Zithrox Lx

Uses

Azithromycin is used for infections caused by susceptible organisms in-

Upper respiratory tract infections including sinusitis, pharyngitis and tonsillitis

Lower respiratory tract infections including bronchitis, acute bacterial exacerbations of chronic obstructive pulmonary

disease (COPD)

Otitis media

Skin and soft tissue infections including cellulitis, pyoderma, erysipelas, wound infections

Diarrhea, Shigellosis

Sexually transmitted diseases, especially in the treatment of non-gonococcal urethritis and cervicitis due to Chlamydia trachomatis

Genital ulcer disease in men due to Haemophilus ducreyi (chancroid)

Mild or moderate typhoid due to multiple-antibacterial resistant organisms

Prophylaxis against a-hemolytic (viridans group) streptococcal bacterial endocarditis

Other infections including odontogenic infections, bartonella infections, toxoplasmosis, babesiosis

Levofloxacin Tablet is used for Acute maxillary sinusitis , Acute bacterial exacerbation of chronic bronchitis , Nosocomial pneumonia Community acquired pneumonia, Uncomplicated urinary tract infections Complicated urinary tract infections, Acute pyelonephritis, Uncomplicated & complicated skin and skin structure infections, Chronic bacterial prostatitis

Levofloxacin Injection is used to treat Acute maxillary sinusitis, acute bacterial exacerbation of chronic bronchitis, nosocomial pneumonia, community acquired pneumonia, uncomplicated urinary tract infections, complicated urinary tract infections, acute pyelonephritis, uncomplicated & complicated skin and skin structure infections including abscesses, cellulitis, furuncles, impetigo, pyoderma, wound infections, chronic bacterial prostatitis and typhoid fever.

Levofloxacin Injection has

• Proven clinical success in hospital infections
• Reaches high concentrations in lung, urine, skin and prostate
• Ensures excellent gram-positive and gram-negative bacterial coverage, Offers better option for switch therapy

Levofloxacin Eye drops is used for the treatment of corneal ulcer caused by susceptible strains of the following bacteria:

• Gram-positive Bacteria: Corynebacterium species, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Viridans group streptococci
• Gram-negative Bacteria: Pseudomonas aeruginosa, Serratia marcescens.

Zithrox Lx is also used to associated treatment for these conditions: Acute Bacterial Sinusitis (ABS), Acute Otitis Media, Acute bacterial exacerbation of COPD caused by Haemophilus Influenza Infections, Moraxella Catarrhalis Infection, Streptococcus Pneumoniae Infections, Bacterial Conjunctivitis, Bacterial Sinusitis, Cervicitis, Chancroid, Community Acquired Pneumonia (CAP), Genital Ulcer Disease (GUD), Pelvic Inflammatory Disease (PID), Pharyngitis, Streptococcal Pharyngitis, Streptococcal tonsillitis, Tonsillitis bacterial, Traveler's Diarrhea, Uncomplicated Skin and Skin Structure Infections, UrethritisAbscesses caused by susceptible bacteria, Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB) caused by susceptible bacteria, Acute Pyelonephritis caused by Infection Due to Escherichia Coli, Bacterial Conjunctivitis caused by susceptible bacteria, Cellulitis caused by susceptible bacteria, Community Acquired Pneumonia (CAP) caused by susceptible bacteria, Furuncle caused by susceptible bacteria, Impetigo caused by susceptible bacteria, Nosocomial Pneumonia caused by Pseudomonas Infections, Nosocomial Pneumonia caused by susceptible bacteria, Plague caused by Yersinia pestis, Pyoderma caused by susceptible bacteria, Wound Infections caused by susceptible bacteria, Acute bacterial sinusitis caused by susceptible bacteria, Chronic Bacterial prostatitis caused by susceptible bacteria, Chronic Pseudomonas Infections, Complicated Urinary Tract Infection caused by susceptible bacteria, Complicated skin and skin-structure infections caused by susceptible bacteria, Inhaled anthrax caused by Bacillus anthracis, Uncomplicated Urinary Tract Infection caused by susceptible bacteria, Uncomplicated skin and skin-structure infections caused by susceptible bacteria

How Zithrox Lx works

In order to replicate, bacteria require a specific process of protein synthesis, enabled by ribosomal proteins . Azithromycin binds to the 23S rRNA of the bacterial 50S ribosomal subunit. It stops bacterial protein synthesis by inhibiting the transpeptidation/translocation step of protein synthesis and by inhibiting the assembly of the 50S ribosomal subunit , . This results in the control of various bacterial infections , . The strong affinity of macrolides, including azithromycin, for bacterial ribosomes, is consistent with their broad‐spectrum antibacterial activities .

