Doxtil Az

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

Cefpodoxime is used for the treatment of patients infected with susceptible strains of micro-organisms which include a wide range of gram-positive & gram-negative bacteria. As it is highly stable in presence of b-lactamase enzyme, so it is more effective against gram-positive bacteria than other 3rd generation oral Cephalosporins.

The susceptible organisms include gram-positive bacteria eg. S. aureus (including penicillinase producing strains), S. saprophyticus, S. pneumoniae, S. pyogenes, S. agalactiae, P. magnus and gram-negative bacteria eg. E. coli, K. pneumoniae, H. influenzae (including b-lactamase producer & Ampicillin resistant strains), M. catarrhalis, N. gonorrhoeae (including penicillinase producing strains), P. mirabillis, C. diversus, H. parainfluenzae, K. oxytoca, P. vulgaris, P. rettgeri.

Ximeprox is used for the following diseases:-

(1) Lower respiratory tract infection: Acute community-acquired pneumonia, Acute bacterial exacerbation of chronic bronchitis; (2) Upper respiratory tract infection: Acute otitis media, Acute maxillary sinusitis, Pharyngitis, Tonsillitis; (3) Sexually transmitted diseases: Acute uncomplicated urethral & cervical gonorrhea, Acute ano-rectal infection in woman caused by N. gonorrhoeae; (4) Uncomplicated urinary tract infection: Cystitis, Pyuria; (5) Skin & soft tissue infections: Furuncle, Cellulitis, Subcutaneous abscess, infectious atheroma & periproctal abscess (6) Enteric fever.

Doxtil Az 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, UrethritisAcute Bacterial Exacerbation of Chronic Bronchitis (ABECB), Acute Otitis Media, Acute Sinusitis, Acute Tracheobronchitis, Acute maxillary sinusitis, Bacterial Infections, Bacterial Pneumonia, Community Acquired Pneumonia (CAP), Gonorrhea, Lower Respiratory Tract Infection (LRTI), Otitis Media (OM), Pharyngitis, Skin and Soft Tissue Infections, Streptococcal Pharyngitis, Streptococcal tonsillitis, Superinfection bacterial, Tonsillitis, Uncomplicated Urinary Tract Infections, Upper Respiratory Tract Infection, Uncomplicated Lower Respiratory Tract Infection (LRTI), Uncomplicated Upper Respiratory Tract Infection, Uncomplicated Urethritis gonococcal, Uncomplicated skin and subcutaneous tissue bacterial infections

How Doxtil Az 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 .

Cefpodoxime is active against a wide spectrum of Gram-positive and Gram-negative bacteria. Cefpodoxime is stable in the presence of beta-lactamase enzymes. As a result, many organisms resistant to penicillins and cephalosporins, due to their production of beta-lactamase, may be susceptible to cefpodoxime. Cefpodoxime is inactivated by certain extended spectrum beta-lactamases. The bactericidal activity of cefpodoxime results from its inhibition of cell wall synthesis. The active metabolite of cefpodoxime binds preferentially to penicillin binding protein 3, which inhibits production of peptidoglycan, the primary constituent of bacterial cell walls.

Dosage

Doxtil Az 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.

Ximeprox should be administered orally with food to enhance absorption. Ximeprox suspension may be given without regard to food.

Child :

15 days - 6 months : 4 mg/kg every 12 hours

6 months - 2 years : 40 mg every 12 hours

3 - 8 years : 80 mg every 12 hours

over 9 years : 100 mg every 12 hours

Patients with renal dysfunction: For patients with severe renal impairment (creatinine clearance <30 ml/min) the dosing intervals should be increased to 24 hourly.

Patients with liver cirrhosis: Cefpodoxime proxetil pharmacokinetics in cirrhotic patients are similar to those in healthy subjects. Dose adjustment is not necessary in this population.

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.

Direction for Reconstitution of suspension:

For 100 ml suspension : Add 50 ml (10 measuring spoonful) of boiled and cooled water to the dry mixture in the bottle. For ease of preparation add water to the bottle in two portions. Shake well after each addition until all the powder is in suspension.

For 50 ml suspension : Add 25 ml (5 measuring spoonful) of boiled and cooled water to the dry mixture in the bottle. For ease of preparation add water to the bottle in two portions. Shake well after each addition until all the powder is in suspension.

For 50 ml DS suspension : Add 25 ml (5 measuring spoonful) of boiled and cooled water to the dry mixture in the bottle. For ease of preparation add water to the bottle in two portions. Shake well after each addition until all the powder is in suspension.

Note: Shake the suspension well before each use. Keep the bottle tightly closed. The reconstituted suspension should be stored in a cool and dry place, preferably in refrigerator and unused portion should be discarded after 10 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.

Cefpodoxime has very few side effects. The side effects include diarrhea, nausea, skin & vaginal fungal infection, abdominal pain, headache, chest pain, myalgia, dyspepsia, dizziness, vertigo, cough etc. In children incidence of fungal skin rash is more than adults.

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 .

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.

In patients with transient or persistent reduction in urinary output due to renal insufficiency, the total daily dose of cefpodoxime proxetil should be reduced. Cefpodoxime, like other cephalosporins, should be administered with caution to patients receiving concurrent treatment with potent diuretics. As with other broad spectrum antibiotics, prolonged use of cefpodoxime proxetil may result in overgrowth of non-susceptible organisms. Repeated evaluation of the patient's condition is essential.

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.

Antacids or H2-blockers may decrease the absorption of cefpodoxime. Reduced renal excretion with probenecid.

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 .

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 .

Cefpodoxime proxetil is a prodrug that is absorbed from the gastrointestinal tract and de-esterified to its active metabolite, cefpodoxime. Following oral administration of 100 mg of cefpodoxime proxetil to fasting subjects, approximately 50% of the administered cefpodoxime dose was absorbed systemically.

Half Life

Terminal elimination half-life: 68 hours

2.09 to 2.84 hours

Clearance

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

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 .

Over the recommended dosing range (100 to 400 mg), approximately 29 to 33% of the administered cefpodoxime dose was excreted unchanged in the urine in 12 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.

There are no adequate and well-controlled studies on Cefpodoxime proxetil use in pregnant woman, but it was found neither teratogenic nor embryocidal in animal trial. However, the drug should be used during pregnancy only if clearly needed. In nursing mother, Cefpodoxime is excreted in breast milk & there is potential risk of serious reactions in nursing infants, so a decision should be made whether to discontinue breast feeding or to discontinue the drug.

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.

Cefpodoxime is contraindicated in patients with known allergy to the cephalosporin class of antibiotics.

Renal Impairment: Patients with renal dysfunction: For patients with severe renal impairment (creatinine clearance <30 ml/min) the dosing intervals should be increased to 24 hourly.

Hepatic Impairment: The dosage does not require modification in cases of hepatic impairment.

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.

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.

Symptoms: Nausea, vomiting, epigastric distress and diarrhoea.

Management: Haemodialysis or peritoneal dialysis may be useful in the event of a serious toxic reaction particularly if renal function is compromised.

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.

Capsule: Store below 30° C, protected from light and moisture.

Powder for suspension: Store below 25° C, protected from light and moisture.

After reconstitution: The suspension can be used within 7 days if be kept at room temperature and within 14 days if be kept in refrigerator (2° to 8° C). Always keep the bottle tightly closed.

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