Ofloxacin and lomefloxacin are second‑generation fluoroquinolone antibiotics commonly covered in B. Pharm pharmacology modules. This introduction reviews mechanism of action (DNA gyrase/topoisomerase IV inhibition), pharmacokinetics, antimicrobial spectrum, clinical indications, adverse effects (tendon toxicity, CNS effects, phototoxicity), drug interactions (divalent cation chelation, warfarin potentiation), dosing considerations, and resistance mechanisms relevant to exam preparation. Emphasis is on differences between ofloxacin and lomefloxacin—absorption, metabolic pathways, safety profiles, and therapeutic uses—so students can apply knowledge clinically and in exams. Clear understanding of these concepts improves rational drug use and safe dispensing. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which is the primary mechanism of antibacterial action of ofloxacin and lomefloxacin?
- Inhibition of cell wall synthesis
- Inhibition of DNA gyrase and topoisomerase IV
- Inhibition of protein synthesis at 30S ribosomal subunit
- Disruption of bacterial folate synthesis
Correct Answer: Inhibition of DNA gyrase and topoisomerase IV
Q2. Which pharmacodynamic characteristic best describes fluoroquinolones like ofloxacin and lomefloxacin?
- Time-dependent killing
- Concentration-dependent killing with significant post‑antibiotic effect
- Bacteriostatic action only
- Synergistic only when combined with beta‑lactams
Correct Answer: Concentration-dependent killing with significant post‑antibiotic effect
Q3. Compared to ofloxacin, lomefloxacin is particularly associated with which adverse effect?
- Higher incidence of tendon rupture
- Marked phototoxicity
- Severe nephrotoxicity
- Profound bone marrow suppression
Correct Answer: Marked phototoxicity
Q4. Which of the following is a common route of elimination for ofloxacin?
- Hepatic metabolism only
- Renal excretion of unchanged drug
- Biliary excretion as active metabolites
- Exhalation via lungs
Correct Answer: Renal excretion of unchanged drug
Q5. A major mechanism by which bacteria develop resistance to fluoroquinolones is:
- Production of beta‑lactamase enzymes
- Mutations in DNA gyrase (gyrA) and topoisomerase IV genes
- Alteration of peptidoglycan cross‑linking
- Increased uptake through porins
Correct Answer: Mutations in DNA gyrase (gyrA) and topoisomerase IV genes
Q6. Which clinical indication is ofloxacin commonly used for?
- Uncomplicated urinary tract infections and prostatitis
- Uncomplicated viral pharyngitis
- First‑line treatment for tuberculosis
- Topical antifungal infections
Correct Answer: Uncomplicated urinary tract infections and prostatitis
Q7. Which drug interaction is important to counsel patients about when prescribing ofloxacin or lomefloxacin?
- Increased absorption with antacids containing magnesium or aluminum
- Reduced absorption when co‑administered with divalent/trivalent cations (e.g., antacids, sucralfate)
- Complete inactivation by metoclopramide
- Enhanced clearance with grapefruit juice
Correct Answer: Reduced absorption when co‑administered with divalent/trivalent cations (e.g., antacids, sucralfate)
Q8. Which adverse effect requires caution when prescribing fluoroquinolones to elderly patients, especially those on corticosteroids?
- Auditory neuropathy
- Tendonitis and tendon rupture
- Hyperglycemia
- Severe constipation
Correct Answer: Tendonitis and tendon rupture
Q9. A known CNS adverse effect of ofloxacin and lomefloxacin is:
- Excessive sedation and coma
- Anxiety, insomnia, and risk of seizures
- Peripheral neuropathy with demyelination
- Acute encephalitis
Correct Answer: Anxiety, insomnia, and risk of seizures
Q10. Which statement about phototoxicity and lomefloxacin is correct?
