Molecule

Drug Groups

approved

Description

Perindopril is a nonsulfhydryl prodrug that belongs to the angiotensin-converting enzyme (ACE) inhibitor class of medications. It is rapidly metabolized in the liver to perindoprilat, its active metabolite, following oral administration. Perindoprilat is a potent, competitive inhibitor of ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Perindopril may be used to treat mild to moderate essential hypertension, mild to moderate congestive heart failure, and to reduce the cardiovascular risk of individuals with hypertension or post-myocardial infarction and stable coronary disease.

Indication

For the treatment of mild to moderate essential hypertension, mild to moderate congestive heart failure, and to reduce the cardiovascular risk of individuals with hypertension or post-myocardial infarction and stable coronary disease.

Pharmacology

Perindopril is a nonsulfhydryl prodrug that is metabolized via first pass effect (62%) and systemic hydrolysis (38%) to perindoprilat, its active metabolite, following oral administration. Perindoprilat lowers blood pressure by antagonizing the effect of the RAAS. The RAAS is a homeostatic mechanism for regulating hemodynamics, water and electrolyte balance. During sympathetic stimulation or when renal blood pressure or blood flow is reduced, renin is released from the granular cells of the juxtaglomerular apparatus in the kidneys. In the blood stream, renin cleaves circulating angiotensinogen to ATI, which is subsequently cleaved to ATII by ACE. ATII increases blood pressure using a number of mechanisms. First, it stimulates the secretion of aldosterone from the adrenal cortex. Aldosterone travels to the distal convoluted tubule (DCT) and collecting tubule of nephrons where it increases sodium and water reabsorption by increasing the number of sodium channels and sodium-potassium ATPases on cell membranes. Second, ATII stimulates the secretion of vasopressin (also known as antidiuretic hormone or ADH) from the posterior pituitary gland. ADH stimulates further water reabsorption from the kidneys via insertion of aquaporin-2 channels on the apical surface of cells of the DCT and collecting tubules. Third, ATII increases blood pressure through direct arterial vasoconstriction. Stimulation of the Type 1 ATII receptor on vascular smooth muscle cells leads to a cascade of events resulting in myocyte contraction and vasoconstriction. In addition to these major effects, ATII induces the thirst response via stimulation of hypothalamic neurons. ACE inhibitors inhibit the rapid conversion of ATI to ATII and antagonize RAAS-induced increases in blood pressure. ACE (also known as kininase II) is also involved in the enzymatic deactivation of bradykinin, a vasodilator. Inhibiting the deactivation of bradykinin increases bradykinin levels and may sustain the effects of perindoprilat by causing increased vasodilation and decreased blood pressure.

Toxicity

The most likely symptom of overdose is severe hypotension. The most common adverse effects observed in controlled clinical trials include cough, digestive symptoms, fatigue, headache, and dizziness.

Affected Organisms

Biotransformation

Extensively metabolized, with only 4-12% of the dose recovered in urine following oral administration. Six metabolites have been identified: perindoprilat, perindopril glucuronide, perindoprilat glucuronide, a perindopril lactam, and two perindoprilat lactams. Only perindoprilat is pharmacologically active. Peridoprilat and perindoprilat glucuronide are the two main circulating metabolites.

Absorption

Rapidly absorbed with peak plasma concentrations occurring approximately 1 hour after oral administration. Bioavailability is 65-75%. Following absorption, perindopril is hydrolyzed to perindoprilat, which has an average bioavailability of 20%. The rate and extent of absorption is unaffected by food. However, food decreases the extent of biotransformation to peridoprilat and reduces its bioavailability by 35%.

Half Life

Perindopril, 1.2 hours; Peridoprilat, 30-120 hours. The long half life of peridoprilat is due to its slow dissociation from ACE binding sites.

Protein Binding

Perindoprilat, 10-20% bound to plasma proteins

Elimination

Perindopril is extensively metabolized following oral administration, with only 4 to 12% of the dose recovered unchanged in the urine.

Clearance

* 219 - 362 mL/min [oral administration]

References

External Links