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Name the first, second, third and fourth generations of Quinolones

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Quinolone Generations

Quinolones/fluoroquinolones are classified into four generations based on their spectrum of activity, reflecting structural modifications to the quinolone nucleus over time.
First generation - narrow-spectrum agents active mainly against aerobic gram-negative bacilli (mostly Enterobacteriaceae), with poor systemic absorption (used largely for UTIs)
  • Nalidixic acid, cinoxacin, oxolinic acid
Second generation - improved intracellular penetration and broader gram-negative coverage, plus activity against some atypicals
  • Ciprofloxacin, ofloxacin, norfloxacin, enoxacin, lomefloxacin
  • Coverage: Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Neisseria spp., Chlamydia spp., Legionella spp.
Third generation - retains second-generation gram-negative spectrum with added gram-positive coverage
  • Levofloxacin, sparfloxacin, gatifloxacin
  • Added coverage: Streptococcus spp. (including S. pneumoniae), methicillin-susceptible S. aureus, Stenotrophomonas maltophilia, Mycobacterium spp.
Fourth generation - enhanced gram-positive and anaerobic activity
  • Moxifloxacin, gemifloxacin, delafloxacin (trovafloxacin is an older fourth-gen agent largely withdrawn for hepatotoxicity)
  • Added coverage: Staphylococcus and Streptococcus spp., anaerobes (Bacteroides fragilis, Prevotella spp. - moxifloxacin/delafloxacin specifically); delafloxacin also covers MRSA and Enterococcus faecalis. Notably, most fourth-generation agents have minimal-to-no antipseudomonal activity (delafloxacin is an exception).
Sources:
  • Lippincott Illustrated Reviews: Pharmacology, 8th ed., p. 1020-1021
  • Tietz Textbook of Laboratory Medicine, 7th ed. - "Quinolones and Fluoroquinolones"
  • Dermatology, 2-Volume Set, 5th ed. - Indications section
A quick check of recent literature (systematic reviews/meta-analyses, last 2 years) didn't surface anything that changes this classic classification - it remains the standard teaching framework, though newer agents continue to be added to the fourth-generation/"next-generation" category in ongoing antibiotic development literature.

What about the drug, grifulaxacin?

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grifulaxacin drug

"Grifulaxacin" isn't a real drug - I can't find it in the medical library or any reliable web source. It doesn't correspond to any approved or investigational quinolone/fluoroquinolone I'm aware of.
It's possible you're thinking of one of these similarly-spelled real drugs instead:
  • Gemifloxacin - a real fourth-generation fluoroquinolone antibiotic (used for respiratory infections)
  • Griseofulvin - a real (unrelated) antifungal antibiotic, not a quinolone at all
If you meant one of these, let me know and I can go into detail. Otherwise, if you saw "grifulaxacin" somewhere specific (a textbook, question bank, or exam), it may be a typo, a fictional/test name, or a fabricated entry - I'd be cautious about treating it as a real pharmacological agent.
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