- Lomefloxacin has a lower phototoxic potential than all other fluoroquinolones
- Lomefloxacin is associated with a relatively high risk of phototoxic reactions compared to some other fluoroquinolones
- Phototoxicity is not a concern with any fluoroquinolones
- Lomefloxacin prevents phototoxicity when taken with vitamin D
Correct Answer: Lomefloxacin is associated with a relatively high risk of phototoxic reactions compared to some other fluoroquinolones
Q11. Which laboratory parameter is most important to monitor in patients on prolonged ofloxacin therapy?
- Blood glucose only
- Renal function (serum creatinine, eGFR)
- Serum bilirubin weekly
- Serum amylase
Correct Answer: Renal function (serum creatinine, eGFR)
Q12. The tendency of fluoroquinolones to prolong the QT interval is a concern because it may lead to:
- Hypotension resistant to therapy
- Torsades de pointes and life‑threatening arrhythmias
- Peripheral arterial thrombosis
- Bradykinesia
Correct Answer: Torsades de pointes and life‑threatening arrhythmias
Q13. Which resistance determinant can be plasmid‑mediated and contribute to reduced susceptibility to fluoroquinolones?
- Beta‑lactamase TEM genes
- qnr genes encoding pentapeptide repeat proteins
- erm methylase genes
- mecA gene
Correct Answer: qnr genes encoding pentapeptide repeat proteins
Q14. Of the following, which patient population is generally advised to avoid fluoroquinolones like ofloxacin and lomefloxacin?
- Adults with uncomplicated cystitis
- Pregnant women and growing children due to potential cartilage toxicity
- Elderly with renal impairment
- Patients with mild seasonal allergies
Correct Answer: Pregnant women and growing children due to potential cartilage toxicity
Q15. Which metabolic or excretory characteristic differentiates lomefloxacin from some other fluoroquinolones?
- Extensive hepatic metabolism to inactive glucuronides only
- Significant renal excretion but also notable hepatic metabolism in some patients
- Excretion primarily via the lungs
- Complete metabolism to inactive amino acids
Correct Answer: Significant renal excretion but also notable hepatic metabolism in some patients
Q16. Which of the following best describes the antimicrobial spectrum of ofloxacin?
- Primarily active against obligate anaerobes only
- Broad spectrum against many Gram‑negative bacilli and some Gram‑positive cocci
- Antiviral and antifungal activity
- Exclusive activity against Mycobacterium tuberculosis
Correct Answer: Broad spectrum against many Gram‑negative bacilli and some Gram‑positive cocci
Q17. Which clinical consideration is important when switching a patient from intravenous to oral ofloxacin?
- Oral bioavailability of ofloxacin is poor and IV must be continued
- Oral ofloxacin has good bioavailability and is often suitable for step‑down therapy
- Oral ofloxacin causes severe GI ulcers and should be avoided
- Oral form cannot achieve therapeutic levels in urinary tract
Correct Answer: Oral ofloxacin has good bioavailability and is often suitable for step‑down therapy
Q18. Which adverse effect has been reported with fluoroquinolones and may persist after discontinuation?
- Transient hyperpigmentation only during therapy
- Peripheral neuropathy that can be persistent
- Immediate and complete recovery of tendon function always
- Reversible alopecia within 24 hours
Correct Answer: Peripheral neuropathy that can be persistent
Q19. Chelation with divalent cations reduces absorption of fluoroquinolones. Which advice is correct?
- Take fluoroquinolones simultaneously with calcium supplements for better absorption
- Separate administration of antacids, iron or calcium supplements by 2–4 hours from the fluoroquinolone dose
- Antacids have no effect on fluoroquinolone absorption
- Crush all tablets and mix with milk to avoid interaction
Correct Answer: Separate administration of antacids, iron or calcium supplements by 2–4 hours from the fluoroquinolone dose
Q20. Which laboratory test or monitoring is most relevant if a patient on fluoroquinolones develops muscle pain and weakness?
- Serum amylase
- Serum creatine kinase (CK) to evaluate for muscle injury or tendon damage
- Fasting lipid profile
- Serum bilirubin
Correct Answer: Serum creatine kinase (CK) to evaluate for muscle injury or tendon damage
Q21. Which structural feature is characteristic of fluoroquinolones as a class?
