Norfloxacin can cause musculoskeletal problems like tendon rupture and tendinitis, so its usage is warned.

Norfloxacin (at approved clinical doses) does not achieve adequate blood concentrations to treat systemic infections. However, it concentrates in the urine so it is effective against the infections cited by Elmer (UTI, prostatitis, STDs)

Norfloxacin concentrates almost exclusively in urine and can not reach enough seric levels to be distributes in other tisuues, so it can't be used to treat infections other than urinary

Hello

As we know norfloxacin is classified as second generation fluroquinolones. This category is effective mainly against gram negative bacteria and special types of gram positive like Chlamydia and Mycoplasma pneumonia. Referred to the most causative pathogens of skin and soft tissue infections (SSTIs) are gram positive ranged between Staphylococcus ("staph") bacteria (including MRSA) and  non-staph bacteria such as Group A Streptococcus (GAS). 

According to the National Library of Medicine, Norfloxacin is actually classified as a first generation fluoroquinolone.  Yes -  it has typically been used in UTI and prostatitis; however, it has been linked to rare instances of hepatocellular injury (MOA unknown- thought to be hypersensitivity).  Norfloxacin was first approved in the US in 1986 for the indications discussed above ...but it has also been used off label for SBP (spontaneous bacterial peritonitis) in patients with cirrohsis and ascites.  Norfloxacin has a similar side effect profile as other fluoroquinolones; however, some of the less common but more severe side effects include QT prolongation, seizures, hallucinations, tendon rupture angiodema and peripheral neuropathy.

Yes, it is first generation from fluroquinolones , but classified secondly as chemical classification of quinolones as a whole. First generation is nalidixic acid, which has narrow spectrum of activity against gram negative, so used for UTI. For this reason, the pharmacist made structure activity relationship (SAR) by adding flour atoms and side chains to improve the spectrum of activity and other pharmacokinetic problems.  

Thank you Doaa for explaining....

Norfloxacin and Nalidixic acid Plasma concetration (MIC) followed after the systemic absorption os not enough to use in systemic infections like soft tissue, bone ifections.But the these drugs are concentrated in two places , one is urinary tract and the other is GIT.Hence the Norflox is approved for the use in UTI and GI infections, Where as Nalidixic acid is approved as Urinary antispetic in UTI.

Hope you are clear about it.

Thank you

Norfloxacin is the It is the first of the fluoroquinolones, to be developed for clinical use.The fluoroquinolones are structurally related to nalidixic acid. The activity and spectrum are enhanced by the addition of 6-fluoro and 7-piperazino substituents. Quinolone antimicrobials appear to inhibit DNA gyrase, an enzyme specific and essential for all bacteria, as their primary mechanism of action.It was patented in 1978 and subsequently became the first fluoroquinolone to receive approval

from US Food and Drug Administration (FDA) in 1984.

Norfloxacin generally is less potent than ciprofloxacin, particularly against Ps. aeruginosa and Staph. aureus.