Pharmacokinetics of orally administered levocabastine in patients with renal insufficiency

Drug metabolism and pharmacokinetics

In this article, aspects of absorption, distribution, metabolism, and excretion have been described bearing in mind the pathogenesis of allergic diseases and their possible therapeutic opportunities. The importance of the routes of administration of the different therapeutic groups has been emphasized. The classical aspects of drug metabolism and disposition related to oral administration have been reviewed, but special emphasis has been given to intranasal, cutaneous, transdermal, and ocular administration as well as to the absorption and the subsequent bioavailability of drugs. Drug-metabolizing enzymes and transporters present in extrahepatic tissues, such as nasal mucosa and the respiratory tract, have been particularly discussed. As marketed antiallergic drugs include both racemates and enantiomers, aspects of stereoselective absorption, distribution, metabolism, and excretion have been discussed. Finally, a new and promising methodology, microdosing, has been presented, although it has not yet been applied to drugs used in the treatment of allergic diseases.

The pharmacokinetics of pioglitazone in patients with impaired renal function

AIMS

To evaluate the effect of renal impairment on the pharmacokinetics and safety of pioglitazone and its metabolites M-III and M-IV with impaired renal function and normal renal function.

METHODS

In a phase-I, open-label, parallel-group study, six healthy subjects with normal renal function (creatinine clearance> 80 ml min-1), nine patients with moderate renal impairment (creatinine clearance 30-60 ml min-1) and 12 patients with severe renal impairment (creatinine clearance < 30 ml min-1) received single and multiple oral doses of pioglitazone 45 mg. The serum pharmacokinetic profiles of pioglitazone and its metabolites M-III and M-IV were assessed for the first and last dose administered (day 1 and day 12, respectively).

RESULTS

Pharmacokinetic data revealed no significant accumulation of pioglitazone or its metabolites M-III and M-IV in patients with renal impairment. There was no significant difference in the pharmacokinetic profile of pioglitazone in subjects with normal and with moderately impaired renal function. After single oral doses, mean area under the concentration-time curve (AUC) values were decreased in patients with severe renal impairment compared with healthy subjects with normal renal function for pioglitazone (13 476 vs 17 387, P = 0.371; -23%; confidence interval (CI) -57, 38), M-III metabolite (13 394 vs 15 071, P = 0.841; -11%; CI -74, 194) and M-IV metabolite (27 991 vs 49 856, P = 0.006; -44%; CI -62, -17). After repeated oral doses of pioglitazone, mean AUC values (microg.h l-1) were decreased in patients with severe renal impairment compared with healthy subjects with normal renal function for pioglitazone (8744 vs 14,565, P = 0.004; -40%; CI -57, -16), M-III (3991 vs 7,289, P = 0.0009; -45%; CI -60, -25) and M-IV (21 080 vs 25 706, P = 0.181; -18%; CI 39, 10). The tolerability and safety profile of pioglitazone was comparable between groups.

CONCLUSIONS

Pioglitazone was well tolerated in patients with varying degrees of renal impairment. Although mean serum concentrations of pioglitazone and its metabolites are increased in patients with severe renal impairment, adjustment of starting and maintenance doses in these patients is probably unwarranted.

[Pharmacological and clinical properties of levocabastine hydrochloride (eye drop and nasal spray), a selective H1 antagonist]

Levocabastine is a selective histamine H1-receptor antagonist exerting inhibitory effects on the release of chemical mediators from mast cells and on the chemotaxis of polymorphonuclear leukocytes and eosinophils. Both histamine and antigens induced conjunctivitis was inhibited by levocabastine in several allergy models. Levocabastine moderately inhibited histamine-release from guinea pig conjunctive induced by antigen-antibody reactions and prevented an increase in the vascular permeability of the conjunctive elicited by both histamine and antigen instillation. Symptoms of allergic rhinitis, which were induced by histamine, substance P and antigen, were also reduced by levocabastine. Levocabastine prevented an increase in the vascular permeability of nasal mucosa elicited by instillation of these three inducers. Furthermore, levocabastine has shown a large difference between the antiallergic dose and other non-specific pharmacological effective dose than that with other antiallergic drugs. The non-specific pharmacological effect of levocabastine reveals only blepharoptosis. With these pharmacological effects and topical usage, levocabastine was shown to be useful for allergic conjunctive and rhinitis in both seasonal and perennial clinical use.