- Beta‑lactam ring fused to thiazolidine
- Fluorine atom at the C‑6 position on the quinolone nucleus
- Glycopeptide sugar moiety
- Polyene macrolide ring
Correct Answer: Fluorine atom at the C‑6 position on the quinolone nucleus
Q22. Which statement about dosing in renal impairment is true for ofloxacin?
- No dose adjustment is ever required regardless of renal function
- Dose adjustment or extended dosing interval may be required because of renal excretion
- Ofloxacin is contraindicated in mild renal impairment only
- Hepatic dose adjustment is the only concern
Correct Answer: Dose adjustment or extended dosing interval may be required because of renal excretion
Q23. Which interaction increases the risk of CNS adverse effects when combined with fluoroquinolones?
- Co‑administration with beta‑blockers
- Co‑administration with theophylline or NSAIDs may increase seizure risk
- Co‑administration with vitamin C reduces CNS toxicity
- Co‑administration with oral contraceptives prevents CNS effects
Correct Answer: Co‑administration with theophylline or NSAIDs may increase seizure risk
Q24. For ophthalmic infections, which fluoroquinolone formulation is commonly used and is of relevance to B.Pharm students?
- Intravenous lomefloxacin solution
- Ofloxacin ophthalmic drops
- Topical lomefloxacin oral suspension
- Ofloxacin transdermal patch
Correct Answer: Ofloxacin ophthalmic drops
Q25. Which factor contributes to selection of ofloxacin over other antibiotics for complicated urinary infections?
- Poor urinary excretion leading to low urinary concentrations
- Good penetration into prostatic tissue and high urinary concentrations
- Exclusive activity against anaerobic organisms
- Known lack of urinary side effects
Correct Answer: Good penetration into prostatic tissue and high urinary concentrations
Q26. Which pharmacokinetic parameter is most likely to influence once‑daily versus twice‑daily dosing decisions for fluoroquinolones?
- Volume of distribution only
- Plasma half‑life and AUC/MIC relationship
- Protein binding exclusively
- Color of the tablet coating
Correct Answer: Plasma half‑life and AUC/MIC relationship
Q27. Cross‑resistance among fluoroquinolones commonly occurs because:
- They share the same mechanism and target enzymes, so single mutations can confer cross‑resistance
- They are chemically unrelated
- Resistance to one improves susceptibility to others
- They always work synergistically
Correct Answer: They share the same mechanism and target enzymes, so single mutations can confer cross‑resistance
Q28. Which counselling point is appropriate regarding sun exposure for patients taking lomefloxacin?
- There is no need for sun protection
- Avoid excessive sunlight and use sunscreen due to increased phototoxic risk
- Intentional sunbathing enhances drug efficacy
- Only nighttime dosing avoids phototoxicity
Correct Answer: Avoid excessive sunlight and use sunscreen due to increased phototoxic risk
Q29. Which statement about the stereochemistry of ofloxacin is correct?
- Ofloxacin is a single L‑isomer only
- Ofloxacin is a racemic mixture of R‑ and S‑enantiomers; levofloxacin is the active S‑enantiomer
- Ofloxacin has no chiral centers
- Ofloxacin is an equal mixture of three stereoisomers
Correct Answer: Ofloxacin is a racemic mixture of R‑ and S‑enantiomers; levofloxacin is the active S‑enantiomer
Q30. When preparing exam answers on fluoroquinolones, which point is most important to include regarding safe use?
- Fluoroquinolones are completely free of serious adverse effects and need no monitoring
- Consider risk–benefit, monitor renal function, counsel on tendon and phototoxic risks, and avoid interacting agents
- They should be given with antacids to improve tolerance
- They are first‑line for all pediatric infections
Correct Answer: Consider risk–benefit, monitor renal function, counsel on tendon and phototoxic risks, and avoid interacting agents
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.
Mail- Sachin@pharmacyfreak.com