ORTHOSTATIC HYPOTENSION WHEN COMBINED WITH CALCIUM CHANNEL BLOCKERS, ANTIHYPERTENSIVES, PHENOTHIAZINES, TRICYCLIC ANTIDEPRESSANTS. ALCOHOL MAY PRODUCE SEVERE HYOTENSION & COLLAPSE. INCREASES BIOAVILABILITY OF DIHYDROERGOTAMINE. SILDENAFIL USE MAY CAUSE PROFOUND HYPOTENSION & DEATH HAS BEEN REPORTED WHICH MAY BE DUE TO SOME POSSIBLE DRUG INTERACTION.