Description

Clar Tablet (Clarithromycin) – Product Information

Indications

Clar Tablet is an antibiotic used to treat various bacterial infections, including:

• Respiratory Tract Infections: Pharyngitis, tonsillitis, acute maxillary sinusitis, acute bacterial exacerbation of chronic bronchitis, pneumonia, community-acquired pneumonia, and legionellosis.
• Skin and Soft Tissue Infections
• Leprosy
• Peptic Ulcer Disease: Specifically for Helicobacter pylori eradication.
• Lyme Disease
• Acne

Dosage and Administration

Adults:

Oral Dosing:

• Acute Exacerbation of Chronic Bronchitis:
  • Standard Release: 250-500 mg orally every 12 hours for 7-14 days.
  • Extended Release: 1000 mg orally once daily for 7 days.
• Mycobacterial Infection (Prophylaxis and Treatment): 500 mg orally every 12 hours for 7-14 days. This should be used with other antimycobacterial drugs like rifampin and ethambutol.
• Peptic Ulcer Disease (Helicobacter pylori eradication): 500 mg orally every 8-12 hours for 10-14 days. Administer as part of a 2- or 3-drug combination regimen (e.g., with bismuth subsalicylate, amoxicillin, an H2 receptor antagonist, or a proton pump inhibitor).
• Pharyngitis, Tonsillitis: 250 mg orally every 12 hours for 10 days.
• Community-Acquired Pneumonia, Skin/Skin Structure Infection:
  • Standard Release: 250 mg orally every 12 hours for 7-14 days.
  • Extended Release: 1000 mg orally once daily for 7 days.
• Endocarditis Prophylaxis: 500 mg orally 30-60 minutes before a surgical procedure.

Intravenous (IV) Dosing:

• Respiratory Tract Infections; Skin and Soft Tissue Infections; Susceptible Infections: 500 mg twice daily for 2-5 days. Infuse over 60 minutes using a 0.2% solution. Switch to oral therapy as soon as possible.

Topical Dosing (for Acne, if applicable): Apply a thin layer to the affected area once daily.

Children:

• Oral Dosing: 15 mg/kg/day, divided and given every 12 hours. The maximum dose is 1 g/day.

Renal Dose:

• Creatinine Clearance (CrCl) <30 mL/min: Administer half the usual dosage or double the dosing interval.

Administration:

• Standard release tablets & oral suspension: Can be taken with or without food.
• XL (Extended Release) & MR (Modified Release) tablets: Should be taken with food. Swallow whole; do not chew or crush.

Contraindications

Do not use Clar Tablet if you have:

• Hypersensitivity to clarithromycin or other macrolide antibiotics.
• Are currently receiving terfenadine, astemizole, pimozide, cisapride, or ergot derivatives.
• Are pregnant (unless absolutely necessary and under strict medical supervision).
• A history of acute porphyria.

Precautions

• Use with caution in patients with renal and hepatic impairment.
• Be aware of potential macrolide cross-resistance.
• Lactation: The drug is excreted in breast milk; use with caution in nursing mothers.

Pregnancy and Lactation

• Pregnancy: Clarithromycin is generally contraindicated in pregnancy due to potential risks, unless the benefit clearly outweighs the risk and under strict medical guidance.
• Lactation: The drug is excreted in breast milk; use with caution.

Interactions

• Reduced efficacy: May occur with CYP3A inducers (e.g., phenytoin, carbamazepine).
• Lower plasma levels of clarithromycin: Strong inducers of the CYP450 system (e.g., efavirenz, rifampicin) may accelerate clarithromycin’s metabolism.
• Inhibition of metabolism: Occurs with ritonavir.
• Torsades de pointes: May result from concomitant use with quinidine or disopyramide.
• Increased phosphodiesterase inhibitor exposure: With sildenafil, tadalafil, or vardenafil.
• Increased risk of digoxin toxicity.
• Decreased concentration of zidovudine.
• Bi-directional drug interactions: Concomitant use with atazanavir, itraconazole, or saquinavir may result in complex drug interactions.
• Hypotension, bradyarrhythmias, and lactic acidosis: May result when taken with verapamil.
• Increased risk of myopathy, including rhabdomyolysis: With HMG-CoA reductase inhibitors (statins).
• Increased risk of hypoglycemia: With oral hypoglycemic drugs (e.g., pioglitazone) and insulin.
• Risk of serious hemorrhage and elevation of INR and prothrombin time: With oral anticoagulants.
• Increased ototoxicity: With aminoglycosides.
• Increased and prolonged sedation: With triazolobenzodiazepines (e.g., midazolam).

Potentially Fatal Interactions:

• Ergot alkaloids (e.g., ergotamine or dihydroergotamine): Concurrent use is associated with acute ergot toxicity, characterized by vasospasm and ischemia of the extremities.
• Astemizole, cisapride, pimozide, and terfenadine: Concomitant use may result in QT prolongation or serious ventricular cardiac arrhythmia.

Adverse Effects

Common (>10%):

• Gastrointestinal (GI) effects (general, 13%)

Frequent (1-10%):

• Abnormal taste (adults, 3-7%)
• Diarrhea (3-6%)
• Nausea (adults, 3-6%)
• Vomiting (adults, 1%; children, 6%)
• Elevated blood urea nitrogen (BUN; 4%)
• Abdominal pain (adults, 2%; children, 3%)
• Rash (children, 3%)
• Dyspepsia (2%)
• Heartburn (adults, 2%)
• Headache (2%)
• Elevated prothrombin time (PT; 1%)

Less Common (<1%):

• Anaphylaxis, Anorexia, Anxiety, Clostridium difficile colitis, Dizziness, Dyspnea, Elevated liver function tests, Glossitis, Hallucinations, Hepatic dysfunction, Hepatitis, Hypoglycemia, Increased alkaline phosphatase, Increased aspartate aminotransferase, Increased bilirubin, Increased serum creatinine, Jaundice, Leukopenia, Manic behavior, Neuromuscular blockade, Neutropenia, Pancreatitis, Psychosis, QT prolongation, Seizures, Stevens-Johnson syndrome, Thrombocytopenia.

Topical (for Acne):

• Dryness, irritation, itching, peeling, redness, swelling of the skin.

Potentially Fatal Adverse Effects:

• Pseudomembranous colitis, Anaphylaxis, Stevens-Johnson syndrome.

Mechanism of Action

Clarithromycin is a macrolide antibiotic. It works by inhibiting bacterial protein synthesis, binding to the 50S ribosomal subunits of susceptible organisms. It is effective against susceptible Streptococci and Staphylococci, as well as other species including B. catarrhalis, L. spp, C. trachomatis, and U. urealyticum.

Note:

Clar 250mg Tablet is manufactured by Hetero Drugs Ltd. Its generic name is Clarithromycin, and it is available in Nepal.