- 1. Name of the medicinal product
- 2. Qualitative and quantitative composition
- 3. Pharmaceutical form
- 4. Clinical particulars
- 4.1 Therapeutic indications
- 4.2 Posology and method of administration
- 4.3 Contraindications
- 4.4 Special warnings and precautions for use
- 4.5 Interaction with other medicinal products and other forms of interaction
- 4.6 Pregnancy and lactation
- 4.7 Effects on ability to drive and use machines
- 4.8 Undesirable effects
- 4.9 Overdose
- 5. Pharmacological properties
- 5.1 Pharmacodynamic properties
- 5.2 Pharmacokinetic properties
- 5.3 Preclinical safety data
- 6. Pharmaceutical particulars
- 6.1 List of excipients
- 6.2 Incompatibilities
- 6.3 Shelf life
- 6.4 Special precautions for storage
- 6.5 Nature and contents of container
- 6.6 Special precautions for disposal and other handling
- 7. Marketing authorisation holder
- 8. Marketing authorisation number(s)
- 9. Date of first authorisation/renewal of the authorisation
- 10. Date of revision of the text
Patients with respiratory tract/skin and soft tissue infections.Adults: The usual dose is 250 mg twice daily although this may be increased to 500mg twice daily in severe infections. The usual duration of treatment is 6 to 14 days. Children older than 12 years: As for adults. Children younger than 12 years: Use of Klaricid 500mg Tablets are not recommended for children younger than 12 years. Clinical trials have been conducted using clarithromycin paediatric suspension in children 6 months to 12 years of age. Therefore, children under 12 years of age should use clarithromycin paediatric suspension (granules for oral suspension). Eradication of H. pylori in patients with duodenal ulcers (Adults) The usual duration of treatment is 6 to 14 days.Triple Therapy Clarithromycin (500mg) twice daily and lansoprazole 30mg twice daily should be given with amoxycillin 1000mg twice daily.Triple Therapy Clarithromycin (500mg) twice daily and lansoprazole 30mg twice daily should be given with metronidazole 400mg twice daily. Triple Therapy Clarithromycin (500mg) twice daily and omeprazole 40mg daily should be given with amoxycillin 1000mg twice daily or metronidazole 400mg twice daily. Triple Therapy Clarithromycin (500mg) twice daily should be given with amoxycillin 1000mg twice daily and omeprazole 20mg daily. Dual Therapy The usual dose of Clarithromycin is 500 mg three times daily for 14 days. Clarithromycin should be administered with oral omeprazole 40 mg once daily. The pivotal study was conducted with omeprazole 40 mg once daily for 28 days. Supportive studies have been conducted with omeprazole 40 mg once daily for 14 days. For further information on the dosage for omeprazole see the Astra data sheet. Elderly: As for adults.Renal impairment:In patients with renal impairment with creatinine clearance less than 30 mL/min, the dosage of clarithromycin should be reduced by one-half, i.e. 250 mg once daily, or 250 mg twice daily in more severe infections. Treatment should not be continued beyond 14 days in these patients. Clarithromycin may be given without regard to meals as food does not affect the extent of bioavailability.
The use of the following drugs is strictly contraindicated due to the potential for severe drug interaction effects:
Cisapride, pimozide, astemizole and terfenadine:Elevated cisapride levels have been reported in patients receiving clarithromycin and cisapride concomitantly. This may result in QT prolongation and cardiac arrhythmias including ventricular tachycardia, ventricular fibrillation and torsades de pointes. Similar effects have been observed in patients taking clarithromycin and pimozide concomitantly (see section 4.3).Macrolides have been reported to alter the metabolism of terfenadine resulting in increased levels of terfenadine which has occasionally been associated with cardiac arrhythmias, such as QT prolongation, ventricular tachycardia, ventricular fibrillation and torsades de pointes (see section 4.3). In one study in 14 healthy volunteers, the concomitant administration of clarithromycin and terfenadine resulted in 2- to 3-fold increase in the serum level of the acid metabolite of terfenadine and in prolongation of the QT interval which did not lead to any clinically detectable effect. Similar effects have been observed with concomitant administration of astemizole and other macrolides.
Ergotamine/dihydroergotamine:Post-marketing reports indicate that co-administration of clarithromycin with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm, and ischaemia of the extremities and other tissues including the central nervous system. Concomitant administration of clarithromycin and these medicinal products is contraindicated (see section 4.3).
