Citalopram pharmacokinetics in patients with chronic renal failure and theeffect of haemodialysis

Objective: To study the effects of severe renal failure and haemodialysis o n the pharmacokinetics of citalopram. Methods: Four patients with renal failure undergoing haemodialysis and eigh t healthy controls were given a single dose of citalopram. The concentratio ns of citalopram and its metabolites desmethylcitalopram and didesmethylcit alopram were measured in serum and urine. On a different day, the four pati ents undergoing haemodialysis were given another single dose of citalopram, and the drug concentrations were measured in serum from the artery leading to the dialyser and in the dialysate. In addition, one anuric patient trea ted with citalopram on a regular basis was included in the study. Results. There were no significant differences between the two groups in an y of the pharmacokinetic parameters with the exception of the renal clearan ce of citalopram, which was significantly lower in the renal failure group than in the control group (1.70 ml/min versus 66.2 ml/min, P < 0.001). Oral clearance of citalopram was almost identical in the two groups (452 ml/min versus 456 ml/min). The process of haemodialysis cleared about 1% of the d ose as citalopram and 1% as desmethylcitalopram only. Conclusion: Severe renal failure does not affect the pharmacokinetics of ci talopram and modification of the usual citalopram dose does thus not seem t o be necessary. The contribution of haemodialysis to the total elimination of citalopram is negligible.