Clarithromycin

Pharmaceuticals -> Listed in ZINC15

Pharmaceuticals -> Antibiotics

Pharmaceuticals -> Antibiotics (Macrolides)

Pharmaceuticals -> Used in Switzerland

log Kow = 3.16

1.7

3.16

Breast Feeding; Lactation; Anti-Bacterial Agents; Anti-Infective Agents; Macrolides

FDA approved drugs -> Active ingredient

FDA approved drugs -> Active ingredient

Pharmaceuticals

Watch group antibiotics

217-220 °C (decomposes) ... Also reported as mp 222-225 °C

217 - 220 °C

Positive

5.3

2.7

Agilent XCT

Electrospray ionization

formic acid (5.3nM)

8.99

8.99 (at 25 °C)

pKa = 8.99

Warning

H302 (99.2%): Harmful if swallowed [Warning Acute toxicity, oral]

P264, P270, P301+P317, P330, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 243 reports by companies from 11 notifications to the ECHA C&L Inventory.

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

Hazard Traits - Developmental Toxicity

Clarithromycin: Does not have an individual approval but may be used under an appropriate group standard

The Approved Drug Products with Therapeutic Equivalence Evaluations identifies currently marketed prescription drug products, including clarithromycin, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

Acute Tox. 4 (99.2%)

Acute toxicity (Oral) - Category 4

As with all fires, evacuate personnel to a safe area. Firefighters should use self-contained breathing equipment and protective clothing.

Water spray, dry chemical, carbon dioxide, or foam as appropriate for surrounding fire and materials.

Store in tight container as defined in the USP-NF. This material should be handled and stored per label instructions to ensure product integrity.

Clarithromycin granules for oral suspension should be stored in well-closed containers at 15-30 °C. Following reconstitution as directed, oral suspensions of clarithromycin should be stored at 15-30 °C in well-closed containers; the reconstituted suspension should not be refrigerated.

Commercially available clarithromycin 250-mg conventional tablets should be stored in well-closed containers at 15-30 °C and should be protected from light.1 Clarithromycin 500-mg conventional tablets should be stored in well- closed containers at controlled room temperature between 20-25 det C. Clarithromycin extended-release tablets should be stored at 20-25 °C, but may be exposed to temperatures ranging from 15-30 °C.

Wear approved respiratory protection, chemically compatible gloves, and protective clothing. Wipe up spillage or collect spillage using a high-efficiency vacuum cleaner. Avoid breathing dust. Place spillage in appropriately labeled container for disposal. Wash spill site.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

SRP: Expired or waste pharmaceuticals shall carefully take into consideration applicable DEA, EPA, and FDA regulations. It is not appropriate to dispose by flushing the pharmaceutical down the toilet or discarding to trash. If possible return the pharmaceutical to the manufacturer for proper disposal being careful to properly label and securely package the material. Alternatively, the waste pharmaceutical shall be labeled, securely packaged and transported by a state licensed medical waste contractor to dispose by burial in a licensed hazardous or toxic waste landfill or incinerator.

As a general rule, when handling USP Reference Standards, avoid all contact and inhalation of dust, mists, and/or vapors associated with the material. Clean equipment and work surfaces with suitable detergent or solvent after use. After removing gloves, wash hands and other exposed skin thoroughly.

As with all dry powders, it is advisable to ground mechanical equipment in contact with dry material to dissipate the potential buildup of static electricity.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

Respiratory Protection: Where respirators are deemed necessary to reduce or control occupational exposures, use NIOSH-approved respiratory protection and have an effective respirator program in place. Gloves: Chemically compatible. For handling solutions, ensure that the glove material is protective against the solvent being used. Use handling practices that minimize direct hand contact. Employees who are sensitive to natural rubber (latex) should use nitrile or other synthetic nonlatex gloves. Use of powdered latex gloves should be avoided due to the risk of latex allergy. Eye Protection: Safety glasses with sideshields are recommended. Face shields or goggles may be required if splash potential exists or if corrosive materials are present. Approved eye protection (e.g., bearing the ANSI Z87 or CSA stamp) is preferred. Maintain eyewash facilities in the work area. Protective clothing: For handling of laboratory scale quantities, a cloth lab coat is recommended. Where significant quantities are handled, work clothing may be necessary to prevent take-home contamination.

