Tolerance to anti-pentylenetetrazol effects following chronic diazepam.

Continuous release of diazepam from subcutaneously implanted silastic capsules provided significant protection against pentylenetetrazol seizures in rats for up to 3 weeks. However, the degree of protection seen after 3 weeks of exposure to diazepam was significantly less than after 1 h. These data suggest that continuous exposure to constant low levels of diazepam results in the development of partial tolerance which is not sufficient to eliminate significant anticonvulsant effects.