Adults

The usual adult dose for most infections is 1 to 2 grams daily, given as a single dose or in two divided doses. For Strep throat, 1 g daily as a single dose or 500 mg twice daily for 10 days.

Elderly

Dosage should be adjusted based on renal function due to potential age-related decline in kidney function. Monitor creatinine clearance.

Renal_impairment

Initial dose is 1 gram, then maintenance doses should be adjusted based on creatinine clearance: CrCl 25-50 ml/min: 500 mg every 12 hours; CrCl 10-24 ml/min: 500 mg every 24 hours; CrCl <10 ml/min: 500 mg every 36 hours. Patients on hemodialysis should receive an additional dose after dialysis.

Onset

Rapid onset of action, typically within 1-2 hours following oral administration.

Excretion

Primarily excreted unchanged in the urine by glomerular filtration and tubular secretion. Approximately 90% of the dose is excreted within 24 hours.

Half life

Approximately 1.5 to 2 hours in individuals with normal renal function. It is significantly prolonged in patients with impaired renal function.

Absorption

Well absorbed from the gastrointestinal tract (approximately 90%) after oral administration. Peak plasma concentrations are reached within 1-2 hours.

Metabolism

Cefadroxil is not extensively metabolized in the body. Approximately 20% is protein bound.

Probenecid

Concurrent administration of probenecid decreases the renal tubular secretion of cefadroxil, resulting in increased and prolonged plasma concentrations of cefadroxil.

Aminoglycosides

Although uncommon, concurrent use with aminoglycosides may potentially increase the risk of nephrotoxicity.

Oral Contraceptives

Antibiotics may decrease the effectiveness of oral contraceptives. Advise patients to use an alternative or additional method of contraception while on antibiotics.

Anticoagulants (e.g., Warfarin)

Cephalosporins, including cefadroxil, may infrequently alter vitamin K metabolism, potentially increasing the anticoagulant effect of warfarin. Monitor INR/PT.