Azithromycin is highly stable at a low pH, giving it a longer serum half-life and increasing its concentrations in tissues compared to erythromycin .

Levofloxacin, like other fluoroquinolone antibiotics, exerts its antimicrobial activity via the inhibition of two key bacterial enzymes: DNA gyrase and topoisomerase IV. Both targets are type II topoisomerases, but have unique functions within the bacterial cell. DNA gyrase is an enzyme found only in bacteria that introduces negative supercoils into DNA during replication - this helps to relieve torsional strain caused by the introduction of positive supercoils during replication, and these negative supercoils are essential for chromosome condensation and the promotion of transcription initiation. It is comprised of four subunits (two A subunits and two B subunits) of which the A subunits appear to be the target of fluoroquinolone antibiotics. Bacterial topoisomerase IV, in addition to contributing to the relaxation of positive supercoils, is essential at the terminal stages of DNA replication and functions to “unlink” newly replicated chromosomes to allow for the completion of cell division.

Inhibition of these enzymes by levofloxacin likely occurs via complexation with the topoisomerase enzymes. The end result is a blockade of DNA replication, thus inhibiting cell division and resulting in cell death.

Dosage

Zithrox Lx dosage

Azithromycin tablet can be taken with or without food. Azithromycin suspension should be taken at least 1 hour before or 2 hours after meal.

Oral:

Adult:

For respiratory tract infections, otitis media and skin & soft tissue infections: 500 mg once daily for 3 days or an alternative to this as 500 mg once on day 1, followed by 250 mg once daily for next 4 days. For sexually transmitted diseases like genital ulcer, non-gonococcal urethritis and cervicitis due to Chlamydia trachomatis : a single 1 gm (1000 mg) dose. For the treatment of urethritis and cervicitis due to Neisseria gonorrhoeae : a single 2 gm (2000 mg) dose. In typhoid, 500 mg once daily for 7 days. In Cholera, a single 1 gm (1000 mg) dose. In Shigellosis, 500 mg once on day 1, followed by 250 mg once daily for next 4 days.

Acute sinusitis: 500 mg once daily for 10-14 days or 750 mg once daily for 5 days

Exacerbation of chronic bronchitis: 500 mg once daily for 7 days

Community acquired pneumonia: 500 mg once daily for 7-14 days or750 mg once daily for 5 days

Nosocomial pneumonia: 750 mg once daily for 7-14 days

Uncomplicated urinary tract infections: 250 mg once daily for 3 days

Complicated urinary tract infections and acute pyelonephritis: 250 mg once daily for 10 days

Complicated urinary tract infections and acute pyelonephritis: 750 mg once daily for 5 days

Uncomplicated skin and skin structure infections: 500 mg once daily for 7-10 daysComplicated skin and skin structure infections: 750 mg once daily for 7-14 days

Chronic bacterial prostatitis: 500 mg once daily for 28 days

Levofloxacin solution for infusion is administered by slow intravenous infusion once or twice daily. The dosage depends on the type and severity of the infection and the sensitivity of the causative pathogen. The duration of treatment varies according to the severity of the disease.Adult:

• Community-acquired pneumonia: 500 mg once or twice daily,
• Complicated urinary tract infections (including pyelonephritis): 250 mg once daily,
• Chronic bacterial prostatitis: 500 mg once daily,
• Skin and soft tissue infections: 500 mg twice daily
• Enteric fever: 500 mg once daily.

Children:

Levofloxacin can be used in children aged as low as 6 months. The usual dose for children in community acquired pneumonia is:

• Children aged 6 months to less than 5 years: 10 mg/kg b.i.d. (up to 500 mg per day) for 10 days,
• Children aged 5 years to 16 years: 10 mg/kg q.d. (up to 500 mg per day) for 10 days.

