Klaricid: Formula, Presentation, Indications, Mechanism of Action, Dosage, Side Effects and Interactions

Its active ingredient is Clarithromycin, a semisynthetic antibiotic from the group of macrolides.

Clarithromycin is obtained by substituting the CH3O group for the hydroxyl group (OH) at position 6 of the lactone ring of erythromycin.

This drug is indicated to treat skin, breast, and respiratory tract infections.

Chemical formula

  • C38H69NO13.


The presentation of the Klaricid is:

  • Prolonged-release tablets of 250 and 500 mg.
  • Pediatric suspension of 125 and 250 mg / 5 mL.


Clarithromycin is a drug indicated for the treatment of infections such as:

  • Lower respiratory tract infections such as bronchitis, pneumonia, upper respiratory tract infections such as pharyngitissinusitis , and diseases of the skin and soft tissues such as folliculitiscellulitis, and erysipelas.
  • Localized or disintegrated mycobacterial infections caused by Mycobacterium avium or Mycobacterium intracellulare.
  • Localized infections are caused by Mycobacterium chelonae, Mycobacterium fortuitum, or Mycobacterium kansasii.
  • Clarithromycin is indicated to prevent complex infections caused by Mycobacterium avium in patients infected with AIDS with a CD4 + lymphocyte count less than or equal to 100 / mm3.
  • Clarithromycin is also indicated in the treatment of H. pylori, whose eradication decreases duodenal ulcers.

Mechanism of action

The mechanism of action of Clarithromycin is performed by inhibiting the protein synthesis of sensitive bacteria by binding to 50s ribosomal subunits.

The macrolides bind to a protein called L4 that is part of the peptidyl site, thus interfering with the elongation at the level of the translocation phase.


In this phase, the recently synthesized peptidyl tRNA molecule moves from the acceptor site in the ribosome to the peptidyl site, thus exerting its antibacterial function.


The usually recommended dose of Klaricid in adults is a 250 mg tablet every 12 hours.

In those more severe infections, the dose can be increased to 500 mg every 12 hours.

Generally, the duration of treatment is from 5 to 14 days, excluding the treatment of pneumonia and sinusitis, which requires therapy lasting 6 to 14 days.

In those patients with kidney problems, the dose of Klaricid should be reduced by half, 250 mg every 24 hours or 250 mg every 12 hours, in cases of more severe infections.

The treatment should never be prolonged for more than 14 days in this type of patient.

The recommended dose in patients with mycobacterial infections in adults is 500 mg every 12 hours.

Clarithromycin should be used in conjunction with other antimycobacterial agents.

To prevent the Mycobacterium Avium Complex, the recommended dose of clarified in adults is 500 mg every 12 hours.

In the case of dental infections, the dose of klaricid recommended for treatment is 250 mg tablet every 12 hours for five days.

For the elimination of H. pylori, the recommended regimens are:

  • Triple therapy regimen: Administer Klaricid 500 mg every 12 hours, with lansoprazole, 30 mg or omeprazole 20 mg every 12 hours, and amoxicillin 1000 mg every 12 hours, for ten days.
  • Dual therapy regimens: Klaricid 500 mg every 8 hours and lansoprazole 60 mg or omeprazole 20 to 40 mg daily for 14 days.

Children’s recommended pediatric suspension doses are 7.5 mg per kilogram of body weight every 12 hours, with a maximum dose of 500 mg every 12 hours for 5 to 10 days.

In the treatment for streptococcal pharyngitis, the duration of therapy should not be less than ten days.

In those children with kidney problems, the dose should be reduced by half to 250 mg. every 24 hours or, in severe infections, 250 mg. every 12 hours without exceeding the treatment for more than 14 days.

In children who contract mycobacterial infections, the dose is 15 to 30 mg per kg of body weight divided into two daily doses every 12 hours.

The pediatric dosage based on body weight is 7.5 mg/kg every 12 hours.

