Adults

Standard adult dose is 250 mg to 500 mg every 8 hours, or 500 mg to 875 mg every 12 hours, depending on the severity and type of infection. For severe infections, doses may be increased. Max: 4 g/day.

Elderly

No specific dose adjustment is generally required for elderly patients with normal renal function. Dose adjustments may be necessary based on renal function.

Renal_impairment

Dose reduction is required for patients with severe renal impairment (CrCl < 30 mL/min). A common recommendation is 250 mg every 8-12 hours, depending on the severity.

Onset

Within 30-60 minutes.

Excretion

Primarily excreted unchanged in the urine via renal tubular secretion and glomerular filtration. About 60-80% of an oral dose is excreted in the urine within 6-8 hours.

Half life

Approximately 1-1.5 hours in adults with normal renal function.

Absorption

Rapidly and well absorbed from the gastrointestinal tract, with bioavailability of approximately 70-90%. Peak plasma concentrations are reached within 1-2 hours after oral administration.

Metabolism

Limited metabolism, mainly converted to inactive penicilloic acid.

Probenecid

Increases and prolongs plasma levels of amoxicillin by decreasing renal tubular secretion.

Allopurinol

Increased incidence of rash, particularly in patients with hyperuricemia.

Methotrexate

Increased methotrexate toxicity due to reduced renal excretion. Monitor methotrexate levels.

Oral Contraceptives

May reduce efficacy of oral contraceptives (rarely). Advise additional contraceptive methods.

Oral Anticoagulants (e.g., Warfarin)

Increased INR/bleeding risk. Monitor coagulation parameters.