Airborne exposure should be controlled primarily by engineering controls such as general dilution ventilation, local exhaust ventilation, or process enclosure. Local exhaust ventilation is generally preferred to general exhaust because it can control the contaminant at its source, preventing dispersion into the work area. An industrial hygiene survey involving air monitoring may be used to determine the effectiveness of engineering controls. Effectiveness of engineering controls intended for use with highly potent materials should be assessed by use of nontoxic surrogate materials. Local exhaust ventilation such as a laboratory fume hood or other vented enclosure is recommended, particularly for grinding, crushing, weighing, or other dust-generating procedures.

The manufacturer of darifenacin states that darifenacin dosage should not exceed 7.5 mg daily in patients receiving the drug concomitantly with potent CYP3A4 inhibitors, including clarithromycin.

Concomitant administration of clarithromycin and cisapride is contraindicated. Coadministration of clarithromycin and/or erythromycin with cisapride has been associated with QT prolongation and serious cardiac arrhythmias (ventricular tachycardia, ventricular fibrillation, torsades de pointes); fatalities have been reported. In 2 patients with chronic renal failure who were receiving cisapride (10 mg 3-4 times daily), QT prolongation and/or torsades de pointes occurred within several days after initiating therapy with clarithromycin (500 mg twice daily). Elevated serum cisapride concentrations observed in one patient decreased following discontinuance of clarithromycin.

Clarithromycin should be used with caution in patients receiving carbamazepine; if such concomitant therapy is used, a reduction in carbamazepine dosage and/or monitoring of plasma carbamazepine concentrations is advised. Limited data in healthy men indicate that clarithromycin may increase area under the serum concentration-time curve (AUC) for carbamazepine and decrease peak serum concentration and AUC for carbamazepine 10,11-epoxide (CBZ-E).2 51 In addition, increased plasma concentrations of carbamazepine (but not CBZ-E) and, in some patients, manifestations of carbamazepine toxicity (i.e., drowsiness, dizziness, ataxia) occurred within 3-5 days after initiation of clarithromycin therapy (200 mg twice daily) in several patients receiving carbamazepine (600 mg/day) with or without other drugs; plasma carbamazepine concentrations decreased and toxic manifestations subsided within several days following carbamazepine discontinuation.

The manufacturer of eszopiclone states that eszopiclone dosage should be reduced if the drug is used concomitantly with a potent CYP3A4 inhibitor, including clarithromycin. In such situations, the initial eszopiclone dosage should not exceed 1 mg but may be increased to 2 mg if clinically indicated.457

For more Interactions (Complete) data for Clarithromycin (36 total), please visit the HSDB record page.

Clarithromycin, like other macrolide antibiotics, has been linked to a low rate of acute, transient and usually asymptomatic elevations in serum aminotransferase levels which occur in 1% to 2% of patients treated for short periods and a somewhat higher proportion of patients given clarithromycin long term. Asymptomatic elevations in serum enzymes are particularly common among elderly patients given higher doses of clarithromycin.

EC50; Species: Ceriodaphnia dubia (Water Flea) age <24 hr; Conditions: freshwater, static, 25 °C; Concentration: 18660 ug/L for 24 hr (95% confidence interval: 15990-21770 ug/L); Effect: intoxication, immobilization />99% purity formulation/

EC50; Species: Ceriodaphnia dubia (Water Flea) age <24 hr; Conditions: freshwater, renewal, 25 °C, dissolved oxygen >90% saturated; Concentration: 8160 ug/L for 48 hr (95% confidence interval: 2700-18520 ug/L); Effect: decreased population abundance />99% purity formulation/

EC50; Species: Pseudokirchneriella subcapitata (Green Algae) exponential growth phase (Log) 1000 cells/mL; Conditions: freshwater, static, 25 °C, dissolved oxygen >90% saturated; Concentration: 2 ug/L for 3 days (95% confidence interval: 1.9-2.8 ug/L); Effect: decreased population abundance />99% purity formulation/