Side effects

The most frequent adverse reactions related to the treatment of Klaricid are abdominal pain, diarrhea, nausea, vomiting, and taste alteration.

These secondary reactions are generally of low intensity and are consistent with what is presented in the safety profile of macrolide antibiotics.

Reports of toxicity were presented with the concomitant use of Klaricid and Colchicine, especially in older adults; some of these toxicities occurred in patients with renal insufficiency.

Warnings and contraindications

Klaricid is contraindicated in patients who report known hypersensitivity to macrolide-type antibiotics.

Klaricid and any of the following drugs should not be administered concomitantly:

Astemizole, cisapride, pimozide, terfenadine and ergotamine or dihydroergotamine.

The clarified is excreted through the liver and kidney. Therefore, caution should be exercised when administering the antibiotic to patients with liver function problems.

Caution should also be exercised when administered in patients with moderate to severe renal dysfunction.

There is a possibility of cross-resistance between the Klaricid and other macrolide drugs, such as lincomycin and clindamycin.

During pregnancy, its use should be restricted since there are no adequate and well-controlled studies on pregnant women.

The klaricid should only be administered during pregnancy if the drug’s potential benefits significantly outweigh the risks that may occur in the fetus.

As for breastfeeding, research has shown that this drug is excreted in breast milk, so it should be administered with caution during lactation.

In pediatric use, for children under six months, the safety and effectiveness of the Klaricid are not established.

The safety of Klaricid has not been studied in patients under 20 months of age in the cases of the Mycobacterium Avium Complex.

In geriatric use, a study in which healthy elderly (aged between 65 and 81 years) who were administered Klaricid, the maximum blood concentration of Clarithromycin was observed to increase compared to those reached in healthy young adults.

These changes are related to age.

An adjustment of the dose should be considered in those elderly patients who present a severe renal compromise.

Prolonged use of Klaricid, as with other antibiotics, can result in bacteria and fungal resistance and weaken the immune system.

If a severe infection occurs, appropriate therapy should be established to avoid these effects.

An increase in the symptoms of myasthenia gravis has been reported in those patients who were administered the Klaricid.


Some drugs are strictly contraindicated due to the interaction effects that they manifest with the concomitant use of the Klaricid.

Elevated levels of cisapride have been reported in patients receiving Klaricid concomitantly. This association can prolong the QT interval, ventricular tachycardia, cardiac arrhythmias, ventricular fibrillation, and a specific abnormal heart rhythm called torsades de pointes.

Similar effects have been reported in patients receiving concomitant clarified and pimozide.

It has been reported that this type of macrolide antibiotic modifies the metabolism of terfenadine.

It is causing an increase in levels of the latter, which is occasionally associated with cardiac arrhythmias: prolongation of the QT interval, ventricular tachycardia, ventricular fibrillation, and symptoms such as palpitations, dizziness, lightheadedness, and even sudden cardiac death caused by the torsades. Of pointes.

In reports of coadministration of Klaricid with ergotamine or dihydroergotamine, they have been associated with acute toxicity due to the presence of ergot, which is characterized by causing vasospasm and ischemia in the extremities and other tissues, including the Central Nervous System.

Therefore, its use for this administration of Klaricid and these medicinal products is contraindicated concomitantly.

Some drugs are known or suspected to affect the circulating concentrations of Clarithromycin, which may require adjustment of the Klaricid dose or consideration of other alternative treatments.

Drugs such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine are potent stimulants of the metabolic system of cytochrome P450 proteins.

These can accelerate the metabolism of Clarithromycin and therefore decrease its levels in the blood.

In this way, the levels of 14 (R) -hydroxiclaritromycin (14-OH-clarithromycin), a metabolite that is also microbiologically active, are increased.

But these compounds have different microbiological activities from other bacteria.

The desired therapeutic effect may be altered during the concomitant administration of Klaricid and this group of enzyme stimulants.

Ritonavir administered concomitantly with Klaricid results in a marked inhibition of metabolism of the latter, and in patients with kidney problems, a dose adjustment should be considered.