Roxithromycin; Uses, Dosage, Side Effects, Drug Interactions

Semisynthetic derivative of erythromycin. Roxithromycin is concentrated by human phagocytes and is bioactive intracellularly. While the drug is active against a wide spectrum of pathogens, it is particularly effective in the treatment of respiratory and genital tract infections.

Roxithromycin is a semi-synthetic macrolide antibiotic. It is very similar in composition, chemical structure and mechanism of action to erythromycin, azithromycin, or clarithromycin. Roxithromycin prevents bacteria from growing, by interfering with their protein synthesis. Roxithromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides. Roxithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly Legionella pneumophila. It can treat respiratory tract, urinary and soft tissue infections.

Mechanism of Action of Roxithromycin

Roxithromycin prevents bacteria from growing, by interfering with their protein synthesis. Roxithromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the synthesis of peptides. Roxithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly Legionella pneumophila.Roxithromycin has the following antibacterial spectrum in vitro: Streptococcus agalactiae, Streptococcus pneumoniae (Pneumococcus), Neisseria meningitides (Meningococcus), Listeria monocytogenes, Mycoplasma pneumoniae, Chlamydia trachomatis, Ureaplasma urealyticum, Legionella pneumophila, Helicobacter (Campylobacter), Gardnerella vaginalis, Bordetella pertussis, Moraxella catarrhalis (Branhamella Catarrhalis), and Haemophilus ducreyi. Roxithromycin is highly concentrated in polymorphonuclear leukocytes and macrophages, achieving intracellular concentrations greater than those outside the cell. Roxithromycin enhances the adhesive and chemotactic functions of these cells which in the presence of infection? produce phagocytosis and bacterial lysis. Roxithromycin also possesses intracellular bactericidal activity.

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Roxithromycin is a semi-synthetic derivative of the macrolide antibiotic erythromycin that includes an N-oxime side chain on the lactone ring, with antibacterial and anti-malarial activities. Roxithromycin binds to the subunit 50S of the bacterial ribosome, which inhibits bacterial protein synthesis and leads to inhibition of bacterial cell growth and replication.

Indications of Roxithromycin

• Mycoplasma Pneumonia
• Sinusitis?
• Bronchitis?
• acute? bronchitis (infection of the bronchi causing coughing)
• pneumonia (lung infection characterised by fever, malaise, headache)
• skin and soft tissue infections
• non gonococcal urethritis
• impetigo (bacterial infection causing sores on the skin).
• Nongonococcal Urethritis
• Pharyngitis
• Pneumonia
• Skin and Structure Infection
• Skin or Soft Tissue Infection
• Strep Throat?
• Tonsillitis/Pharyngitis
• Toxoplasmosis
• Upper Respiratory Tract Infection
• Used to treat respiratory tract, urinary and soft tissue infections.

Contra-Indications of Roxithromycin

• Allergic to roxithromycin or to any of the other ingredients in roxithromycin tablets or to drugs like erythromycin, azithromycin, or clarithromycin
• Diarrhea with blood in stools
• Porphyria
• It should not be used with colchicine in people with kidney? or liver? impairment.

Dosages of Roxithromycin

The recommended dosage? for adults is 300 mg per day.

You may take this according to one of the following dosage regimens:

• one 300 mg tablet once a day, or
• one 150 mg tablet twice a day, or
• two 150 mg tablets once a day.

The dose for a child will depend on this child’s weight.

The recommended dose for children weighing 40 kg and more is 150 mg twice a day.

Roxithromycin AN should not be used for children less than 40 kg in weight.

Side Effects of Roxithromycin

The most common

• Nausea and vomiting
• Severe? stomach ache
• epigastric pain
• diarrhoea,
• anorexia,
• flatulence
• headache,
• dizziness,

 Common

• Nausea and vomiting
• Severe stomach ache
• Severe diarrhea
• Mouth sores
• Vaginal thrush
• Skin rash
• Headache
• Ringing or buzzing in the ears
• Decreased appetite

Serious

• Porphyria
• Gastrointestinal: abdominal cramps, nausea?, diarrhea, anorexia, pancreatitis?
• Genitourinary: vulvovaginal candidiasis, renal failure?
• Cardiovascular System: prolongation of QT interval
• Hepatic: hepatotoxicity, jaundice?
• Hematologic: eosinophilia?, thrombocytosis, lymphopenia
• Central Nervous System  a headache, fatigue
• Endocrine/Metabolic, hyperglycemia
• Dermatologic: itching, nail discoloratiom

Drug Interactions of Roxithromycin

Roxithromycin has fewer interactions than erythromycin as it has a lower affinity for cytochrome P450. Roxithromycin does not interact with hormonal contraceptives, prednisolone, carbamazepine, ranitidine or antacids. When roxithromycin is administered with theophylline, some studies have shown an increase in the plasma concentration of theophylline. A change in dosage is usually not required but patients with high levels of theophylline at the start of the treatment should have their plasma levels monitored.

• terfenadine and astemizole, medicines used to treat allergies
• digoxin, a medicine used to treat heart failure?
• midazolam, a medicine used to induce sleep before operations
• cyclosporin, a medicine used to prevent organ transplant rejection or to treat certain problems with the immune system
• cisapride, a medicine used to treat gastrointestinal problems
• pimozide, an antipsychotic medicine.

Roxithromycin appears to interact with warfarin. This is shown by an increase in prothrombin time? and/or international normalised ratio (INR?) in patients taking roxithromycin and warfarin concurrently. As a consequence, severe bleeding episodes have occurred.

Pregnancy & Lactation of Roxithromycin

Pregnancy Category B1

B1 catagory drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed.

Pregnancy

Erythromycin is still the drug of choice among the macrolides during pregnancy. Erythromycin estolate and troleandomycin should not be given in the second and third trimesters. Newer macrolides such as azithromycin, clarithromycin, josamycin, and roxithromycin are second-choice macrolides.

Lactation

Breastfeeding or treatment of the mother should be discontinued as necessary. Use in the Elderly. No dosage adjustment is required in elderly patients. Carcinogenesis and Mutagenesis. Long-term studies in animals have not been performed to evaluate the carcinogenic potential of roxithromycin.

References