First of all, it is important to know that Zithromax or Azithromycin (known as azalide, which has nitrogen in the macrolide ring) is an antibiotic from the macrolide subclass (see also erythromycin)which is given to someone who is allergic to penicillin. It is used also for moderate infections(pneumonia,pharyngitis,strep throat) , Zithromax not being a first line antibiotic, but becoming one, when penicillin administation is impossible.
It is important the fact that due to the prolonged period of remaining in the human body,because of the stability of molecule, Zithromax can be taken just for 3 days, or even better, in a cure for one day. This aspect is valuable mainly in Pediatric field, where prolonged administration of a medicine, especially antibiotics, could become very difficult, if the sick child doesn't like to take drugs.
From pharmacokinetic point of view, due to the large amount of phagocytes, the Azithromycin goes directly to the infection place; the concentration of Azithromycin in tissues could reach a 50 times higher value, than in plasma.
The active ingredient in the prescription drug, ZITHROMAX is the antibiotic AZITHROMYCIN.
Azithromycin is a semi-synthetic macrolide antibiotic chemically related to erythromycin and clarithromycin(Biaxin). It is effective against a wide variety of bacteria such as Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Staphylococcus aureus, mycobacterium avium, and many others. Azithromycin, like all macrolide antibiotics, prevents bacteria from growing by interfering with their ability to make proteins. Due to the differences in the way proteins are made in bacteria and humans, the macrolide antibiotics do not interfere with production of proteins in humans. It is an unusual antibiotic in that it stays in the body for quite a while (has a long half-life), allowing for once a day dosing and for shorter treatment courses for most infections. The FDA approved azithromycin in November 1991.