EC50; Species: Daphnia magna (Water Flea) age <24 hr neonate; Conditions: freshwater, static, 20 °C; Concentration: 25720 ug/L for 24 hr (95% confidence interval: 21720-30450 ug/L); Effect: intoxication, immobilization />99% purity formulation/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 150(SRC), determined from a log Kow of 3.16(2) and a regression-derived equation(3), indicates that clarithromycin is expected to have moderate mobility in soil(SRC). The pKa of clarithromycin is 8.99(2), indicating that this compound will exist almost entirely in the cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Volatilization from moist soil is not expected because the compound exists as an cation and cations do not volatilize. Clarithromycin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.3X10-25 mm Hg at 25 °C(SRC), determined from a fragment constant method(5). Utilizing the Closed Bottle test, 0% of the Theoretical BOD was reached in 4 weeks(6) indicating that biodegradation is not an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 150(SRC), determined from a log Kow of 3.16(2) and a regression-derived equation(3), indicates that clarithromycin is expected to adsorb to suspended solids and sediment(SRC). A pKa of 8.99(2) indicates clarithromycin will exist almost entirely in the cation form at pH values of 5 to 9 and therefore volatilization from water surfaces is not expected to be an important fate process(SRC). According to a classification scheme(4), an estimated BCF of 56(SRC), from its log Kow(2) and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Utilizing the Closed Bottle test, 0% of the Theoretical BOD was reached in 4 weeks(5) indicating that biodegradation is not an important environmental fate process in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), clarithromycin, which has an estimated vapor pressure of 2.3X10-25 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase clarithromycin may be removed from the air by wet or dry deposition(SRC). Clarithromycin has a reported UV max of 288 nm in methanol(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

/AQUATIC SPECIES/ The growth-inhibiting and binary joint effects of 12 antibacterial agents on the freshwater green alga Pseudokirchneriella subcapitata (Korschikov) Hindak were investigated over 72-hr exposures. The toxicity values (the median inhibitory concentration value, in micromoles) in decreasing order of sensitivity were triclosan (0.0018) > triclocarban (0.054) > roxithromycin (0.056) > clarithromycin (0.062) > tylosin (0.20) > tetracycline (2.25) > chlortetracycline (3.49) > norfloxacin (5.64) > sulfamethoxazole (7.50) > ciprofloxacin (20.22) > sulfamethazine (31.26) > trimethoprim (137.78). Several of these antibacterial compounds would be toxic at the micrograms per liter concentrations reported in surface waters and sewage effluents. Simple additive effects were observed in binary mixtures of sulfonamides, and most tylosin, triclosan, or triclocarban combinations. Potentially synergistic effects were observed in binary mixtures of the same class, such as macrolides, tetracyclines, and fluoroquinolones, as well as in some combined drugs, such as trimethoprim and sulfonamides or tylosin and tetracyclines. Potentially antagonistic effects were only observed between tylosin and triclocarban, triclosan and norfloxacin, and triclocarban and norfloxacin. Although present at low concentrations in the aquatic environment, mixtures of these antibacterial agents can potentially affect algal growth in freshwater systems due to their combined action.

/AQUATIC SPECIES/ Recent evidence indicates that a variety of antibiotic residues may affect the integrity of streams located downstream from wastewater treatment plants. Aquatic communities comprising bacterial and fungal decomposers and invertebrate detritivores (shredders) play an important role in the decomposition of allochthonous leaf litter, which acts as a primary energy source for small running waters. The aim of the present study was to assess whether an antibiotic mixture consisting of sulfamethoxazole, trimethoprim, erythromycin-H2O, roxithromycin, and clarithromycin has an effect on such a decomposer-detritivore system. Leaf discs were exposed to these antibiotics (total concentration of 2 or 200 ug/L) for approximately 20 days before offering these discs and corresponding control discs to an amphipod shredder, Gammarus fossarum, in a food choice experiment. Gammarus preferred the leaf discs conditioned in the presence of the antibiotic mixture at 200 ug/L over the control discs (pair-wise t test; p = 0.006). A similar tendency, while not significant, was observed for leaves conditioned with antibiotics at a concentration of 2 ug/L. The number of bacteria associated with leaves did not differ between treatments at either antibiotic concentration (t test; p = 0.57). In contrast, fungal biomass (measured as ergosterol) was significantly higher in the 200 ug/L treatment (t test; p = 0.038), suggesting that the preference of Gammarus may be related to a shift in fungal communities. Overall these results indicate that mixtures of antibiotics may disrupt important ecosystem processes such as organic matter flow in stream ecosystems, although effects are likely to be weak at antibiotic concentrations typical of streams receiving wastewater treatment plant effluents.

