The effect of propranolol on the occurrence of hypoglycaemic symptoms was a
ssessed in insulin-dependent diabetic patients with hypoglycaemia unawarene
ss. A double-blind, randomised parallel group study (2:1 fashion) was condu
cted over 4-week period. The propranolol group (n = 9) received 20 mg (week
1 and 2) and 30 mg (week 3 and 4) twice daily, and the other group (n = 5)
a matched placebo for 4 weeks. Patients included had experienced at least
two severe hypoglycaemic episodes (coma or seizures) during the previous ye
ar, which were characterised by a lack of adrenergic symptoms and required
the assistance of another person. The mean number of hypoglycaemias during
the study period was similar in both groups (placebo : 13 +/- 2 propranolol
: 11 +/- 1), whereas the number of totally asymptomatic hypoglycaemias (<
0.6 g/l) was lower on propranolol than on placebo (3 +/- 1 vs 8 +/- 3, NS)
and the number of symptomatic hypoglycaemias was higher (7.2 +/- 2 vs 4.6 /- 1, NS). Subjective evaluation of treatment by the investigators showed 0
/5 successes in the placebo group and 5/9 in the propranolol group (chi(2)
= 4.32, p = 0.038). The main advantage of propranolol over placebo was an i
ncreased incidence of sweating. The ratio [number of hypoglycaemias with sw
eating/total number of hypoglycaemias] being higher with propranolol (0.28
+/- 0.08 vs 0.06 +/- 0.02. p = 0.06). This pilot study suggests that beta-b
lockers may be useful in restoring adrenergic symptoms during hypoglycaemia
in insulin-dependent diabetic patients without warning symptoms of hypogly
caemia. This beneficial effect seems to be predominantly related to an incr
ease in hypoglycaemia-induced sweating. A larger study is needed to confirm
or invalidate these preliminary results.