doses, symptoms abated within 15–60 minutes. There was little evidence of toxicity from chronic administration of non-lethal doses. These investigators recorded the following acute toxicities, as LD50s for TEA chloride (error ranges not shown): Mouse: 65 mg/kg, i.p.; 900 mg/kg, p.o. Rat: ~56 mg/kg, i.v.; 110 mg/kg, i.m.; 2630 mg/kg, p.o. Dog: ~36 mg/kg, i.v.; 58 mg/kg, i.m. Another research group, working at about the same time, but using tetraethylammonium bromide, published the following LD50 data: Mouse: 38 mg/kg, i.v.; 60 mg/kg, i.p.; >2000 mg/kg, p.o. Rat: 63 mg/kg, i.v.; 115 mg/kg, i.p. Dog: 55 mg/kg, i.v. Rabbit: 72 mg/kg, i.v. Writing in 1950, Graham made some observations on the toxic effects of tetraethylammonium bromide in humans. In one subject, described as a "healthy woman", 300 mg of tetraethylammonium bromide, i.v., produced incapacitating "curariform" (i.e., resembling the effects of tubocurarine) paralysis of the skeletal muscles, as well as marked drowsiness. These effects were largely dissipated within 2 hours. Citing the work of other investigators, Graham noted that Birchall had also produced "alarming curariform effects" in humans with i.v. doses of 32 mg/kg of tetraethylammonium chloride. See also Tetraethylammonium bromide Tetraethylammonium chloride Tetraethylammonium iodide References Neurotoxins Quaternary ammonium compounds Cations