The usual dose for children in recurrent or persistent Acute Otitis Media is:

• Children aged 6 months to less than 5 years: 10 mg/kg per day (maximum dose: 500 mg/day) given twice daily for 10 days.

Paediatric Use: Levofloxacin is not recommended for children less than 6 (six) months of age.

Levofloxacin ophthalmic solution:

• Days 1 through 3: Instill one to two drops in the affected eye(s) every 30 minutes to 2 hours while awake and approximately 4 and 6 hours after retiring.
• Day 4 through treatment completion: Instill one to two drops in the affected eye(s) every 1 to 4 hours while awake.

0.5%ophthalmic solution:

• Days 1 and 2: Instill one to two drops in the affected eye(s) every 2 hours while awake, up to 8 times per day.
• Days 3 through 7: Instill one to two drops in the affected eye(s) every 4 hours while awake, up to 4 times per day.

Azithromycin can be taken with or without food.

To reconstitute Azithromycin 15 ml powder for suspension: Add 10 ml or 2 tea spoonfuls of just boiled and cooled water to the content of the bottle and shake well to mix uniformly.

To reconstitute Azithromycin 30 ml powder for suspension: Add 20 ml or 4 tea spoonfuls of just boiled and cooled water to the content of the bottle and shake well to mix uniformly.

To reconstitute Azithromycin 50 ml powder for suspension: Add 35 ml or 7 tea spoonfuls of just boiled and cooled water to the content of the bottle and shake well to mix uniformly.

Administration of Levofloxacin (solution for infusion) should be continued for a minimum of 48 to 72 hours after the patient has become febrile or evidence of bacterial eradication has been obtained. Levofloxacin solution for infusion is only intended for slow intravenous infusion; it is administered once or twice daily. The infusion time must be at least 30 minutes for 250 mg or 60 minutes for 500 mg Levofloxacin solution for infusion. It is possible to switch from an initial intravenous application to the oral route at the same dosage after a few days.

Side Effects

Azithromycin is well tolerated with a low incidence of side efects. The side effects include nausea, vomiting, abdominal discomfort (pain/cramps), flatulence, diarrhea, headache, dizziness, and skin rashes and are reversible upon discontinuation of therapy. Reversible elevations in liver transaminases have been observed occasionally. Transient mild reductions in neutrophil counts have occasionally been observed in clinical trials, although causal relationship to Azithromycin has not been established.

The most frequently reported adverse events were headache and a taste disturbance following instillation. Other adverse events included decreased/blurred vision, diarrhea, dyspepsia, fever, infection, instillation site irritation/discomfort, ocular infection, nausea, ocular pain/discomfort, and throat irritation.

Toxicity

Rat Oral LD50: >2000 mk/kg

Possible major adverse effects include cardiovascular arrhythmias and hearing loss. Macrolide resistance is also an ongoing issue. Hepatotoxicity has been observed in rare cases.

A note on the risk of liver toxicity:

Due to the act that azithromycin is mainly eliminated by the liver, caution should be observed when azithromycin is given to patients with decreased hepatic function .

A note on potential renal toxicity:

Because limited data in patients with renal GFR Label.

Use in Pregnancy:

This drug is categorized as a pregnancy category B drug. Reproduction studies have been done in rats and mice at doses up to moderately maternally toxic doses (for example, 200 mg/kg/day). These doses, based on a mg/m2 basis, are approximately 4 and 2 times, respectively, the human daily dose of 500 mg. In the animal studies, no harmful effects to the fetus due to azithromycin were observed. There are, at this time, no conclusive and well-controlled studies that have been done in pregnant women. Because animal reproduction studies do not always predict human response, azithromycin should be used during pregnancy only if clearly needed .

Nursing Mothers:

It is unknown at this time whether azithromycin is excreted in human milk. Because many other drugs are excreted in human milk, caution should be observed when azithromycin is given to a nursing woman .

Carcinogenesis, Mutagenesis, Impairment of Fertility:

Long-term studies in animals have not been performed to study carcinogenic potential. Azithromycin has demonstrated no potential to be mutagenic in standard laboratory tests. No evidence of negative effects on fertility due to azithromycin was found .

