A method for bioassay of physical dependence on sedative drugs in dog.

A method for an economical bioassay of physical dependence on sedatives is presented. Dogs maintained on sodium pentobarbital (200 mg/kg/24 h i.v.) were given periodic graded reductions in maintenance dose, and subscales for measuring signs of abstinence were developed. Using these subscales the relative potencies compared with sodium pentobarbital were determined for sodium secobarbital (RP = 0.85) and methaqualone (RP = 0.14). Sodium thiopental and methaqualone were assayed and found to be equipotent (RP = 0.96) in reducing the signs of abstinence from sodium pentobarbital. The occurrence of convulsions, during periods of complete reduction of the maintenance drug, became less frequent the longer the dogs had been maintained on a constant dose of sodium pentobarbital.