The new H1-receptor antagonist,
cetirizine, is eliminated primarily unchanged by renal excretion and is thus potentially useful for relief of
pruritus in patients with hepatic dysfunction, in whom many H1-receptor antagonists are contraindicated. The authors studied the elimination of
cetirizine in six patients with
primary biliary cirrhosis. In contrast to data obtained in healthy adults with normal hepatic function reported in the medical literature, they found that the mean serum elimination half-life value of
cetirizine, 13.8 +/- 1.8 hours, was longer, and the mean clearance rate, 0.44 +/- 0.10 mL/min/kg, was lower (P < .05). The mean peak serum
cetirizine concentration, 498 +/- 118 ng/mL, was higher, the mean area under the curve, 6438 +/- 1621 ng/mL/hr, was larger, and the mean fraction of the dose excreted as unchanged
cetirizine in the urine, .32 +/- .14, was lower (P < .05). The duration of action of
cetirizine was prolonged, as evidenced by significant suppression of the
histamine-induced wheal and flare for 48 and 72 hours, respectively, after a single dose.
Cetirizine elimination was impaired in patients with hepatic dysfunction.