The LD₅₀ following oral administration in mice and rats is 1803 mg/kg and 1478 mg/kg, respectively.

Levofloxacin exhibits low potential for acute toxicity - following a single high dose of levofloxacin in several different test animals (e.g. mice, rats, monkeys) observed symptoms included ataxia, ptosis, decreased motor activity, dyspnea, tremors, and convulsions. Treatment of acute overdosage should involve stomach emptying (e.g. with activated charcoal) and general supportive measures. Consider monitoring of the patient's ECG to ensure QTc values remain within range. Levofloxacin is not efficiently removed by dialysis (peritoneal or hemodialysis) and is therefore of little benefit in cases of overdose.

Precaution

As with any antibiotic, observation for signs of super infection with non-susceptable organisms, including fungi, is recommended. Precaution should be taken in patients with more severe renal impairment.

The following measures should be taken during administration of Levofloxacin: While taking Levofloxacin adequate amount of water should be drunk to avoid risk of crystalluria. Dose adjustment should be exercised during Levofloxacin ingestion in presence of renal insufficiency & hepatic insufficiency.

While taking Levofloxacin adequate amount of water should be drunk to avoid risk of crystalluria. Dose adjustment should be exercised during Levofloxacin ingestion in presence of renal insufficiency & hepatic insufficiency.

Infusion of fluid should be immediately discontinued if rigor arises for any reason during the process. Do not use if the solution is cloudy, contains particles or after expiry date.

If an allergic reaction to levofloxacin occurs, discontinue the drug. Serious acute hypersensitivity reactions may require immediate emergency treatment. Oxygen and airway management should be administered as clinically indicated.

Prolonged use may result in overgrowth of non-susceptible organisms, including fungi. If superinfection occurs, discontinue use and institute alternative therapy. Patients should be advised not to wear contact lenses if they have signs and symptoms of corneal ulcer. Avoid contaminating the applicator tip with material from the eye, fingers or other source.

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 ergotism, concomitant administration of ergot derivatives and Azithromycin should be avoided. Digoxin & Cyclosporin: Macrolides have been known to increase the plasma concentration of Digoxin & Cyclosporin and so caution should be exercised while co-administration is necessary.

Anti-Histamines: A potentially life threatening interaction between erythromycin and terfenadine or astemizole have been reported. Although such an interaction with Azithromycin is not established yet, it is wise to avoid concomitant use of Azithromycin and terfenadine or astemizole.

Specific drug interaction studies have not been conducted with this drug. However, the systemic administration of some quinolones has been shown to elevate plasma concentrations of theophylline, interfere with the metabolism of caffeine, and enhance the effects of the oral anticoagulant warfarin and its derivatives, and has been associated with transient elevations in serum creatinine in patients receiving systemic cyclosporine concomitantly.

Volume of Distribution

After oral administration, azithromycin is widely distributed in tissues with an apparent steady-state volume of distribution of 31.1 L/kg . Significantly greater azithromycin concentrations have been measured in the tissues rather than in plasma or serum , . The lung, tonsils and prostate are organs have shown a particularly high rate of azithromycin uptake .

This drug is concentrated within macrophages and polymorphonucleocytes, allowing for effective activity against Chlamydia trachomatis . In addition, azithromycin is found to be concentrated in phagocytes and fibroblasts, shown by in vitro incubation techniques. In vivo studies demonstrate that concentration in phagocytes may contribute to azithromycin distribution to inflamed tissues .

Levofloxacin is widely distributed in the body, with an average volume of distribution following oral administration between 1.09-1.26 L/kg (~89-112 L). Concentrations in many tissues and fluids may exceed those observed in plasma. Levofloxacin is known to penetrate well into skin tissue, fluids (e.g. blisters), lung tissue, and prostatic tissue, amongst others.

Elimination Route

Bioavailability of azithromycin is 37% following oral administration. Absorption is not affected by food. Macrolide absorption in the intestines is believed to be mediated by P-glycoprotein (ABCB1) efflux transporters, which are known to be encoded by the ABCB1 gene .

