Glipizide is a second generation sulphonylurea agent that is available in a Gastrointestinal Therapeutic System (GITS)
extended-release formulation.
Glipizide GITS provides more stable plasma
drug concentrations than the immediate-release formulation and the once-daily regimen may optimise patient compliance. In patients with
type 2 diabetes mellitus,
glipizide GITS is at least as effective as the immediate-release formulation of
glipizide in providing glycaemic control, and may have a greater effect on fasting plasma
glucose levels. Any therapeutic advantage over other
antidiabetic agents remains to be established, but in a preliminary report (n = 40)
glipizide GITS provided better glycaemic control and produced less fasting insulinaemia than
glibenclamide (
glyburide). The incidence of hypoglycaemic symptoms with
glipizide GITS is low (< or = 3%). Quality of life was improved compared with baseline after 12 weeks' treatment with
glipizide GITS 5 to 20 mg/day plus diet in a US double-blind, placebo-controlled trial in 569 patients with
type 2 diabetes mellitus. Hyperglycaemic symptom-related distress decreased with
glipizide GITS treatment, while hypoglycaemic symptom-related distress was not significantly increased compared with placebo plus diet. Quality of life during
glipizide GITS treatment has not been compared with that during treatment with other
antidiabetic agents. Monthly productivity losses related to absenteeism were $US91 (1995 values) per patient lower in the
glipizide GITS group compared with the placebo group in the latter prospective study. Productivity parameters improved slightly or did not change significantly in the
glipizide GITS group, but deteriorated in the placebo group. Differences in direct healthcare costs between groups were small and not comprehensively reported.
Glipizide GITS was the least costly strategy for first-line
therapy in a US cost-of-treatment model of the first 3 years after diagnosis of
type 2 diabetes mellitus. The total per-patient cost was $US4867 with
glipizide GITS, $US5196 with
metformin and $US5249 with
acarbose (1996/1997 values). Monthly
drug acquisition costs were lower, and glycosylated haemoglobin levels and patient compliance were improved, after formulary conversion from the immediate-release to the GITS formulation of
glipizide in a US single-hospital retrospective analysis.
CONCLUSIONS:
Glipizide GITS produced better cost outcomes than
metformin and
acarbose in a model of 3 years' treatment of
type 2 diabetes mellitus.
Glipizide GITS had pharmacoeconomic and quality of life advantages over diet alone in the short term, but more clinically relevant comparisons with other
antidiabetic agents are needed. There are limitations to the present data, but the available pharmacoeconomic data have been favourable for
glipizide GITS.