Zithrolex 500

Zithrolex 500

Zithrolex Suspension

Zithrolex Suspension

Commercial Name


Generic Name

Azithromycin USP


Zithrolex® 250 mg Capsule: Each Capsule contains Azithromycin Dihydrate USP equivalent to 250 mg Azithromycin USP.
Zithrolex®¬ 500 mg Capsule: Each Capsule contains Azithromycin Dihydrate USP equivalent to 500 mg Azithromycin USP.
Zithrolex®¬ Dry Powder for Suspension: When reconstituted, each 5ml suspension contains Azithromycin USP 200 mg as Azithromycin Dihydrate USP.


Zithrolex®¬ (Azithromycin) is and azalide antibiotic, subclass of the macrolide class of antibiotics. Zithrolex® (Azithromycin) acts by binding to the 50S ribosomal subunit of susceptible organisms and thus interferes with microbial protein synthesis. Zithrolex® demonstrated activity in vitro, against a wide range of Gram positive and Gram-negative bacteria including: Staphylococcus aureus, Streptococcus pneumonia, Streptococcus pyogenes (Group A) and other Streptococcus species; Haemophilus influenza and parainfluenzae; Moraxella catarrhalis; anaerobes including bacteroides fragilis, Escherichia coli, Bordetella pertussis, Bordetella parapertussis, Borrelia burgdorferi, Haemophilus ducreyi, Neisseria gonorrhoeae and chlamydia trachomatis. Zithrolex® also demonstrates activity in vitro against Legionella pneumophila, Mycoplasma pneumonia and hominis; Campylobacter spp. Toxoplasma gondii and Treponema pallidum.


Azithromycin is indicated for infections caused by susceptible organisms; in lower respiratory tract infections including bronchitis and pneumonia, skin and soft tissue infections, otitis media and in upper respiratory tract infections including sinusitis, pharyngitis and tonsillitis, in sexually transmitted diseases in men and women, Azithromycin is indicated in the treatment of uncomplicated genital infections due to Chlamydia trachomatis. It is also effective against certain sexually transmitted infectious diseases, such as nongonococcal urethritis and cervicitis, due to Chlamydi trachomatis.

Dosage & Administration

Azithromycin should be given as a single daily dose. Azithromycin capsule & suspension should be taken at least one hour before or two hours after meals since it may bind to food and not be absorbed from the intestine. Azithromycin 500 mg tablet can be taken with food.
Adults For lower respiratory tract infections including bronchitis and pneumonia, upper respiratory tract infections including sinusitis and pharyngitis/ tonsillitis, otitis media and skin and soft tissue infections, the total dose of Zithrolex® is 1.5g, which should be given as 500mg daily for 3 days or alternatively, initially, 500 mg as a single dose, followed by a 250 mg single dose daily for next 4 days.
For the treatment of sexually transmitted diseases caused by Chlamydia trachomatis, the dose is 1 g given as a single dose. Alternatively 500 mg once daily on day 1, followed by 250 mg once daily next 2 days may also be given.
In elderly: The same dose range as in younger patients may be used in the elderly.
In children: The dose of Zithrolex® in children over 6 months of age is 10 mg/kg body weight once daily for 3 days, Alternatively 10 mg/kg on day 1, followed by 5mg/kg for next 4 days is also recommended.
Under consideration body weight and age Zithrolex® can be recommended in following dosage.
Body Weight (Age) Dose Frequency of dose
15-25 kg (3-7 years) 200 mg Once daily for 3 days
26-35 kg (8-11 years) 300 mg Once daily for 3 days
36-45 kg (12-14 years) 400 mg Once daily for 3 days
For body weights over 45 kg, normal adult dosage is recommended.


Azithromycin is contraindicated in patients with known hypersensitivity to Azithromycin or any of the macrolide antibiotics. Because of the theoretical possibility of ergotism, Azithromycin and ergot derivatives should not be co-administered. As liver is the principal route of excretion of Azithromycin it should not be used in patients with hepatic disease.


Avoid concomitant administration with Terfenadine or Astimizole. Precaution should be taken in patients with more severe renal impairment.

Pregnancy and Lactation

Recent clinical studies have recommended that Azithromycin should be considered for the initial treatment of Chlamydial cervicitis in pregnancy. In other infections, Azithromycin should be used only when clearly needed. It is not known whether Azithromycin is excreted in breast milk. Exercise caution when administering to nursing women.

Side Effect

Zithrolex®¬ (Azithromycin) is well tolerated with a low incidence of side-effects. The side effects include nausea, vomiting, dizziness and skin rashes and are reversible upon discontinuation of therapy.

Drug Interaction

Antacids: Peak serum levels but not the total extent of absorption are reduced by aluminium and magnesium containing antacids in the stomach. Azithromycin should therefore be taken at least 1 hour before or 2 hours after taking these antacids.
Ergot derivatives: Because of the theoretical possibility of the ergotism, concomitant
Digoxin & Cyclosporine: Macrolides have been known to increase the plasma concentration of Digoxin and cyclosporine and so caution should be exercised while co administration is necessary.
Anit histamines: A potentially life threatening interaction between Erythromycin and Terfenadine or Astemizole has been reported. Although such as interaction with Azithromycin is not established yet, it is wide to avoid concomitant use of Azithromycin and Terfenadine or Astemizole.


There are no data on over dosage with Azithromycin. Typical symptoms of over dosage with macrolide antibiotics include hearing loss, severe nausea, vomiting and diarrhea. Gastric lavage and supportive measure are indicated.


Zithrolex® (Azithromycin) capsules and dry powder for suspension should be stored at room temperature (below 300 C). any unused portion of reconstituted Zithrolex® suspension should be discarded after 5 days.
Keep in a cool dry place and protect from light.
Keep out of the reach of children.

Pack Size

Zithrolex® 250 Capsule: Box containing 2X3’s Capsule in Alu-Alu blister pack
Zithrolex® 500 Capsule: Box cantaining 2×3’s Capsule in Alu-Alu blister pack
Zithrolex® Suspension: Each sealed cap amber glass bottle contains dry powder for reconstituting 15 ml Suspension.

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