Absorption of levofloxacin following oral administration is rapid and essentially complete, with an oral bioavailability of approximately 99%. Due to its nearly complete absorption, the intravenous and oral formulations of levofloxacin may be interchangeable. The T_max is generally attained 1-2 hours following administration and the C_max is proportional to the given dose - an intravenous dose of 500mg infused over 60 minutes resulted in a C_max of 6.2 ± 1.0 µg/mL whereas a 750mg dose infused over 90 minutes resulted in a C_max of 11.5 ± 4.0 µg/mL. Oral administration with food prolongs the T_max by approximately 1 hour and slightly decreases the C_max, but these changes are not likely to be clinically significant.

Systemic absorption following oral inhalation is approximately 50% lower than that observed following oral administration.

Half Life

Terminal elimination half-life: 68 hours

The average terminal elimination half-life of levofloxacin is 6-8 hours.

Clearance

Mean apparent plasma cl=630 mL/min (following single 500 mg oral and i.v. dose)

The average apparent total body clearance of levofloxacin ranges from 8.64-13.56 L/h, and its renal clearance ranges from 5.76-8.52 L/h. The relative similarity of these ranges indicates a small degree of non-renal clearance.

Elimination Route

Biliary excretion of azithromycin, primarily as unchanged drug, is a major route of elimination. Over a 1 week period, approximately 6% of the administered dose is found as unchanged drug in urine .

The majority of administered levofloxacin is excreted unchanged in the urine. Following the administration of a single oral dose of levofloxacin, approximately 87% was eliminated unchanged in the urine within 48 hours and less than 4% was eliminated in the feces within 72 hours.

Pregnancy & Breastfeeding use

Pregnancy: US FDA pregnancy category B. In the animal studies, no evidence of harm to the fetus due to Azithromycin was found. Because animal reproduction studies are not always predictive of human response, Azithromycin should be used during pregnancy only if clearly needed.

Lactation: It is not known whether Azithromycin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Azithromycin is administered to nursing mother.

Levofloxacin is not recommended for use during pregnancy or nursing, as the effects on the unborn child or nursing infant are unknown.

Contraindication

Azithromycin is contraindicated in patients hypersensitive to Azithromycin or any other macrolide antibiotic. Co-administration of ergot derivatives and Azithromycin is contraindicated. Azithromycin is contraindicated in patients with hepatic diseases.

Levofloxacin is contraindicated in patients with a history of hypersensitivity to Levofloxacin, quinolone antimicrobial agents, or any other components of this product.

Special Warning

Pediatric Use: Azithromycin oral dosage forms can be administered to pediatric patients from 6 months of age. Safety and effectiveness of azithromycin for injection in children or adolescents under 16 years have not been established.

Use in Children: From clinical studies, it is evident that Levofloxacin can be used in children aged as low as 6 months.The usual dose for children in community acquired pneumonia (CAP) is-

• Children aged 6 months to less than 5 years: 10 mg/kg b.i.d. (up to 500 mg per day) for 10 days.
• Children aged 5 years to 16 years: 10 mg/kg q.d. (up to 500 mg per day) for 10 days.

The usual dose for children in recurrent or persistent Acute Otitis Media (AOM) is Children aged 6 months to less than 5 years: 10 mg/kg per day (maximum dose: 500 mg/day) given twice daily for 10 days.

Acute Overdose

There are no data available on overdose with Azithromycin. Typical symptoms of overdosage with macrolide antibiotics include hearing loss, severe nausea, vomiting and diarrhoea. Gastric lavage and general supportive measures are indicated.

Levofloxacin exhibits a low potential for acute toxicity. However, in the events of an acute overdosage, the stomach should be emptied. The patients should be kept under observation and appropriate hydration should be maintained.

Storage Condition

Azithromycin IV infusion: When diluted according to the instructions, azithromycin for injection is stable for 24 hours at or below room temperature 30° C, or for 7 days if stored under refrigeration 5° C.

Azithromycin capsule, tablet and dry powder for suspension: should be stored at room temperature (below 30° C). Any unused portion of reconstituted Azithromycin suspension should be discarded after 5 days.

Azithromycin eye drops: Store unopened bottle under refrigeration at 2°C to 8°C. Once the bottle is opened, store at 2°C to 25°C for up to 14 days. Discard after the 14 days.

Store in a cool & dry place, protected from light. Keep out of the reach of children.

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