Each film-coated tablet contains Clarithromycin 500 mg.
Pharmacology: Clarithromycin is a semisynthetic macrolide antibiotic with activity against many gram-positive and gram-negative aerobic and anaerobic organisms. Clarithromycin usually is bacteriostatic, although it may be bactericidal in high concentrations or against highly susceptible organisms such as S. pyogenes, S. pneumoniae, H. influenzae and Chlamydia trachomatis. Clarithromycin inhibits protein synthesis in susceptible organisms by penetrating the cell wall and binding to 50S ribosomal subunits, thereby inhibiting translocation of aminoacyl transfer-RNA and inhibiting polypeptide synthesis. Clarithromycin is absorbed rapidly from the GI tract after oral administration with an absolute bioavailability of approximately 50-55%. Food delays the rate, but not the extent of absorption. The drug undergoes extensive first-pass metabolism. Clarithromycin and its active metabolite are widely distributed into most body tissues and fluid except the CSF. Concentrations in tissues are higher than in serum. It is 42-72% bound to plasma protein. Clarithromycin is metabolized in the liver, prinicipally by oxidative N-demethylation, hydroxylation, and hydrolysis to metabolites. One metabolite, 14-hydroxyclarithromycin, has antimicrobial activity comparable to clarithromycin and may act synergistically with the drug against H. influenzae. The elimination half-life of clarithromycin are 3-4 hours and 5-7 hours following 250 and 500 mg dose; the half-life of 14-hydroxyclarithromycin are 5-6 hours with 250 mg dose and 7-9 hours with 500 mg dose. Approx, 20 and 30%, respectively, of the dose of 250 and 500 mg tablets given every 12 hours is excreted unchanged in urine within 12 hours. The principal metabolite, 14-hydroxyclarithromycin, which accounts for approx. 10-15% of the dose is excreted in urine after a 250 and 500 mg dose every 12 hours.
The serum half-life of clarithromycin is prolonged in patients with impaired renal function. The reduction of clarithromycin dosage may be required if creatinine clearance is less than 30 mL/min.
Treatment of infections caused by susceptible microorganisms e.g., upper and lower respiratory tract infections, skin and soft tissue infections.
Use in combination with other antimycobacterials for the treatment of Mycobacterium avium complex (MAC) infections.
Use in combination with other drugs for the treatment of Helicobacter pylori infection in patients with duodenal ulcer.
Adults: Mild to moderate respiratory or skin and soft tissue infections: Oral, 250 mg every twelve hours for 7-14 days.
Mild to moderate acute maxillary sinusitis: Oral, 500 mg every twelve hours for 14 days.
Acute exacerbation of chronic bronchitis caused by H. influenzae: Oral, 500 mg every twelve hours for 7-14 days.
Disseminated MAC infections: Oral, 500 mg every twelve hours, in combination with other antimycobacterials.
H. pylori infections: Oral, 500 mg three times daily for 14 days, in combination with other drugs, Dual Therapy.
It is contraindicated in patients with known hypersensitive to clarithromycin, erythromycin, or any other macrolides.
Concomitant administration of clarithromycin and any of the following drugs is contraindicated: terfenadine, astemizole, cisapride, and pimozide because clarithromycin has been reported to alter the metabolism resulting on increased levels and cardiac arrhythmias effects.
Should not prescribe clarithromycin to pregnant women, particularly during the first three months of pregnancy.
Should be considered before using clarithromycin in nursing women without carefully weighing the benefits against risk because clarithromycin is excreted into human breast milk.
Should be used with caution in patient with hepatic impairment or moderated to severe renal impairment.
Use in Pregnancy: Should not prescribe clarithromycin to pregnant women, particularly during the first three months of pregnancy.
Use in Lactation: Should be considered before using clarithromycin in nursing women without carefully weighing the benefits against risk because clarithromycin is excreted into human breast milk.
