Heres what I found, but you really should ask your obgyn.
Immuneosuppressant drugs (such as imuran) have not been studied as to the effects of it on pregnancy.
Effexor may be at this stage, but it if you continue into the third tri, your baby will become addicted to effexor.
Lamictal, unknown.
Duragesic patches, unknown.
Myobloc injections, only if it is absolutely needed.
But like I said, you need to talk with your obgyn about this so you can either know youa re on the drug safely, or a safe alternative :)