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from, as of June 21, 2012: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=81103-11-9]

Clarithromycin exhibited a median concentration of 0.87 ug/L (0.536 ug/L maximum) in 8 wastewater treatment plant final effluents sampled in five Canadian cities during 2002; detection limit = 0.001 ug/L(1). Clarithromycin was detected in one of 5 influent samples at a concentration of 112 ng/L (Feb 9, 2007) (limit of detection was 1 ng/L); it was not detected in effluent samples. Sampling took place at a wastewater treatment plant in Kentucky serving a local community of approximately 15,000 with an additional influx of approximately 10,000 students, academic year 2006-2007(2). Median concentrations of clarithromycin were 380 ng/L in raw influents and 240 ng/L in tertiary effluents of conventional wastewater treatment employed in Zurich, Switzerland(3). Clarithromycin concentration ranges in treated effluents of 3 wastewater treatment plants (Zurich-Werdhoelzli, Kloten-Opfikon, and Duebendorf, Switzerland) were 194-328, 97-163, and 57-135 ng/L, respectively; sampling was conducted in July 2000(4). The influent and effluent load ranges of not detected to 46 and not detected to 421 mg/day/100 inhabitants, respectively, was reported in the analysis of 6 sewage treatment plants located in Italy (Cagliari, Naples, Latina, Cuneo, Varese Olona, Varese Lago); median concentrations were 21 and 55 mg/day/100 inhabitants, respectively(5). The compound was reported in effluents from 9 Italian sewage treatment plants at a median concentration of 18.1 ng/L(6). Clarithromycin exhibited percent frequencies of detection of 77, 85, and 83 in waste water influent, effluent, and sewage sludge, respectively, based on analysis of 3 wastewater treatment plants in Catalonia, Spain during 8 sampling campaigns. Limits of detection were 5.0 ng/L, 4.0 ng/L and 7.1 ng/g in influent, effluent and sludge, respectively(7). Clarithromycin concentrations in sewage water effluents of the Netherlands in 2002 ranged from approximately 120 to 550 ng/L(8).

The Koc of clarithromycin is estimated as 150(SRC), using a log Kow of 3.16(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that clarithromycin is expected to have moderate mobility in soil. The pKa of clarithromycin is 8.99(1), indicating that this compound will exist almost entirely in the cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4).

Using a 2.4 meter soil column, treated effluent was applied to the top of the column over 23 days, simulating a recharge condition similar to those in arid or semiarid climates. The soil used was a Mohall-Laveen sandy loam from an area northwest of Phoenix, AZ with no known history of cultivation or irrigation. Secondarily treated effluent from a 17.5 million gallon/day municipal waste water treatment plant serving 120,000-150,000 residents near Phoenix, AZ was employed. Clarithromycin was not detected in the outflow of the column; reporting limit not determined(1). Clarithromycin was shown to absorb to suspended solids and sludge during waste water treatment plant processes; Kd values in activated sludge were 300 and 400 for October 2003 and February 2004, respectively, at municipal treatment facilities in Switzerland (a KD of 262 was reported for an unspecified field study)(2). Percentage of attenuation in surface water particulates was reported as 41% in a study of the River Olona which receives effluent from the Varese Olona Sewage Treatment Plant, Italy(3).