HMG-CoA Reductase Inhibitors (statins)Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated (see 4.3) as these statins are extensively metabolized by CYP3A4 and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Reports of rhabdomyolysis have been received for patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment.Caution should be exercised when prescribing clarithromycin with statins. In situations where the concomitant use of clarithromycin with statins cannot be avoided, it is recommended to prescribe the lowest registered dose of the statin. Use of a statin that is not dependent on CYP3A metabolism (e.g.fluvastatin) can be considered. Patients should be monitored for signs and symptoms of myopathy.
Effects of Other Medicinal Products on ClarithromycinDrugs that are inducers of CYP3A (e.g. rifampicin, phenytoin, carbamazepine, phenobarbital, St John's wort) may induce the metabolism of clarithromycin. This may result in sub-therapeutic levels of clarithromycin leading to reduced efficacy. Furthermore, it might be necessary to monitor the plasma levels of the CYP3A inducer, which could be increased owing to the inhibition of CYP3A by clarithromycin (see also the relevant product information for the CYP3A4 inhibitor administered). Concomitant administration of rifabutin and clarithromycin resulted in an increase in rifabutin, and decrease in clarithromycin serum levels together with an increased risk of uveitis.The following drugs are known or suspected to affect circulating concentrations of clarithromycin; clarithromycin dosage adjustment or consideration of alternative treatments may be required.
Efavirenz, nevirapine, rifampicin, rifabutin and rifapentineStrong inducers of the cytochrome P450 metabolism system such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine may accelerate the metabolism of clarithromycin and thus lower the plasma levels of clarithromycin, while increasing those of 14-OH-clarithromycin, a metabolite that is also microbiologically active. Since the microbiological activities of clarithromycin and 14-OH-clarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers.
EtravirineClarithromycin exposure was decreased by etravirine; however, concentrations of the active metabolite, 14-OH-clarithromycin, were increased. Because 14-OH-clarithromycin has reduced activity against Mycobacterium avium complex (MAC), overall activity against this pathogen may be altered; therefore alternatives to clarithromycin should be considered for the treatment of MAC.
FluconazoleConcomitant administration of fluconazole 200 mg daily and clarithromycin 500 mg twice daily to 21 healthy volunteers led to increases in the mean steady-state minimum clarithromycin concentration (Cmin) and area under the curve (AUC) of 33% and 18% respectively. Steady state concentrations of the active metabolite 14-OH-clarithromycin were not significantly affected by concomitant administration of fluconazole. No clarithromycin dose adjustment is necessary.
RitonavirA pharmacokinetic study demonstrated that the concomitant administration of ritonavir 200 mg every eight hours and clarithromycin 500 mg every 12 hours resulted in a marked inhibition of the metabolism of clarithromycin. The clarithromycin Cmax increased by 31%, Cmin increased 182% and AUC increased by 77% with concomitant administration of ritonavir. An essentially complete inhibition of the formation of 14-OH-clarithromycin was noted. Because of the large therapeutic window for clarithromycin, no dosage reduction should be necessary in patients with normal renal function. However, for patients with renal impairment, the following dosage adjustments should be considered: For patients with CLCR 30 to 60 mL/min the dose of clarithromycin should be reduced by 50%. For patients with CLCR <30 mL/min the dose of clarithromycin should be decreased by 75%. Doses of clarithromycin greater than 1 gm/day should not be co-administered with ritonavir.Similar dose adjustments should be considered in patients with reduced renal function when ritonavir is used as a pharmacokinetic enhancer with other HIV protease inhibitors including atazanavir and saquinavir (see section below, Bi-directional drug interactions).
Effect of Clarithromycin on Other Medicinal Products
CYP3A-based interactionsCo-administration of clarithromycin, known to inhibit CYP3A, and a drug primarily metabolised by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug. Clarithromycin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g. carbamazepine) and/or the substrate is extensively metabolised by this enzyme.Dosage adjustments may be considered, and when possible, serum concentrations of drugs primarily metabolised by CYP3A should be monitored closely in patients concurrently receiving clarithromycin.The following drugs or drug classes are known or suspected to be metabolised by the same CYP3A isozyme: alprazolam, astemizole, carbamazepine, cilostazol, cisapride, ciclosporin, disopyramide, ergot alkaloids, lovastatin, methylprednisolone, midazolam, omeprazole, oral anticoagulants (e.g. warfarin, see 4.4), pimozide, quinidine, rifabutin, sildenafil, simvastatin, sirolimus, tacrolimus, terfenadine, triazolam and vinblastine. Drugs interacting by similar mechanisms through other isozymes within the cytochrome P450 system include phenytoin, theophylline and valproate.
