Adults

Typical dose is 250 mg to 500 mg twice daily for 7-14 days, depending on the infection. For H. pylori eradication, usually 500 mg twice daily as part of a triple therapy regimen.

Elderly

No specific dose adjustment is usually required in elderly patients with normal renal function. Monitor renal function.

Renal_impairment

For patients with severe renal impairment (creatinine clearance <30 mL/min), the dose should be halved or dosing frequency reduced (e.g., 250 mg once daily or 500 mg once daily for H. pylori, or prolonging intervals).

Onset

Peak plasma concentrations are achieved within 2-3 hours.

Excretion

Approximately 20-40% of the dose is excreted unchanged in the urine, and about 10-15% as the 14-hydroxy metabolite. The remainder is excreted via bile and feces.

Half life

The elimination half-life is typically 3-7 hours for the 500 mg dose.

Absorption

Well absorbed from the gastrointestinal tract; bioavailability is about 50-55%. Food may delay but does not affect the extent of absorption.

Metabolism

Extensively metabolized in the liver, primarily by the CYP3A4 enzyme, to its active metabolite 14-hydroxyclarithromycin.

Digoxin

Increased serum digoxin levels. Monitor digoxin levels.

Warfarin

Potentiates anticoagulant effect, leading to increased INR and bleeding risk. Monitor INR closely.

Colchicine

Increased exposure to colchicine, especially in renal/hepatic impaired patients, leading to severe side effects. Avoid co-administration.

CYP3A4 Inducers/Inhibitors

Substrate and inhibitor of CYP3A4, leading to altered levels of co-administered drugs.

Oral Hypoglycemics/Insulin

Can potentiate hypoglycemic effects. Monitor blood glucose.

Statins (Simvastatin, Lovastatin)

Increased risk of myopathy/rhabdomyolysis. Avoid co-administration. If necessary, use alternative statins or reduce statin dose and monitor carefully.