/CASE REPORTS/ Myelotoxicity, a major toxicity of vinorelbine. may be related to the degree of one's exposure to vinorelbine. In theory, clarithromycin has the potential to alter vinorelbine's pharmacokinetics by inhibiting CYP3A and/or P-glycoprotein; this may result in massive exposure to vinorelbine and severe toxicity. ... A total of 12 (63.2%) and 11 (27.5%) episodes of grade 3/4 neutropenia occurred among the patients who were and were not administered clarithromycin, respectively. The incidence of grade 4 neutropenia was higher in the group administered clarithromycin than in those who did not receive it (31.6% vs 2.5%; p = 0.0033). Vinorelbine dose, concomitant clarithromycin administration, and female sex were significantly correlated with severe neutropenia, with unadjusted odds ratios of 0.07 (95% CI 0.01 to 0.59), 4.52 (95% CI 1.41 to 14.45), and 4.55 (95% CI 1.39 to 14.29), respectively. Compared with patients who are administered vinorelbine alone, patients who are administered clarithromycin during chemotherapy with vinorelbine are at a higher risk for severe neutropenia. Physicians should educate their patients about this interaction. If possible, clarithromycin administration should be avoided in patients who will undergo chemotherapy with vinorelbine in the near future. However, further prospective pharmacokinetic studies are required to confirm this interaction.

/CASE REPORTS/ The case is presented of a 70-yr-old woman who developed prolonged QT syndrome following treatment with 250 mg oral clarithromycin twice daily for 4 days. Concomitant therapy included sotalol, nitroglycerin, prednisone, hydroxychloroquine, and methotrexate. Before beginning clarithromycin, the patient had a QTc of 440/498 msec. After 4 days of clarithromycin therapy, the QT/QTc was 696/641 msec. Clarithromycin and sotalol were discontinued. Over the next 5 days, QT/QTc returned to normal values, resting heart rate increased, and the patient had no syncopal or ischemic pain episodes. She was discharged on her previous medications with the exception of clarithromycin and sotalol. The suggestion that clarithromycin contributed to QT prolongation was supported by a lack of symptoms during 3 months of sotalol therapy before initiation of clarithromycin, rapid prolongation of the QT after clarithromycin initiation, and reversal upon stopping clarithromycin and sotalol

/CASE REPORTS/ A case of an acute toxic cholestatic reaction to clarithromycin, proven by liver biopsy, in a patient with comorbid diseases, prior exposure to erythromycin and ultimate death /is reported/. No autopsy was performed. A 59-year-old woman with diabetes mellitus and chronic renal insufficiency received clarithromycin 500 mg twice daily for 3 days for acute maxillary sinusitis and then developed a rash and jaundice. She was hospitalized 11 days after stopping clarithromycin. Progressive cholestatic jaundice accompanied by oligo-anuric renal failure requiring hemodialysis ensued. Liver biopsy showed pure bilirubinostasis without parenchymal inflammation. On the 22nd hospital day, after clinical deterioration, she died from an apparent cardiopulmonary death. ...

/CASE REPORTS/ Clarithromycin is a macrolide antibiotic structurally related to erythromycin. Although ototoxicity has been reported with erythromycin, few reports have documented clarithromycin induced hearing loss (most affected patients received 2000 mg/day). This case report describes ototoxicity in a patient receiving clarithromycin 500 mg/day. The patient was an 80 year old, 27 kg, female with chronic renal insufficiency. Liver enzymes (AST, ALT) were normal. The patient experienced severe hearing loss while receiving a 24 day course of clarithromycin for a Mycobacterium avium respiratory infection. The dose of clarithromycin was adjusted for body weight and decreased renal function. Hearing loss was observed clinically, but unconfirmed by audiometric testing. Confounding factors may have contributed, but clarithromycin was thought to be the cause.

/GENOTOXICITY/ In the in vitro chromosome aberration test, clarithromycin produced weakly positive results in one test and negative results in another.

AEROBIC: Clarithromycin, present at 2.43 mg/L, reached -3 and 0% of its theoretical BOD in 14 and 28 days, respectively, using a sewage inoculum at 2 drops/L in the Closed Bottle test(1). Clarithromycin was not removed in sewage treatment plants equipped with pretreatment, primary settling and activated sludge processes(2). In a mass balance assessment study, 1% persisted in sludge, 79% is released in effluents, and 20% is lost to degradation or otherwise unaccounted for during sewage treatment(3). Clarithromycin present at 3000 ng/g biosolid and stored under aerobic conditions exhibited a degradation rate constant of 0.596/day, 50% dissipation time of 1.2 days(4).