AntiarrhythmicsThere have been post-marketed reports of torsades de pointes occurring with the concurrent use of clarithromycin and quinidine or disopyramide. Electrocardiograms should be monitored for QT prolongation during co-administration of clarithromycin with these drugs. Serum levels of quinidine and disopyramide should be monitored during clarithromycin therapy.There have been post marketing reports of hypoglycemia with the concomitant administration of clarithromycin and disopyramide. Therefore blood glucose levels should be monitored during concomitant administration of clarithromycin and disopyramide.
Oral hypoglycemic agents/InsulinWith certain hypoglycemic drugs such as nateglinide, and repaglinide, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypolgycemia when used concomitantly. Careful monitoring of glucose is recommended.
OmeprazoleClarithromycin (500 mg every 8 hours) was given in combination with omeprazole (40 mg daily) to healthy adult subjects. The steady-state plasma concentrations of omeprazole were increased (Cmax, AUC0-24, and t1/2 increased by 30%, 89%, and 34%, respectively), by the concomitant administration of clarithromycin. The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when omeprazole was co-administered with clarithromycin.
Sildenafil, tadalafil and vardenafilEach of these phosphodiesterase inhibitors is metabolised, at least in part, by CYP3A, and CYP3A may be inhibited by concomitantly administered clarithromycin. Co-administration of clarithromycin with sildenafil, tadalafil or vardenafil would likely result in increased phosphodiesterase inhibitor exposure. Reduction of sildenafil, tadalafil and vardenafil dosages should be considered when these drugs are co-administered with clarithromycin.
Theophylline, carbamazepineResults of clinical studies indicate that there was a modest but statistically significant (p≤ 0.05) increase of circulating theophylline or carbamazepine levels when either of these drugs were administered concomitantly with clarithromycin. Dose reduction may need to be considered.
TolterodineThe primary route of metabolism for tolterodine is via the 2D6 isoform of cytochrome P450 (CYP2D6). However, in a subset of the population devoid of CYP2D6, the identified pathway of metabolism is via CYP3A. In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine. A reduction in tolterodine dosage may be necessary in the presence of CYP3A inhibitors, such as clarithromycin in the CYP2D6 poor metaboliser population.
Triazolobenzodiazepines (e.g., alprazolam, midazolam, triazolam)When midazolam was co-administered with clarithromycin tablets (500 mg twice daily), midazolam AUC was increased 2.7-fold after intravenous administration of midazolam and 7-fold after oral administration. Concomitant administration of oral midazolam and clarithromycin should be avoided. If intravenous midazolam is co-administered with clarithromycin, the patient must be closely monitored to allow dose adjustment. The same precautions should also apply to other benzodiazepines that are metabolised by CYP3A, including triazolam and alprazolam. For benzodiazepines which are not dependent on CYP3A for their elimination (temazepam, nitrazepam, lorazepam), a clinically important interaction with clarithromycin is unlikely.There have been post-marketing reports of drug interactions and central nervous system (CNS) effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested.
Other drug interactionsAminoglycosidesCaution is advised regarding concomitant administration of clarithromycin with other ototoxic drugs, especially with aminoglycosides. See 4.4.ColchicineColchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. When clarithromycin and colchicine are administered together, inhibition of Pgp and/or CYP3A by clarithromycin may lead to increased exposure to colchicine. Patients should be monitored for clinical symptoms of colchicine toxicity (see section 4.4).
DigoxinDigoxin is thought to be a substrate for the efflux transporter, P-glycoprotein (Pgp). Clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are administered together, inhibition of Pgp by clarithromycin may lead to increased exposure to digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have also been reported in post marketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Serum digoxin concentrations should be carefully monitored while patients are receiving digoxin and clarithromycin simultaneously.
