Clarithromycin

Indications

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 yr: 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 mth-12 yr: 7.5 mg/kg every 12 hr. 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 mth-12 yr: 7.5 mg/kg every 12 hr. 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 mth-12 yr: 7.5 mg/kg every 12 hr. Dose to be given via infusion into proximal vein.

CrCl (ml/min)	Dosage Recommendation
<30	Half the dosage or double dosing interval.

Contraindications

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

Warnings / Precautions

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

Adverse Reactions

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

Overdose Reactions

GI symptoms e.g. abdominal pain, vomiting, nausea and diarrhoea. Prompt elimination of unabsorbed drug and supportive treatment should be instituted. Haemodialysis or peritoneal dialysis not expected to be helpful.

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.
See Below for More clarithromycin Drug Interactions

Food Interactions

Food may interfere with absorption though not clinically significant.

Mechanism of Actions

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.
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 hr and 5-7 hr (elimination half-life)