Clarithromycin generally is well tolerated. Most adverse effects are mild and transient and usually resolve following discontinuance of the drug. The common adverse effect is GI effects such as diarrhea, nausea, vomiting, abnormal taste, dyspepsia, and abdominal discomfort. Other side effects included headache, anxiety, vertigo, insomnia, confusion, bad dreams, hallucination, and transient elevations of liver enzymes. Allergic reactions e.g., urticaria, rash, pruritus have been reported. Anaphylaxis and Stevens-Johnson Syndrome may occur rarely. Isolated cases of leukopenia and thrombocytopenia have been reported. Pseudomembranous colitis has been reported with nearly all antibacterial agents, including macrolides.
Concomitant use of clarithromycin and drugs metabolized by the cytochrome P-450 (CYP) system may be associated with increased serum concentrations of the latter drugs, and serum concentrations of such concomitantly administered drugs should be monitored closely.
Concomitant use of clarithromycin with cisapride, pimozide, terfenadine, or astemizole, is contraindicated because of QT prolongation and serious cardiovascular effects.
Concurrent use of clarithromycin with ergot alkaloids (ergotamine, dihydroergotamine) is contraindicated due to acute ergot toxicity, vasospasm and ischemia of the extremities and other tissues, including the CNS.
Clarithromycin should be used with caution in patients receiving carbamazepine. A reduction in carbamazepine, dosage and/or monitoring plasma carbamazepine concentrations is advised.
Clarithromycin has been reported to increase serum concentrations of HMG-CoA reductase inhibitor (e.g., lovastatin, simvastatin) via inhibition of metabolism by cytochrome-P450 isoenzymes.
Concomitant use of clarithromycin and rifabutin or rifampicin increases the metabolism of clarithromycin. This leads to decrease serum clarithromycin concentrations >50%.
Concurrent use of clarithromycin with oral anticoagulants may potentiate the effects of the oral anticoagulant, so prothrombin time must be monitored carefully in patients receiving such concomitant therapy.
CNS effects (e.g., somnolence, confusion) have been reported when clarithromycin was used concomitantly with triazolam.
Elevated serum concentrations of digoxin have been reported in patients receiving digoxin and clarithromycin concomitantly, monitoring of digoxin serum concentrations is recommended in such patients.
Clarithromycin has been shown to increase serum theophylline concentrations. Therefore, patients receiving clarithromycin concomitantly with high doses of theophylline or in those with theophylline serum concentrations in the upper therapeutic range should be monitored serum theophylline concentrations. Theophylline dosage should be adjusted if necessary when clarithromycin is added or withdrawn in a patient receiving theophylline.
Concurrent administration with antiretroviral agents: Concomitant use of clarithromycin and atazanavir results in an increased peak plasma concentrations and AUC of both drugs. Clarithromycin dosage should be reduced by 50% in patients receiving atazanavir.
Concomitant use of clarithromycin with delavirdine causes a 100% increase in the AUC of clarithromycin. Concurrent administration with the fixed combination of lopinavir and ritonavir may result in an increased clarithromycin concentrations. In addition, ritonavir has been found to increase peak plasma concentrations and AUC of clarithromycin but decrease those of clarithromycin active metabolite. Modification of the usual dosage of clarithromycin is not necessary in patients with normal renal function. However, the dose should be reduced by 50% in patients with creatinine clearances of 30-60 mL/minute and reduced by 75% in individuals with creatinine clearances less than 30 mL/minute.
Administration of clarithromycin and efavirenz decreases peak plasma concentration and AUC of clarithromycin but increases those of clarithromycin active metabolite. Because rash develops in 46% of individual receiving such concomitant therapy, alternatives to clarithromycin (e.g., azithromycin) and monitoring for macrolide efficacy should be considered.
Concurrent use of clarithromycin with saquinavir may result in increased plasma concentrations of both drugs. Dosage adjustments may not be needed if clarithromycin and saquinavir are used concomitantly for a limited time at the dosage studies (clarithromycin 600 mg twice daily and saquinavir 1.2 g 3 times daily).
In well-closed container, below 25°C. Protect from light.
J01FA09 - clarithromycin ; Belongs to the class of macrolides. Used in the systemic treatment of infections.
FC tab 500 mg x 5 x 14's.