ZidovudineSimultaneous oral administration of clarithromycin tablets and zidovudine to HIV-infected adult patients may result in decreased steady-state zidovudine concentrations. Because clarithromycin appears to interfere with the absorption of simultaneously administered oral zidovudine, this interaction can be largely avoided by staggering the doses of clarithromycin and zidovudine to allow for a 4-hour interval between each medication. This interaction does not appear to occur in paediatric HIV-infected patients taking clarithromycin suspension with zidovudine or dideoxyinosine. This interaction is unlikely when clarithromycin is administered via intravenous infusion.
Phenytoin and ValproateThere have been spontaneous or published reports of interactions of CYP3A inhibitors, including clarithromycin with drugs not thought to be metabolised by CYP3A (e.g. phenytoin and valproate). Serum level determinations are recommended for these drugs when administered concomitantly with clarithromycin. Increased serum levels have been reported.
Bi-directional drug interactions
AtazanavirBoth clarithromycin and atazanavir are substrates and inhibitors of CYP3A, and there is evidence of a bi-directional drug interaction. Co-administration of clarithromycin (500 mg twice daily) with atazanavir (400 mg once daily) resulted in a 2-fold increase in exposure to clarithromycin and a 70% decrease in exposure to 14-OH-clarithromycin, with a 28% increase in the AUC of atazanavir. Because of the large therapeutic window for clarithromycin, no dosage reduction should be necessary in patients with normal renal function. For patients with moderate renal function (creatinine clearance 30 to 60 mL/min), the dose of clarithromycin should be decreased by 50%. For patients with creatinine clearance <30 mL/min, the dose of clarithromycin should be decreased by 75% using an appropriate clarithromycin formulation. Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors.Calcium Channel BlockersCaution is advised regarding the concomitant administration of clarithromycin and calcium channel blockers metabolized by CYP3A4 (e.g. verapamil, amlodipine, diltiazem) due to the risk of hypotension. Plasma concentrations of clarithromycin as well as calcium channel blockers may increase due to the interaction. Hypotension, bradyarrhythmias and lactic acidosis have been observed in patients taking clarithromycin and verapamil concomitantly.ItraconazoleBoth clarithromycin and itraconazole are substrates and inhibitors of CYP3A, leading to a bidirectional drug interaction. Clarithromycin may increase the plasma levels of itraconazole, while itraconazole may increase the plasma levels of clarithromycin. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged pharmacologic effect.
SaquinavirBoth clarithromycin and saquinavir are substrates and inhibitors of CYP3A, and there is evidence of a bi-directional drug interaction. Concomitant administration of clarithromycin (500 mg twice daily) and saquinavir (soft gelatin capsules, 1200 mg three times daily) to 12 healthy volunteers resulted in steady-state AUC and Cmax values of saquinavir which were 177% and 187% higher than those seen with saquinavir alone. Clarithromycin AUC and Cmax values were approximately 40% higher than those seen with clarithromycin alone. No dose adjustment is required when the two drugs are co-administered for a limited time at the doses/formulations studied. Observations from drug interaction studies using the soft gelatin capsule formulation may not be representative of the effects seen using the saquinavir hard gelatin capsule. Observations from drug interaction studies performed with saquinavir alone may not be representative of the effects seen with saquinavir/ritonavir therapy. When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (see section 4.5: Ritonavir).Clarithromycin has been shown not to interact with oral contraceptives.
a. Summary of the safety profileThe most frequent and common adverse reactions related to clarithromycin therapy for both adult and paediatric populations are abdominal pain, diarrhoea, nausea, vomiting and taste perversion. These adverse reactions are usually mild in intensity and are consistent with the known safety profile of macrolide antibiotics (see section b of section 4.8).There was no significant difference in the incidence of these gastrointestinal adverse reactions during clinical trials between the patient population with or without pre-existing mycobacterial infections.
b. Tabulated summary of adverse reactionsThe following table displays adverse reactions reported in clinical trials and from post-marketing experience with clarithromycin immediate-release tablets, granules for oral suspension, powder for solution for injection, extended-release tablets and modified-release tablets.The reactions considered at least possibly related to clarithromycin are displayed by system organ class and frequency using the following convention: very common (≥1/10), common (≥ 1/100 to < 1/10), uncommon (≥1/1,000 to < 1/100) and not known (adverse reactions from post-marketing experience; cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness when the seriousness could be assessed.
