Adults

For C. difficile-associated diarrhea: 125 mg to 500 mg orally 3 to 4 times daily for 10 to 14 days, depending on severity. For enterocolitis: 500 mg orally 3 to 4 times daily.

Elderly

No specific dose adjustment for elderly patients based on age alone, but consideration for renal function and overall health status is important, especially for those with severe gastrointestinal inflammation that could lead to increased systemic absorption.

Renal_impairment

Since oral vancomycin is minimally absorbed systemically, renal impairment generally does not necessitate dosage adjustment for the treatment of CDAD or enterocolitis. However, if there is significant inflammation in the gut leading to increased absorption, monitor for systemic toxicity.

Onset

Local therapeutic effect on C. difficile within hours.

Excretion

Mainly excreted unchanged in feces (for oral administration); systemic excretion is primarily renal (glomerular filtration) for absorbed drug.

Half life

Approximately 4-6 hours in adults with normal renal function (systemic absorption is minimal for oral use).

Absorption

Poorly absorbed from the gastrointestinal tract (less than 10% systemically) when administered orally; primarily acts locally in the gut.

Metabolism

Minimally metabolized; negligible metabolism for oral administration.

Cholestyramine, Colestipol

May bind vancomycin in the gut, potentially reducing its local efficacy. Administer vancomycin several hours before or after these agents.

Other Ototoxic/Nephrotoxic Drugs (e.g., Aminoglycosides, Amphotericin B, Cisplatin, Cyclosporine)

While systemic absorption of oral vancomycin is minimal, theoretical risk of additive toxicity if significant absorption occurs (e.g., in severe inflammatory bowel disease).