Mechanism of Action

The a-antagonism produced by prazosin and the other quinazoline derivatives is of the equilibrium-competitive type. The drugs are selective for a1-adrenoceptors, so that at usual therapeutic concentrations there is little or negligible antagonism of a2-adrenoceptors. However, selectivity is only relative and can be lost with high drug concentrations. While most of the pharmacological effects of prazosin are directly attributable to a1-antago-nism, at high doses the drug can cause vasodilation by a direct effect on smooth muscle independent of a-recep-tors. This action appears to be related to an inhibition of phosphodiesterases that results in an enhancement of intracellular levels of cyclic nucleotides.

Was this article helpful?

0 0
Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook

Post a comment