TABLE 1

Median effective doses (ED₅₀ values) for galantamine, donepezil, rivastigmine, and (±)huperzine A in preventing the lethality of 1.5 × LD₅₀ soman in guinea pigs post-treated with atropine (10 mg/kg i.m.)

As described in Materials and Methods, guinea pigs were treated intramuscularly with a given dose of the test drug. Thirty minutes later, the animals were challenged with 1.5 × LD₅₀ soman (42 μg/kg s.c.). One minute after the soman, the animals received an injection of atropine (10 mg/kg i.m.). ED₅₀ values were derived from the probit fitting of the resulting dose-response relationships shown in Figs. 1 to 4. Numbers in parentheses are the 95% confidence intervals.