Many people have reported that they felt calm when taking parasite drugs such as Vermox. I do know from reading that Alinia is 99% protein bound as the delivery system which may explain its neurological behavior (?).
Theory #2 :: It is quite possible that it was killing off the bad guys. When infections rage out of control many biochemical events occur (major endocrinological shifts), one of which is Substance P which is a neurotransmitter, the P stands for Pain (seriously). http://en.wikipedia.org/wiki/Substance_P