myoclonic jerking and drug interaction

I recently had a severe case of myoclonic jerking.  I am taking effexor and took a dose of nyquil the previous night.  Could this combination of drugs and cold medicine cause this condition?

[Brenndy]

Most definitely.  I posted a very unkind opinion regarding Effexor yesterday. Right up there as worst culprit for causing myoclonic jerking (jaw, in particular) is Seroquel.  Friend of mine was on Seroquel, and because of the involuntary jaw movements associated with Seroquel, she chipped her bottom front tooth.  

[ILADVOCATE]

Are you sure your friend does not have tardive dyskinesia? Seroquel and all known antipsychotics with the exception of Clozaril can cause tardive dyskinesia which is irreversible, progressive and can be masked while it is occuring. There are also variants of it such as tardive dystonia and tardive myoclonus, both of which I have and are being treated with multiple medications including Zofran. People need to continue to take antipsychotics but a person who has any abnormal movements that are not classed as temporary (such as akathesia) they should be referred to a movement disorder specialist and if diagnosed a psychiatrist would change them to Clozaril. There are also medications in study such as glycine (which I am on under the care of a psychopharmcologist who will be documenting the results) which is a glutamate antagonists as well as other study classes of medications that can't cause tardive conditions. If your friend stopped taking medication (not advised) and still has abnormal motor movements they should still see a movement disorders specialist for treatment and if they want to know about new antipsychotics in development that can't cause it there is a nationwide symposium where it will be discussed:
http://www.narsad.org/help/campaign/publicannouncement.html