|System Organ Class||Very common ≥1/10||Common ≥ 1/100 to < 1/10||Uncommon ≥1/1,000 to < 1/100||Not Known* (cannot be estimated from the available data)|
|Infections and infestations||Cellulitis1, candidiasis, gastroenteritis2, infection3, vaginal infection||Pseudomembranous colitis, erysipelas,|
|Blood and lymphatic system||Leukopenia, neutropenia4, thrombocythaemia3, eosinophilia4||Agranulocytosis, thrombocytopenia|
|Immune system disorders5||Anaphylactoid reaction1, hypersensitivity||Anaphylactic reaction. angioedema|
|Metabolism and nutrition disorders||Anorexia, decreased appetite|
|Psychiatric disorders||Insomnia||Anxiety, nervousness3, screaming3||Psychotic disorder, confusional state, depersonalisation, depression, disorientation, hallucination, abnormal dreams|
|Nervous system disorders||Dysgeusia, headache, taste perversion||Loss of consciousness1, dyskinesia1, dizziness, somnolence6, tremor||Convulsion, ageusia, parosmia, anosmia, paraesthesia|
|Ear and labyrinth disorders||Vertigo, hearing impaired, tinnitus||Deafness|
|Cardiac disorders||Cardiac arrest1, atrial fibrillation1, electrocardiogram QT prolonged7, extrasystoles1, palpitations||Torsades de pointes7, ventricular tachycardia7|
|Respiratory, thoracic and mediastinal disorder||Asthma1, epistaxis2, pulmonary embolism1|
|Gastrointestinal disorders||Diarrhoea9, vomiting, dyspepsia, nausea, abdominal pain||Oesophagitis1, gastrooesophageal reflux disease2, gastritis, proctalgia2, stomatitis, glossitis, abdominal distension4, constipation, dry mouth, eructation, flatulence,||Pancreatitis acute, tongue discolouration, tooth discolouration|
|Hepatobiliary disorders||Liver function test abnormal||Cholestasis4, hepatitis4, alanine aminotransferase increased, aspartate aminotransferase increased, gamma-glutamyltransferase increased4||Hepatic failure10, jaundice hepatocellular|
|Skin and subcutaneous tissue disorders||Rash, hyperhidrosis||Dermatitis bullous1, pruritus, urticaria, rash maculo-papular3||Stevens-Johnson syndrome5, toxic epidermal necrolysis5, drug rash with eosinophilia and systemic symptoms (DRESS), acne|
|Musculoskeletal and connective tissue disorders||Muscle spasms3, musculoskeletal stiffness1, myalgia2||Rhabdomyolysis2,11**, myopathy|
|Renal and urinary disorders||Blood creatinine increased1, blood urea increased1||Renal failure, nephritis interstitial|
|General disorders and administration site conditions||Injection site phlebitis1||Injection site pain1, injection site inflammation1||Malaise4, pyrexia3, asthenia, chest pain4, chills4, fatigue4|
|Investigations||Albumin globulin ratio abnormal1, blood alkaline phosphatase increased4, blood lactate dehydrogenase increased4||International normalised ratio increased8, prothrombin time prolonged8, urine colour abnormal|
c. Description of selected adverse reactionsInjection site phlebitis, injection site pain, vessel puncture site pain, and injection site inflammation are specific to the clarithromycin intravenous formulation.In some of the reports of rhabdomyolysis, clarithromycin was administered concomitantly with statins, fibrates, colchicine or allopurinol (see section 4.3 and 4.4).There have been post-marketing reports of drug interactions and central nervous system (CNS) effects (e.g. somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested (see section 4.5).There have been rare reports of clarithromycin ER tablets in the stool, many of which have occurred in patients with anatomic (including ileostomy or colostomy) or functional gastrointestinal disorders with shortened GI transit times. In several reports, tablet residues have occurred in the context of diarrhoea. It is recommended that patients who experience tablet residue in the stool and no improvement in their condition should be switched to a different clarithromycin formulation (e.g. suspension) or another antibiotic.Special population: Adverse Reactions in Immunocompromised Patients (see section e).
