DOC News May 1, 2006
Volume 3 Number 5 p. 5
© 2006 American Diabetes Association
Hypoglycemia Not Likely an Issue With Beta-Blockers
Question: There are so many studies touting the importance of
beta-blockers in people with diabetes. I am concerned about hypoglycemia
unawareness in these patients. How should I address this?
Answer: For many years beta-blockers have been underutilized in
patients with diabetes because of several fears.
In patients with insulin-treated diabetes, some clinicians are concerned
over the effect of beta-blockers reducing or eliminating the warning symptoms
of hypoglycemia. Anthony H. Barnett, MD, and colleagues addressed this concern
in a prospective study of 150 insulin-treated
patients.1 Fifty
insulin-treated subjects taking beta-blockers were compared with 100
insulin-treated subjects not on
beta-blockers.
The patients kept a diary recording all episodes of hypoglycemia and all
warning symptoms. The incidence of loss of consciousness from hypoglycemia was
the same in both groups and was not related to the dose of beta-blocker used.
All symptoms of hypoglycemia were similar in both groups, with the exception
of diaphoresis (perspiration), which was more common in the beta-blocker
group. Diaphoresis is a dramatic symptom, and it makes patients aware of a
sudden change in their blood glucose.
In another study, patients with diabetes on beta-blockers were given
insulin infusions to drop their blood glucose and symptoms were
recorded.2 The
patients on beta-blockers did not have hypoglycemic unawareness. They did have
adrenergic symptoms at lower blood glucose levels than the control subjects
who were not on beta-blockers, but their overall symptom scores were greater
because of an increased perception of diaphoresis in the patients treated with
beta-blockers.
In a retrospective cohort study, more than 13,000 patients with diabetes
who were treated with either oral hypoglycemic drugs or insulin were studied
as to whether antihypertensive agents predisposed them to serious hypoglycemic
events.3 No class of
antihypertensive medication (including beta-blockers) was found to predispose
treated patients with diabetes to serious hypoglycemic events.
The theoretical concerns of hypoglycemia unawareness and blunted
hypoglycemic response do not appear to be clinically important. Patients with
diabetes treated with beta-blockers are no more likely to have serious
hypoglycemic events than those not treated with beta-blockers.
The symptom of diaphoresis—which is more common in hypoglycemic
patients on beta-blockers—may actually make these patients more aware of
their hypoglycemia. Clinicians should feel comfortable prescribing
beta-blockers in patients with diabetes. 
Footnotes
| |
Douglas S. Paauw, MD, is professor of medicine and Rathman Family
Foundation Chair in patient-centered clinical education at the University of
Washington School of Medicine in Seattle.
|
|
References
1. Barnett AH, Leslie D, Watkins PJ: Can insulin-treated diabetics be
given beta-adrenergic blocking drugs? Br Med J 280: 976–978, 1980.[Medline]2. Hirsch IB, Boyle PJ, Craft S, et al.: Higher glycemic thresholds
for symptoms during beta-adrenergic blockade in IDDM.
Diabetes 40:1177–1186, 1991.[Abstract]
3. Shorr RI, Ray WA, Daugherty JR, et al.: Antihypertensives and the
risk of serious hypoglycemia in older persons using insulin or sulfonylureas.
JAMA 278:40–43, 1997.[Abstract]
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