Pharmacological Actions

Treatment with captopril reduces blood pressure in patients with renovascular disease and in patients with essential hypertension. The decrease in arterial pressure is related to a reduction in total peripheral resistance. Most studies demonstrate a good correlation between the hypotensive effect of inhibitors and the degree of blockade of the renin-angiotensin system. Many of the pharmacological effects of captopril are attributable to the inhibition of angiotensin II synthesis. However, ACE is a relatively nonselective enzyme that also ca-tabolizes a family of kinins to inactive products (Fig. 18.4). Bradykinin, one of the major kinins, acts as a vasodilator through mechanisms related to the production of nitric oxide and prostacyclin by the vascular en-dothelium. Thus, administration of the ACE inhibitor captopril not only inhibits angiotensin II production but also prevents the breakdown of bradykinin. Increases in bradykinin concentrations after administration of ACE inhibitors contribute to the therapeutic efficacy of these compounds in the treatment of hypertension and congestive heart failure. However, alterations in bradykinin

1 Propranolol |

j Methyldopa I

I Indomethacin I

1 Propranolol |

j Methyldopa I

I Indomethacin I

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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