Nucleic Acid Function & Synthesis Inhibitors
Function Inhibitors: Fluroquinolones, Nitrofurantoin and Methenamine
Synthesis Inhibitors: Sulphonamides and Trimethoprim
FLUROQUINOLONES
1st Generation: Nalidixic Acid, Pipemedic Acid
2nd Generation: Ofloxacin, Ciprofloxacin
3rd Generation: Levofloxacin, Gemifloxacin
4th Generation: Moxifloxacin, Trovafloxacin
Nalidixic Acid is the1st Synthetic Quinolone; Upon Fluorination forms Fluroquinolones
MOA: Inhibits 2 important enzymes 1) Topoisomerase (separates daughter DNA after replication) and
2) DNA Gyrase (coils circular DNA). DNA Gyrase has 2A and 2B subunits FQ binds to A subunit.
Topoisomerase targets Gram positive bacteria and DNA Gyrase targets Gram negative bacteria.
Spectrum: 1st Gen; Gram negative and some Gram Positive. 2nd Gen; Extended Gram negative. 3rd
Gen; Expanded Gram negative plus anaerobes. 4th Gen; Anaerobes plus Gram positive.
Uses: UTI, Anthrax, Prostatitis, Cervitis, Gonorrhoea, Pseudomonal Infections.
SE: GI disturbances, Nausea, Insomnia, Tendonitis and Tendon Rupture, Prolongs QT interval.
NOT GIVEN IN PREGNANCY OR WITH TRIVALENT CATIONS SUCH AS CHELATES, CALCIUM, ZINC, IRON,
MAGNESIUM
NITROFURANTOIN
Urinary antiseptic; Prophylaxis of UTI; Absorption ↑ with food.
MOA: Nitrofurantoin converted to Reactive intermediary with the help of Nitrofurantoin Reductase.
Intermediaries affect DNA, RNA and Protein Synthesis.
Uses: UTI, Hepatitis
METHENAMINE
Aromatic Acid used as urinary antiseptic. Administered as salt of Mandelic Acid or Hippuric Acid.
Hydrolysed to Formaldehyde and Ammonia. Formaldehyde acts as an antiseptic.
Used as a urinary antiseptic to prevent UTI
Mandelic Acid can crystallize in urine and irritate bladder. Sulphonamide given alongside to
prevent this as it condenses with Methenamine and prevents crystalluria.
Function Inhibitors: Fluroquinolones, Nitrofurantoin and Methenamine
Synthesis Inhibitors: Sulphonamides and Trimethoprim
FLUROQUINOLONES
1st Generation: Nalidixic Acid, Pipemedic Acid
2nd Generation: Ofloxacin, Ciprofloxacin
3rd Generation: Levofloxacin, Gemifloxacin
4th Generation: Moxifloxacin, Trovafloxacin
Nalidixic Acid is the1st Synthetic Quinolone; Upon Fluorination forms Fluroquinolones
MOA: Inhibits 2 important enzymes 1) Topoisomerase (separates daughter DNA after replication) and
2) DNA Gyrase (coils circular DNA). DNA Gyrase has 2A and 2B subunits FQ binds to A subunit.
Topoisomerase targets Gram positive bacteria and DNA Gyrase targets Gram negative bacteria.
Spectrum: 1st Gen; Gram negative and some Gram Positive. 2nd Gen; Extended Gram negative. 3rd
Gen; Expanded Gram negative plus anaerobes. 4th Gen; Anaerobes plus Gram positive.
Uses: UTI, Anthrax, Prostatitis, Cervitis, Gonorrhoea, Pseudomonal Infections.
SE: GI disturbances, Nausea, Insomnia, Tendonitis and Tendon Rupture, Prolongs QT interval.
NOT GIVEN IN PREGNANCY OR WITH TRIVALENT CATIONS SUCH AS CHELATES, CALCIUM, ZINC, IRON,
MAGNESIUM
NITROFURANTOIN
Urinary antiseptic; Prophylaxis of UTI; Absorption ↑ with food.
MOA: Nitrofurantoin converted to Reactive intermediary with the help of Nitrofurantoin Reductase.
Intermediaries affect DNA, RNA and Protein Synthesis.
Uses: UTI, Hepatitis
METHENAMINE
Aromatic Acid used as urinary antiseptic. Administered as salt of Mandelic Acid or Hippuric Acid.
Hydrolysed to Formaldehyde and Ammonia. Formaldehyde acts as an antiseptic.
Used as a urinary antiseptic to prevent UTI
Mandelic Acid can crystallize in urine and irritate bladder. Sulphonamide given alongside to
prevent this as it condenses with Methenamine and prevents crystalluria.
