The effect of 2 sympatholytic medications--propranolol and clonidine--on sleep bruxism: experimental randomized controlled studies.
OBJECTIVE
To examine whether 2 sympatholytic medications decrease sleep bruxism and prevent the rise in sympathetic activity preceding the onset of sleep bruxism: propranolol, a nonselective adrenergic beta-blocker, and clonidine, a selective alpha2-agonist.


METHODS
Experimental randomized controlled crossover studies with placebo and active treatments (propranolol 120 mg; clonidine 0.3 mg).


METHODS
Hospital-based sleep research laboratory.


METHODS
Twenty-five subjects with a history and diagnosis of SLEEP BRUXISM (11 men, 14 women; age range, 21 to 31 years).


METHODS
Polygraphic study.


RESULTS
Polygraphic sleep laboratory recordings were done for 4 nights: the first night was habituation, the second, sleep bruxism diagnosis; and 3 and 4 were study nights. The sleep bruxism index was estimated using masseter muscle activity. Heart rate variability was estimated with spectral analysis of RR intervals. Sleep and sleep bruxism variables were not significantly influenced by propranolol. A reduction of the mean RR intervals and of the sympathetic dominance (p < .05) was seen. Under clonidine, duration of sleep stage 2 was prolonged, whereas REM sleep was suppressed in 14 of 16 subjects with sleep bruxism. The sleep bruxism index was reduced by 61% (p < .05). Under clonidine, a reduction in heart rate and sympathetic dominance was observed in stable sleep and in the minute preceding the onset of sleep bruxism (p < .05).


CONCLUSIONS
Although propranolol did not affect sleep bruxism, clonidine decreased sympathetic tone in the minute preceding the onset of sleep bruxism, thus reducing sleep bruxism by preventing the sequence of autonomic to motor activation of sleep bruxism. This further supports the role of sympathetic activity in the pathophysiology of sleep bruxism. Because morning hypotension was seen in 19% of patients, further dose-dependant research is required to assess the safety of clonidine for the management of sleep bruxism.
Faculte de médecine, Université de Montréal, Québec, Canada.
Nelly
N
Huynh
Gilles J
GJ
Lavigne
Paola A
PA
Lanfranchi
Jacques Y
JY
Montplaisir
Jacques
J
de Champlain
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D017286:Polysomnography; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D020186:Sleep Bruxism / Q000188:drug therapy*
D000316:Adrenergic alpha-Agonists; D000319:Adrenergic beta-Antagonists; D011433:Propranolol; D003000:Clonidine