, necessitating dose adjustment
- Irrelevant to dosing decisions
Correct Answer: Prolonged, necessitating dose adjustment
Q26. Kanamycin should be used with caution or avoided in patients with myasthenia gravis because it can:
- Exacerbate muscle weakness via neuromuscular blockade
- Cause hypercoagulability
- Improve neuromuscular transmission
- Induce myelination of nerves
Correct Answer: Exacerbate muscle weakness via neuromuscular blockade
Q27. Which factor most accelerates chemical degradation of kanamycin in solution?
- Storage at refrigerated temperatures
- Presence of neutral buffering agents
- Exposure to elevated temperature and extreme pH
- Protection from light and oxygen
Correct Answer: Exposure to elevated temperature and extreme pH
Q28. Proper storage recommendations for kanamycin formulations generally include:
- Keep at high temperature and exposed to light
- Store per manufacturer label, protect from extreme heat and use reconstituted solutions within specified time
- Freeze all injectable vials
- Store only in direct sunlight to sterilize
Correct Answer: Store per manufacturer label, protect from extreme heat and use reconstituted solutions within specified time
Q29. Structurally, aminoglycosides like kanamycin are characterized by the presence of:
- Multiple amino and hydroxyl groups on sugar moieties attached to an aminocyclitol
- Single aromatic ring and a lactone
- Beta-lactam ring fused to a thiazolidine
- Macrocyclic lactone ring only
Correct Answer: Multiple amino and hydroxyl groups on sugar moieties attached to an aminocyclitol
Q30. Aminoglycoside-modifying enzymes that inactivate kanamycin act by which chemical modifications?
- Methylation of the 23S rRNA only
- Acetylation, adenylation (nucleotidylation), or phosphorylation of amino/hydroxyl groups on the drug
- Cleavage of the beta-lactam ring
- Oxidative deamination by hepatic enzymes
Correct Answer: Acetylation, adenylation (nucleotidylation), or phosphorylation of amino/hydroxyl groups on the drug
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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