Question

Compare and contrast the mechanism of action of sulfonamides and fluoroquinolones and their therapeutics applications ?

Answer 1

Sulfonamides and Fluoroquinolones:

Both Sulfonamides and Fluoroquinolones are antibiotics that are used to treat different type of bacterial infections.  

Sulfonamides are a group of antibiotics , that are bacteriostatic in nature. They inhibit the growth of bacteria and are considered as the broad spectrum antibiotics . They are also called as Sulfa drugs.

Examples are Sulfamethizole, Sulfadiazine, Sulfametaxazole

Mechanism of Action: Sulfonamides interfers the Folate synthesis   in the bacteria by inhibiting the enzyme DHPS ( Dihydropteroate synthase) and there by inhibiting the growth of bacteria.

Fluoroquinolones are also considered as the broad spectrum antibiotics and are having the nature of bacteriostatic as well as bactericidal properties.  

Examples are: Ciprofloxacin, levofloxacin, norfloxacin .

Mechanism of Action: They bind to the enzyme- DNA complex and inhbit the supercoiling activity of DNA gyrase enzyme, thus inhibiting the DNA synthesis and replication in bacteria and kills susceptible bacterias.

Therapeutic applications : Sulfonamides are mainly used to treat:

* Urinary tract infections

* Ear infections

* Diarrhoea

* Pneumonia , bronchitis

* Eye infection

Contraindications: Sulfonamides are contraindicated in case of Group A Streptococcal pharyngitis, allergy to sulfonamides, porphyria and pregnancy.

Whereas Fluoroquinolones are mainly used for the indications of :

* Respiratory tract infections

* Urinary tract infections

* Pyelonephritis

* Prostatitis and epididymitis

* Profylactic antibiotic treatment in preoperative patients for trans urethral suegry

* Gastrointestinal infections.

Contraindications of Fluoroquinolones are Epilepsy, CNS inflammation and stroke.