The Approved Drug Products with Therapeutic Equivalence Evaluations identifies currently marketed prescription drug products, including clarithromycin, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

J01FA09

J01FA09

J - Antiinfectives for systemic use

QJ - Antiinfectives for systemic use

J01FA09

Clarithromycin is a macrolide antibiotic whose spectrum of activity includes many gram-positive (<i>Staphylococcus aureus, S. pneumoniae, and S. pyogenes</i>) and gram-negative aerobic bacteria (<i>Haemophilus influenzae, H. parainfluenzae, and Moraxella catarrhalis</i>), many anaerobic bacteria, some mycobacteria, and some other organisms including <i>Mycoplasma, Ureaplasma, Chlamydia, Toxoplasma</i>, and <i>Borrelia</i>. Other aerobic bacteria that clarithromycin has activity against include <i>C. pneumoniae and M. pneumoniae</i>. Clarithromycin has an in-vitro activity that is similar or greater than that of erythromycin against erythromycin-susceptible organisms. Clarithromycin is usually bacteriostatic, but may be bactericidal depending on the organism and the drug concentration.

Clarithromycin is first metabolized to 14-OH clarithromycin, which is active and works synergistically with its parent compound. Like other macrolides, it then penetrates bacteria cell wall and reversibly binds to domain V of the 23S ribosomal RNA of the 50S subunit of the bacterial ribosome, blocking translocation of aminoacyl transfer-RNA and polypeptide synthesis. Clarithromycin also inhibits the hepatic microsomal CYP3A4 isoenzyme and P-glycoprotein, an energy-dependent drug efflux pump.

Clarithromycin usually is bacteriostatic, although it may be bactericidal in high concentrations or against highly susceptible organisms. Bactericidal activity has been observed against Streptococcus pyogenes, S. pneumoniae, Haemophilus influenzae, and Chlamydia trachomatis. Clarithromycin inhibits protein synthesis in susceptible organisms by penetrating the cell wall and binding to 50S ribosomal subunits, thereby inhibiting translocation of aminoacyl transfer-RNA and inhibiting polypeptide synthesis. The site of action of clarithromycin appears to be the same as that of erythromycin, clindamycin, lincomycin, and chloramphenicol.

3-4 hours

Following oral administration of single 250-mg or 1.2-g doses of clarithromycin conventional tablets in healthy men, the elimination half-life averaged 4 or 11 hours, respectively. During multiple dosing every 12 hours, the elimination half-life of clarithromycin reportedly increased from 3-4 hours following a 250-mg dose (conventional tablets) every 12 hours to 5-7 hours following a 500-mg dose every 8-12 hours; the half-life of 14-hydroxyclarithromycin increased from 5-6 hours with a 250-mg dose to 7-9 hours with a 500-mg dose. When clarithromycin is administered as the oral suspension, the elimination half-life of the drug and of its 14-hydroxy metabolite appear to be similar to those observed at steady-state following administration of equivalent doses of clarithromycin as tablets.

Hepatic - predominantly metabolized by CYP3A4 resulting in numerous drug interactions.

The principal metabolite found in urine is 14-hydroxyclarithromycin, which accounts for approximately 10-15% of the dose following administration of 250 or 500 mg of clarithromycin as tablets.

Clarithromycin is extensively metabolized in the liver, principally by oxidative N- demethylation and hydroxylation at the 14 position; hydrolytic cleavage of the cladinose sugar moiety also occurs in the stomach to a minor extent. Although at least 7 metabolites of clarithromycin have been identified, 14-hydroxyclarithromycin is the principal metabolite in serum and the only one with substantial antibacterial activity. While both the R- and S-epimers of 14-hydroxyclarithromycin are formed in vivo, the R-epimer is present in greater amounts and has the greatest antimicrobial activity. Metabolism of clarithromycin appears to be saturable since the amount of 14-hydroxyclarithromycin after an 800-mg dose of the parent drug is only marginally greater than that after a 250-mg dose.

Following oral administration of a single 250-mg dose of radiolabeled clarithromycin in healthy men, approximately 38% of the dose (18% as clarithromycin) was excreted in urine, and 40% in feces (4% as clarithromycin), over 5 days. ... The principal metabolite found in urine is 14-hydroxyclarithromycin, which accounts for approximately 10-15% of the dose following administration of 250 or 500 mg of clarithromycin as tablets.

