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DESCRIPTION:
Clarithromycin is a semi-synthetic derivative of erythromycin A. Chemically it is 6-O-methyl erythromycin. It is a new macrolide antimicorbial drug. It has broad spectrum of activity and is better absorbed than erythromycin and well tolerated and is to be administered less frequently. The minimum inhibitory concentrations (MICs) of clarithromycin are generally twofold lower than the Mic's of erythromycin. It is the most effective macrolide against Haemophillus influenzae, chlamydiatrachoma-tis and chlamydiapneumoniae.
MECHANISM OF ACTION:
It acts by binding to 50S ribosomal sub-unit of bacteria and inhibits the protein synthesis.
PHARMACOKINETICS:
After oral administration it is absorbed rapidly & is metabolized significantly in liver, which leads to reduced bio-availability. The 14-hydroxy metabolite has antimicrobial activity.
Onset of Action: 30-60 min.
Duration of Action: 8 to 12 hours
ADVERSE EFFECTS:
Nausea, vomiting dyspepsia, diarrhea, abdominal pain, headache, taste perversion, urticaria, anaphylaxis, Steven Johnson Syndrome, transient CNS symptoms like anxiety, dizziness, insomnia, confusion, bad dreams.
CONTRAINDICATIONS:
Hypersensitivity to Clarithromycin or any macrolide antibiotic.
Patients receiving terfenadine therapy who have pre-existing cardiac abnormalities or electrolyte disturbances.
SPECIAL PRECAUTIONS:Renal impairment.
PREGNANCY :
There are no well controlled studies in pregnant women, hence clarithromycin should not be used in pregnant women.
LACTATION:Use with caution as it is not known whether Clarithromycin is excreted in breast milk.
ELDERLY: May be used with caution
PAEDIATRIC USE:
The drug is not recommended for use in infants less than 6 months of age.
INTERACTIONS:
Terfenadine: Concomitant use may cause cardiac arrhythmia.
Carbamazepine & Theophylline: Concurrent use causes increase in serum levels of these drugs.
Zidovudine: In HIV infected patients steady state Zidovudine levels decreased.
Increased efficacy of the following drugs which are metabolised by the cytochrome P450 system: Digoxin, Warfarin, Ergot alkaloids, Triazolam, Midazolam and Cyclosporine.
INDICATIONS:
Claricin is indicated for the treatment of mild to moderate infections due to susceptible organisms.
Upper respiratory tract infections: Pharyngitis, Tonsillitis, Acute maxillary sinusitis, Acute otitis media.
Lower respiratory tract infection:Acute bronchitis, Acute exacerbations of chronic bronchitis, Community acquired pneumonia.
Skin soft tissue infection: Cellulitis, Folliculitis, Erysipelas, disseminated or localized mycobacterial infections, Legionella and Chlamydial infections. Eradication of helicobacter pylori.
DOSAGE AND ADMINISTRATION:
Adults: 250-500 mg twice a day for 7-14 days.
Eradication of helicobacter pylori: As combination therapy - ACT 10 i.e. Amoxycillin 500 mg BD + Clarithromycin 500 mg BD +Omeprazole 20 mg OD, all for 10 days.
Children: 15 mg/kg body weight into 2 divided doses for 7-14 days.
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