Clinical pharmacological aspects of dihydroergotamine timed release: activity on monoamine venospasm

Using the computerized venotest, it is possible to evaluate both the venospastic activity of the vasoactive monoamines (NA,5-HT, DA) and the effects of the relative agonistic and antagonistic drugs. The ergot-derivatives are 5-HT and NA agonists at low doses, and are 5-HT antagonists at high doses. Dihydroergotamine timed release (DHE-TR) administered orally is capable at 12 hours following the last administration of producing a significant increase of 5-HT and NA venospasm. It is hypothesized that 12 hours after the last administration of DHE-TR, hematic concentrations, corresponding to clinical and therapeutic levels, capable of potentiating the monoamine venospasm still exists.