Oral absorption of cimetidine and its clearance in patients with renal failure.

The plasma concentration curve after a single oral dose of cimetidine 200 mg was followed in 27 patients with varying degrees of chronic renal failure (creatinine clearance 1--52 ml/min) and in 46 patients with normal serum creatinine. Compared to the latter patients, the plasma concentration was higher and the elimination rate was slower in all uraemic subjects, including a group with moderate renal impairment. The preliminary recommendations of dosage for patients with a creatinine clearance below 5 ml/min, and for patients on regular haemodialysis, is cimetidine 200 mg every 12 h, 5-15 ml/min 200 mg every 12 to 8 h, 15-30 ml/min 200 mg every 8 h and 30-52 ml/min 200 mg every 6 h.