d. Paediatric populationsClinical trials have been conducted using clarithromycin paediatric suspension in children 6 months to 12 years of age. Therefore, children under 12 years of age should use clarithromycin paediatric suspension. There are insufficient data to recommend a dosage regimen for use of the clarithromycin IV formulation in patients less than 18 years of age.Frequency, type and severity of adverse reactions in children are expected to be the same as in adults.e. Other special populations
Immunocompromised patientsIn AIDS and other immunocompromised patients treated with the higher doses of clarithromycin over long periods of time for mycobacterial infections, it was often difficult to distinguish adverse events possibly associated with clarithromycin administration from underlying signs of Human Immunodeficiency Virus (HIV) disease or intercurrent illness.In adult patients, the most frequently reported adverse reactions by patients treated with total daily doses of 1000 mg and 2000mg of clarithromycin were: nausea, vomiting, taste perversion, abdominal pain, diarrhoea, rash, flatulence, headache, constipation, hearing disturbance, Serum Glutamic Oxaloacetic Transaminase (SGOT) and Serum Glutamic Pyruvate Transaminase (SGPT) elevations. Additional low-frequency events included dyspnoea, insomnia and dry mouth. The incidences were comparable for patients treated with 1000mg and 2000mg, but were generally about 3 to 4 times as frequent for those patients who received total daily doses of 4000mg of clarithromycin.In these immunocompromised patients, evaluations of laboratory values were made by analysing those values outside the seriously abnormal level (i.e. the extreme high or low limit) for the specified test. On the basis of these criteria, about 2% to 3% of those patients who received 1000mg or 2000mg of clarithromycin daily had seriously abnormal elevated levels of SGOT and SGPT, and abnormally low white blood cell and platelet counts. A lower percentage of patients in these two dosage groups also had elevated Blood Urea Nitrogen levels. Slightly higher incidences of abnormal values were noted for patients who received 4000mg daily for all parameters except White Blood Cell.
ATC Classification:Pharmacotherapeutic group: Antibacterial for systemic use, macrolideATC-Code: J01FA09
Mode of Action:Clarithromycin is an antibiotic belonging to the macrolide antibiotic group. It exerts its antibacterial action by selectively binding to the 50s ribosomal sub-unit of susceptible bacteria preventing translocation of activitate amino acids. It inhibits the intracellular protein synthesis of susceptible bacteria.The 14-hydroxy metabolite of clarithromycin, a product of parent drug metabolism also has antimicrobial activity. The metabolite is less active than the parent compound for most organisms, including mycobacterium spp. An exception is Haemophilus influenza where the 14-hydroxy metabolite is two-fold more active than the parent compound.Clarithromycin is usually active against the following organisms in vitro:Gram-positive Bacteria: Staphylococcus aureus (methicillin susceptible); Streptococcus pyogenes (Group A beta-hemolytic streptococci) alpha-hemolytic streptococci (viridans group); Streptococcus (Diplococcus) pneumoniae; Streptococcus agalactiae; Listeria monocytogenes.Gram-negative Bacteria: Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella (Branhamella) catarrhalis, Neisseria gonorrhoeae; Legionella pneumophila, Bordetella pertussis, Helicobacter pylori; Campylobacter jejuni.Mycoplasma: Mycoplasma pneumoniae; Ureaplasma urealyticum.Other Organisms: Chlamydia trachomatis; Mycobacterium avium, Mycobacterium leprae; Mycobacterum kansasii; Mycobacterium chelonae; Mycobacterium fortuitum; Mycobacterium intracellulare.Anaerobes: Macrolide-susceptible Bacteroides fragilis, Clostridium perfringens; Peptococcus species; Peptostreptococcus species; Propionibacterium acnes.Clarithromycin has bactericidal activity against several bacterial strains. The organisms include Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Moraxella (Branhamella) catarrhalis, Neisseria gonorrhoeae, H. pylori and Campylobacter spp.
BreakpointsThe following breakpoints have been established by the European Committee for Antimicrobial Susceptibility Testing (EUCAST).
|Breakpoints (MIC, mg/L)|
|Microorganism||Susceptible (≤)||Resistant (>)|
|Staphylococcus spp.||1 mg/L||2 mg/L|
|Streptococcus A, B, C and G||0.25 mg/L||0.5 mg/L|
|Streptococcus pneumonia||0.25 mg/L||0.5 mg/L|
|Viridans group streptococcus||IE||IE|
|Haemophilus spp.||1 mg/L||32 mg/L|
|Moraxella catarrhalis||0.25 mg/L||0.5 mg/L 1|
|Helicobacter pylori||0.25 mg/L1||0.5 mg/L|
|1 The breakpoints are based on epidemiological cut-off values (ECOFFs), which distinguish wild-type isolates from those with reduces susceptibility. IE" indicates that there is insufficient evidence that the species in question is a good target for therapy with the drug.|
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