Clarithromycin is indicated for the treatment of the following conditions:

• Acute bacterial exacerbation of chronic bronchitis in adults
• Acute maxillary sinusitis
• Community-acquired pneumonia
• Pharyngitis or tonsillitis
• Uncomplicated skin and skin structure infections
• Acute otitis media in pediatric patients
• Treatment and prophylaxis of disseminated mycobacterial infections
• Helicobacter pylori infection and duodenal ulcer disease in adults

Clarithromycin works by inhibiting protein synthesis in susceptible organisms. It mainly binds to the donor site on the 50S subunit of the bacterial ribosome and prevents translocation at that site. Clarithromycin is active against most Gram-positive bacteria and Chlamydia, as well as some Gram-negative bacteria and Mycoplasma. In vitro, clarithromycin has activity that is equal to or greater than erythromycin against most Gram-positive bacteria. Clarithromycin is more acid-stable than erythromycin and is therefore generally better tolerated. It has approximately twice the activity of erythromycin against H. influenzae. Most species of Gram-negative bacteria are resistant to clarithromycin because the drug fails to penetrate the target site effectively.

Adults:

• Acute bacterial exacerbation of chronic bronchitis: 250 mg to 500 mg every 12 hours for 7 to 14 days.
• Acute maxillary sinusitis: 500 mg every 12 hours for 14 days.
• Community-acquired pneumonia: 250 mg every 12 hours for 7 to 14 days.
• Pharyngitis or tonsillitis: 250 mg every 12 hours for 10 days.
• Uncomplicated skin and skin structure infections: 250 mg every 12 hours for 7 to 14 days.  বাংলায় দেখুন
• Treatment and prophylaxis of disseminated Mycobacterium avium disease: 500 mg every 12 hours until the patient is considered at low risk of disseminated infection.

Combination dosing regimens for H. pylori infection:

Triple therapy: Clarithromvcin/lansoprazole/amoxicillin: The recommended adult dosage is 500 mg clarithromycin, 30 mg lansoprazole and 1 g amoxicillin, all given every 12 hours for 10 or 14 days.

Triple therapy: Clarithromycin/omeprazole/amoxicillin: The recommended adult dosage is 500 mg clarithromycin, 20 mg omeprazole and 1 g amoxicillin; all given every 12 hours for 10 or 14 days. In patients with an ulcer present at the time of initiation of therapy, an additional 14 or 18 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief.

Dual therapy: Clarithromycin/omeprazole: The recommended adult dosage is 500 mg clarithromycin given every 8 hours and 40 mg omeprazole given once every morning for 14 days. An additional 14 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief.

Children: The recommended daily dosage is 15 mg/kg/day divided every 12 hours for 10 days. For treatment and prophylaxis of mycobacterial infections in pediatric patients, the recommended dose is 7.5 mg/kg every 12 hours up to 500 mg every 12 hours.

Renal and hepatic impairment: Clarithromycin is principally excreted via the liver and kidney. Clarithromycin may be administered without dosage adjustment to patients with hepatic impairment and normal renal function. However, in the presence of severe renal impairment with or without coexisting hepatic impairment, decreased dosaqe or prolonqed dosinq intervals may be appropriate.

Clarithromycin may interact with several medications and should not be used together with certain drugs. Concomitant use with HMG-CoA reductase inhibitors such as lovastatin and simvastatin is contraindicated due to the increased risk of serious side effects. It should also not be taken with gastroprokinetic agents like cisapride, ergot alkaloids such as ergotamine and dihydroergotamine, antipsychotic medicines including pimozide and quetiapine, and anti-gout drugs such as colchicine. In addition, the combined use of clarithromycin with certain antiarrhythmic medications like disopyramide, quinidine, dofetilide, amiodarone, sotalol and procainamide is generally not recommended because it may increase the risk of heart rhythm problems.

Clarithromycin should not be used in patients who are allergic to clarithromycin, erythromycin, other macrolide antibiotics, or any ingredient of this medicine. It is also contraindicated in patients who previously developed cholestatic jaundice or liver dysfunction related to the use of clarithromycin.

Clarithromycin is generally well tolerated by most patients. However, some people may experience side effects such as nausea, vomiting, diarrhea and abdominal discomfort. In some cases, inflammation of the mouth (stomatitis) and tongue (glossitis) has been reported. Other possible side effects include headache and allergic reactions ranging from mild skin rash or urticaria to severe reactions like anaphylaxis. Altered taste sensation may also occur. Rarely, temporary central nervous system effects such as anxiety, dizziness, insomnia and hallucinations have been reported.

Clarithromycin may be used in newborns and children when given in appropriate doses under medical supervision. However, infants should not be fed breast milk from mothers who are taking clarithromycin until the treatment course is completed. There is limited clinical experience regarding the use of clarithromycin during pregnancy; therefore, its use in pregnant women is generally not recommended unless clearly necessary.

Clarithromycin should be stopped immediately if a patient develops severe acute hypersensitivity reactions. It should be used with caution and generally avoided in patients with known QT interval prolongation or those taking medicines that can prolong the QT interval. Patients with ventricular arrhythmia, low potassium (hypokalemia), low magnesium (hypomagnesemia), significant slow heart rate (bradycardia), or those receiving Class IA or Class III antiarrhythmic drugs should avoid using this medicine. Treatment should also be discontinued if symptoms or signs of hepatitis appear. Studies have shown an increased risk of overall mortality one year or more after treatment in patients with coronary artery disease. Therefore, physicians should carefully weigh the potential risks and benefits before prescribing clarithromycin to these patients. If diarrhea develops during treatment, the patient should be evaluated for Clostridium difficile–associated diarrhea (CDAD). In some cases, worsening of myasthenia gravis symptoms has been reported in patients treated with clarithromycin.

Use in children and adolescents: The safety and effectiveness of clarithromycin have been confirmed for treating conditions such as pharyngitis, tonsillitis, community-acquired pneumonia, acute maxillary sinusitis, acute otitis media, and uncomplicated skin and soft tissue infections in pediatric patients aged 6 months and older. Clarithromycin has also been shown to be safe and effective for the prevention of disseminated Mycobacterium avium complex (MAC) disease in children aged 20 months and older who have advanced HIV infection. However, the safety of clarithromycin has not been studied in MAC patients younger than 20 months. In addition, the safety and effectiveness of clarithromycin in infants below 6 months of age have not yet been established.

Taking an excessive amount of clarithromycin may lead to gastrointestinal symptoms such as nausea, vomiting, and abdominal discomfort. In one reported case, a patient with a history of bipolar disorder ingested 8 grams of clarithromycin and developed symptoms including altered mental status, paranoid behavior, low potassium levels (hypokalemia), and low oxygen levels in the blood (hypoxemia). Management of overdose should include rapid removal of any unabsorbed drug along with supportive medical treatment. Similar to other macrolide antibiotics, clarithromycin blood levels are not significantly reduced by hemodialysis or peritoneal dialysis.

Macrolide Antibiotic

Store the medicine in a cool and dry place, protected from light and moisture. After reconstitution, the suspension should be used within 7 days if stored at room temperature or within 14 days if kept in a refrigerator. Always keep the medicine out of the reach of children.