Abstract
To evaluate the effects of a muscle reluxant, Tizanidine, on intramuscular pressure of the paraspinal muscules, 16 patients with lumbosacral diseases (at the mean age of 60 years, range 30 to 74) were examined. Tizanidine was orally administered at a dose of 2mg. Intramuscular pressure was measured before and 30 minutes after administration using slit catheter transducer technique during lying (supine and prone). standing (neutral, flexion and extension) and walking.
In lying positions and walking, the mean intramuscular pressures after administration were significantly lower (p<0.05) than those before administration. During standing, intramuscular pressures decreased after administration although it was not statistically significant.
The patterns of intramuscular pressure during walking were classified into following five types: stable, unstable, waxing, waning and miscellaneous. The stable pattenrs was observed in six patients before administration and in nine patients after, and three patients with waxing pattern before administration presented either stable or waning pattern after intake of Tizanidine.
In conclusion, Tizanidine decrease the pressure in the paraspinal muscles in lying positions and walking. It also may improve the patters of the pressure of patients with lumbosacral diseases during walking.
