Occult metoprolol overdose.

A patient with an apparent dilantin and phenobarbital overdose displayed hypotension and oliguria resistant to usual cardiotonic drugs and volume loading. In addition, she required an unusually high dose of epinephrine for resuscitation. Metoprolol, a beta-blocker not included on the drug screen, was subsequently implicated. An overdose of this drug should be suspected in patients whose hypotension is resistant to usually effective doses of inotropic and chronotropic agents.