Hypoglycaemia presents important diagnostic and therapeutic problems. Severe and repetitive hypoglycaemic episodes without treatment may be difficult to explain. Failure to identify factitious hypoglycaemia may lead to laparotomy or pancreatectomy [1, 2].

To estimate the prevalence of factitious hypoglycaemia due to sulphonylurea drugs in patients with unexplained severe hypoglycaemia, we conducted a prospective study during the year 2000. Hypoglycaemic patients were recruited throughout France. Plasma was assayed for oral hypoglycaemic agents on the clinician’s request, using h.p.l.c. with u.v. detection. Fifty-six patients with unexplained hypoglycaemia were recruited. In seven of these patients (five women, two men), a sulphonylurea oral hypoglycaemic agent was detected (Table 1).

Table 1.  Plasma concentrations observed.
Hypoglycaemic agentMaximal concentrations observedTherapeutic rangeElimination half-life
Glibenclamide (n = 4)696 µg l−125–50 µg l−15 h−10 h
Glimepiride (n = 2)418 µg l−1  300 µg l−15 h−9 h
Gliclazide (n = 1) 2.1 mg l−1   1.5 mg l−18 h−12 h

Plasma concentrations were usually supra-therapeutic and concentrations up to 15 times the upper limit of the therapeutic range were observed.

In one 45-year-old patient, during hospitalization, we identified glibenclamide concentrations of 529 µg l−1 at 11.00 h (therapeutic concentration 25–50 µg l−1), of 696 µg l−1 at 22.00 h, of 154 µg l−1 at 06.15 h and of 367 µg l−1 at 08.00 h over a 2 day period.

Insulinoma has been suspected in such patients due to continued surreptitious consumption of medication during hospitalization.

Cases of factitious hypoglycaemia from oral hypoglycaemic agents have been published [1–4], and may be a manifestation of Munchausen’s syndrome [5]. Factitious hypoglycaemia due to sulphonylurea drugs should be considered in the differential diagnosis of insulinoma.


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Received •• 2002, accepted 7 August 2002

Thierry Trenque, MD, PhD, Pharmacovigilance Regional Centre, Centre Hospitalier Universitaire, 45 Rue Cognacq-Jay, 51092 Reims Cedex, France. Tel.: +33 3 26 78 77 80; Fax: +33 3 26 78 84 56; E-mail: