Clasrin
Generic Name
Clarithromycin
Manufacturer
Square Pharmaceuticals Ltd.
Country
Bangladesh
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Description
Overview of the medicine
Clarithromycin is a macrolide antibiotic used to treat various bacterial infections, including respiratory tract infections, skin infections, and Helicobacter pylori infections.
Uses & Indications
Dosage
Adults
Typically 250-500 mg twice daily for 7-14 days, depending on the infection. For H. pylori eradication, 500 mg twice daily for 7-14 days in combination.
Elderly
No specific dose adjustment typically required unless severe renal impairment.
Renal_impairment
Dosage reduction may be necessary in patients with severe renal impairment (CrCl < 30 mL/min), e.g., 250 mg once daily or half the usual dose.
How to Take
Clarithromycin can be taken orally with or without food. For best absorption and to reduce gastrointestinal upset, it is often recommended to take it with food. Do not crush or chew extended-release tablets.
Mechanism of Action
Clarithromycin inhibits bacterial protein synthesis by reversibly binding to the 50S ribosomal subunit of susceptible bacteria, thereby preventing translocation of peptides.
Pharmacokinetics
Onset
Onset of action is typically within hours.
Excretion
Excreted through urine (20-40%) and feces (30-40%).
Half life
Approximately 3-7 hours for the parent drug and 5-9 hours for the active metabolite (14-hydroxyclarithromycin).
Absorption
Rapidly absorbed from the gastrointestinal tract, bioavailability is approximately 50-55%.
Metabolism
Extensively metabolized in the liver via the cytochrome P450 3A (CYP3A) enzyme system.
Side Effects
Contraindications
- Known hypersensitivity to clarithromycin or other macrolide antibiotics
- History of cholestatic jaundice/hepatic dysfunction associated with clarithromycin
- Co-administration with cisapride, pimozide, astemizole, terfenadine due to risk of QT prolongation and cardiac arrhythmias
- Co-administration with colchicine in patients with renal or hepatic impairment
- Co-administration with ergotamine or dihydroergotamine due to risk of ergot toxicity
Drug Interactions
Warfarin
Increased anticoagulant effect, monitor INR.
Colchicine
Increased colchicine toxicity, especially in renal/hepatic impairment.
QT-prolonging drugs
Increased risk of cardiac arrhythmias.
Statins (e.g., lovastatin, simvastatin)
Increased risk of myopathy/rhabdomyolysis due to CYP3A inhibition.
Pimozide, Terfenadine, Astemizole, Cisapride
Contraindicated due to severe cardiac effects.
Storage
Store below 30°C in a dry place, away from light. Keep out of reach of children.
Overdose
Symptoms of overdose include gastrointestinal symptoms like nausea, vomiting, abdominal pain, and diarrhea. Management typically involves gastric lavage and supportive care. Hemodialysis and peritoneal dialysis are not effective.
Pregnancy & Lactation
Pregnancy Category C. Use only if clearly needed and potential benefits outweigh risks. Clarithromycin is excreted in breast milk; caution should be exercised when administered to a nursing woman.
Side Effects
Contraindications
- Known hypersensitivity to clarithromycin or other macrolide antibiotics
- History of cholestatic jaundice/hepatic dysfunction associated with clarithromycin
- Co-administration with cisapride, pimozide, astemizole, terfenadine due to risk of QT prolongation and cardiac arrhythmias
- Co-administration with colchicine in patients with renal or hepatic impairment
- Co-administration with ergotamine or dihydroergotamine due to risk of ergot toxicity
Drug Interactions
Warfarin
Increased anticoagulant effect, monitor INR.
Colchicine
Increased colchicine toxicity, especially in renal/hepatic impairment.
QT-prolonging drugs
Increased risk of cardiac arrhythmias.
Statins (e.g., lovastatin, simvastatin)
Increased risk of myopathy/rhabdomyolysis due to CYP3A inhibition.
Pimozide, Terfenadine, Astemizole, Cisapride
Contraindicated due to severe cardiac effects.
Storage
Store below 30°C in a dry place, away from light. Keep out of reach of children.
Overdose
Symptoms of overdose include gastrointestinal symptoms like nausea, vomiting, abdominal pain, and diarrhea. Management typically involves gastric lavage and supportive care. Hemodialysis and peritoneal dialysis are not effective.
Pregnancy & Lactation
Pregnancy Category C. Use only if clearly needed and potential benefits outweigh risks. Clarithromycin is excreted in breast milk; caution should be exercised when administered to a nursing woman.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Typically 24 to 36 months from manufacturing date.
Availability
Available in pharmacies and hospitals
Approval Status
Approved by FDA/DGDA
Patent Status
Off-patent
WHO Essential Medicine
YesClinical Trials
Extensive clinical trials have established the efficacy and safety of clarithromycin for various bacterial infections since its approval in 1991. Ongoing research focuses on its role in emerging antimicrobial resistance patterns.
Lab Monitoring
- Liver function tests (LFTs) in patients with pre-existing hepatic impairment
- Renal function tests if dosage adjustment is required
- INR for patients on warfarin
Doctor Notes
- Assess renal and hepatic function before initiating treatment, especially in elderly patients.
- Be aware of significant drug interactions, particularly with CYP3A inhibitors/substrates and QT-prolonging agents.
- Educate patients on the importance of completing the full course and potential side effects.
Patient Guidelines
- Complete the full course of antibiotics, even if symptoms improve.
- Do not share this medication with others.
- Inform your doctor about all other medications and supplements you are taking.
- Report any severe or persistent side effects to your doctor.
Missed Dose Advice
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not double the dose to catch up.
Driving Precautions
Clarithromycin may cause dizziness, confusion, or visual disturbances in some patients. Advise patients to use caution when driving or operating machinery until they know how the medication affects them.
Lifestyle Advice
- Maintain good hydration.
- Avoid alcohol, especially if experiencing stomach upset.
- Practice good hygiene to prevent further spread of infection.
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International brand names for this medicine. Click a brand to search for detailed information.
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