This is a prescription drug used to treat depression (it is classed as a tricyclic antidepressant and is sold under trade names such as Elavil and Endep). It may cause a wide range of side effects, including rashes, nausea, weight gain/loss, drowsiness, nervousness, insomnia, confusion, seizures, coma, etc.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.