Captopril also known by the brand name of Capoten, is the first oral drug developed to treat high blood pressure and heart failures, classified under ACE inhibitors and antihypertensive. It act as a competitive inhibitor for angiotensin converting enzyme (ACE) with Ki = 1.7 x 10-9. (Izzo Jr and Weir, 2011). Captopril is often administered together with diuretics to treat chronic hypertension patients.
The drug should be taken orally 3 times daily at the dose of 6.25 - 12.5mg within a day after acute myocardial infarction. The same amount of drug and frequency of administration is also given to treat patients with congestive heart failure (CHF). However, the drug is often taken orally 3 time daily at a dose of 6.25mg when combined with diuretics and digitalis to cure CHF. 50-100mg of the drug is then taken 3 times per day orally for maintenance. To treat retinopathy, diabetes mellitus type 1 and diabetic…show more content… Angiotensin I which has no apparent function can normally be converted into angiotensin II which can constrict blood vessels, increase aldosterone levels and suppress the release of renin. The increase of salt levels will cause an negative feedback mechanism so aldosterone will suppress the release of renin. Also, bradykinin produced from kininogen can dilate blood vessles, cause constriction of bronchiole, and activate afferent vagal fibres. Kinikinase II that is similar to ACE can inactivate Bradykinin. Rate of conversion of arachidonic acid to prostaglandins can be increased by bradykinin, resulting in higher levels of prostacydin and prostaglandin E2, which are both vasodilators. Hence when ACE is administered, angiotensin II will be decreased and at the same time increasing levels of angiotensin I, bradykinin and prostaglandin. Since the angiotensin II that causes vasoconstriction is reduced, blood vessels will dilate, causing blood pressure to fall (Gordon,