H1250JIK0A

CLARITHROMYCIN

Established Pharmacologic Class [EPC] - Macrolide Antimicrobial

Chemical Structure [CS] - Macrolides

Mechanisms of Action [MoA] - Cytochrome P450 3A4 Inhibitors

Mechanisms of Action [MoA] - Cytochrome P450 3A Inhibitors

Compounds which inhibit the synthesis of proteins. They are usually ANTI-BACTERIAL AGENTS or toxins. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins.

Substances that inhibit the growth or reproduction of BACTERIA.

Drugs and compounds which inhibit or antagonize the biosynthesis or actions of CYTOCHROME P-450 CYP3A.

Clarithromycin is well-absorbed, acid stable and may be taken with food.

After a 250 mg tablet every 12 hours, approximately 20% of the dose is excreted in the urine as clarithromycin, while after a 500 mg tablet every 12 hours, the urinary excretion of clarithromycin is somewhat greater, approximately 30%.

Limited data are available on the distribution of clarithromycin in humans. Clarithromycin and 14-hydroxyclarithromycin appear to be distributed into most body tissues and fluids. Because of high intracellular concentrations of the drug, tissue concentrations are higher than serum concentrations. High concentrations of clarithromycin were present in tissue samples obtained from patients undergoing surgery. In patients who received 250-500 mg of clarithromycin orally every 12 hours for 3 days prior to surgery, peak clarithromycin concentrations in lung, tonsils, and nasal mucosa reportedly were attained 4 hours after administration and averaged 13.5-17.5, 5.3-6.5, and 5.9-8.3 mg/ kg, respectively; however, it has been suggested that these data may represent an overestimate of clarithromycin tissue concentrations because of the microbiologic assay's inability to distinguish between parent drug and its active metabolite. In children receiving clarithromycin suspension for otitis media at a dosage of 7.5 mg/kg every 12 hours for 5 doses, peak clarithromycin and 14- hydroxyclarithromycin concentrations in middle ear fluid were 2.5 and 1.3 ug/ mL, respectively; concomitant serum concentrations were 1.7 and 0.8 ug/mL, respectively. Results of studies in animals given radiolabeled clarithromycin or erythromycin indicate higher and more prolonged activity of clarithromycin in various body tissues, particularly the lung

Clarithromycin is absorbed rapidly from the GI tract after oral administration; GI absorption of the drug exceeds that of erythromycin.

Clarithromycin is eliminated by both renal and nonrenal mechanisms.

Following oral administration of a single 250-mg dose of radiolabeled clarithromycin in healthy men, approximately 38% of the dose (18% as clarithromycin) was excreted in urine, and 40% in feces (4% as clarithromycin), over 5 days. With oral administration of 250 or 500 mg of clarithromycin as tablets every 12 hours, approximately 20 or 30% of the respective dose is excreted unchanged in urine within 12 hours. After an oral clarithromycin dosage of 250 mg every 12 hours as the suspension, approximately 40% of the administered dose is excreted unchanged in urine. The principal metabolite found in urine is 14-hydroxyclarithromycin, which accounts for approximately 10-15% of the dose following administration of 250 or 500 mg of clarithromycin as tablets.

MEDICATION

Use (kg) in Switzerland (2009): >1000

Preparation: Y. Watanable, et al., EP 41355; eidem, US 4331803 (1981, 1982 both to Taisho)

Antibiotics are fermentation products and are isolated either as unfinished products or as intermediates, generally solid substances of limited stability. They are purified by methods normally employed in organic chemistry, which include chromatography, crystallization, and precipitation. /Antibiotics/

Table: Clarithromycin Preparations [Table#8043]

Table: Clarithromycin Combinations [Table#8044]

Trade Names: Clarosip /Grunenthal/; Clathromycin /Taisho/; Cyllind /Abbott/; Klacid /Abbott/; Klaricid /Abbott/; Macladin /Guidotti/; Naxy /Sanofi Winthrop/; Veclam /Zambon/; Zeclar /Abbott/.

Pharmaceuticals

Pharmaceuticals -> Antiinfectives for systemic use -> Antibacterials for systemic use -> Macrolides, lincosamines and streptogramins -> Macrolides -> Antibiotics