Clarithromycin information from DrugsUpdate  

Pharmacodynamics

Pharmacokinetics

Clarithromycin inhibits protein synthesis by binding to 50s ribosomal subunits of susceptible organisms. It has activity against susceptible streptococci and staphylococci as well as other species including B. catarrhalis, L. spp, C. trachomatis and U. urealyticum.

Intravenous
Store at 15-25°C.

Absorption
Rapidly absorbed from the GI tract (oral).

Distribution
Widely distributed (concentrations exceed those in serum); enters the breast milk.

Metabolism
Hepatic (extensive); converted to 14-hydroxyclarithromycin and other metabolites.

Excretion
Via the bile into the faeces; via the urine (20-30% as unchanged, 10-15% as 14-hydroxyclarithromycin and other metabolites).3-4 hours and 5-7 hours (elimination half-life)

Clarithromycin Indications / Clarithromycin Uses

Information Not Available

Clarithromycin Adverse Reactions / Clarithromycin Side Effects

GI upset, glossitis, stomatitis, altered taste; headache, dizziness, hallucinations, insomnia, other CNS effects; rash; hepatic dysfunction, Potentially Fatal: Pseudomembranous colitis, anaphylaxis, Stevens-Johnson syndrome.

Precautions

Prescribing Clarithromycin extended-release tablets in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

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 dosage or prolonged dosing intervals may be appropriate.

Exacerbation of symptoms of myasthenia gravis and new onset of symptoms of myasthenic syndrome has been reported in patients receiving Clarithromycin therapy.

Special Precautions

Renal and hepatic impairment; macrolide cross-resistance; lactation, children.

Other Drug Interactions

May potentiate oral anticoagulant action. May elevate serum digoxin concentration.

Potentially Fatal: Increases plasma concentrations of terfenadine or astemizole. Increases the risk of ventricular arrhythmias in patients with preexisting cardiac diseases.

Other Interactions

Food Interactions
Food may interfere with absorption though not clinically significant.

Dosage

Oral
Susceptible infections
Adult: 250 mg bid increased to 500 mg bid for severe infections if necessary for 7-14 days.
Child: 7.5 mg/kg bid for 5-10 days.
CrCl (ml/min)   Dosage Recommendation
<30                 Half the dosage or double dosing interval.

Oral
Respiratory tract infections
Adult: 250 mg bid increased to 500 mg bid for severe infections if necessary for 7-14 days.
Child: 7.5 mg/kg bid for 5-10 days.
CrCl (ml/min)  Dosage Recommendation
<30                Half the dosage or double dosing interval.

Oral
Skin and soft tissue infections
Adult: 250 mg bid increased to 500 mg bid for severe infections if necessary for 7-14 days.
Child: 7.5 mg/kg bid for 5-10 days.
CrCl (ml/min)  Dosage Recommendation
<30                Half the dosage or double dosing interval.

Oral
Mycobacterium avium complex infections
Adult: 500 mg bid in combination with other antimycobacterials.
Child: 7.5 mg/kg bid; to be used with other antimycobacterials. May increase dose to 15 mg/kg (max: 500 mg) bid.
CrCl (ml/min) Dosage Recommendation
<30               Half the dosage or double dosing interval.

Oral
Leprosy
Adult: 500 mg daily as part of an alternative multidrug therapy.
CrCl (ml/min) Dosage Recommendation
<30               Half the dosage or double dosing interval.

Oral
Eradication of H. pylori associated with peptic ulcer disease
Adult: 500 mg bid; given in combination with another antibacterial and either a proton pump inhibitor or H2-receptor antagonist for 7-14 days.
Child: ≥1 year: 7.5 mg/kg bid; may be given with another antibacterial and a proton pump inhibitor for 7 days.
CrCl (ml/min) Dosage Recommendation
<30               Half the dosage or double dosing interval.

Intravenous
Respiratory tract infections
Adult: 500 mg bid for 2-5 days. Dose to be infused over 60 minutes in a 0.2% solution; revert to oral therapy whenever possible.
Child: 1 month–12 years: 7.5 mg/kg every 12 hours. Dose to be given via infusion into proximal vein.
CrCl (ml/min)   Dosage Recommendation
<30                 Half the dosage or double dosing interval.

Intravenous
Skin and soft tissue infections
Adult: 500 mg bid for 2-5 days. Dose to be infused over 60 minutes in a 0.2% solution; revert to oral therapy whenever possible.
Child: 1 month–12 year: 7.5 mg/kg every 12 hours. Dose to be given via infusion into proximal vein.
CrCl (ml/min) Dosage Recommendation
<30 Half the dosage or double dosing interval.

Intravenous
Susceptible infections
Adult: 500 mg bid for 2-5 days. Dose to be infused over 60 minutes in a 0.2% solution; revert to oral therapy whenever possible.
Child: 1 month–12 years: 7.5 mg/kg every 12 hour. Dose to be given via infusion into proximal vein.
CrCl (ml/min) Dosage Recommendation
<30 Half the dosage or double dosing interval.

Food(before/after)

Standard release tab
May be taken with or without food.

Oral susp
May be taken with or without food.

XL & MR tab
Should be taken with food. (Swallow whole, do not chew/crush.)

Clarithromycin and Pregnancy

Contraindicated in pregnancy.

Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Clarithromycin and Lactation

Caution when used during lactation.

Clarithromycin and Children

Safety and effectiveness of Clarithromycin in pediatric patients under 6 months of age have not been established. The safety of Clarithromycin has not been studied in MAC patients under the age of 20 months. Neonatal and juvenile animals tolerated Clarithromycin in a manner similar to adult animals. Young animals were slightly more intolerant to acute overdosage and to subtle reductions in erythrocytes, platelets, and leukocytes but were less sensitive to toxicity in the liver, kidney, thymus, and genitalia.

Clarithromycin and Geriatic

In a steady-state study in which healthy elderly subjects (age 65 to 81 years old) were given 500 mg every 12 hours, the maximum serum concentrations and area under the curves of Clarithromycin and 14-OH Clarithromycin were increased compared to those achieved in healthy young adults. These changes in pharmacokinetics parallel known age-related decreases in renal function. In clinical trials, elderly patients did not have an increased incidence of adverse events when compared to younger patients. Dosage adjustment should be considered in elderly patients with severe renal impairment.

Clarithromycin and Other Contraindications

Hypersensitivity. Patients receiving terfenadine, astemizole, pimozide, cisapride and ergot derivatives. Pregnancy; history of acute porphyria.

Storage

Intravenous
Store at 15-25°C.

Lab interference

Intravenous
Store at 15-25°C.