Ramipril

Absorption

The extent of absorption is at least 50-60%.. Food decreases the rate of absorption from the GI tract without affecting the extent of absorption. The absolute bioavailabilities of ramipril and ramiprilat were 28% and 44%, respectively, when oral administration was compared to intravenous administration. The serum concentration of ramiprilat was unchanged when capsules were opened and the contents dissolved in water, dissolved in apple juice, or suspended in apple sauce.

Toxicity

Symptoms of overdose may include excessive peripheral vasodilation (with marked hypotension and shock), bradycardia, electrolyte disturbances, and renal failure. Cases of ACE inhibitor induced hepatotoxicity have been reported in humans and presented as acute jaundice and elevated liver enzymes. Removal of the ACE inhbitor resulted in a decline in liver enzymes and re-challenge produced a subsequent increase.
There were no observed tumerogenic effects at chronic doses up to 500mg/kg/day to rats for 24 months or at doses up to 1000mg/kg/day to mice for 18 months. For both species doses were administered by gavage and equivalent to 200 time the maximum recommended human exposure based on body surface area.
No mutagenic activity was detected in the Ames test in bacteria, the micronucleus test in mice, unscheduled DNA synthesis in a human cell line, or a forward gene-mutation assay in a Chinese hamster ovary cell line. Several metabolites of ramipril also produced negative results in the Ames test.
No effects on fertility were seen in rats at doses up to 500mg/kg/day. No teratogenicity was observed in rats and cynomolgus monkeys at doses 400 times the maximum recommended human exposure nor in rabbites at 2 times the maximum recommended human exposure.
LD50 10 g/kg (rat). LD50 10.5 g/kg (mouse). LD50 1 g/kg (dog).

Description

Ramipril, a prodrug of ramiprilat, is a long-acting, tissue-specific and non-sulfhydryl ACE inhibitor useful in the treatment of mild to moderate hypertension. In animal studies ramipril exerted cardioprotective effects resembling those of bradykinin in cardiac reperfusion injuries. Ramipril is also reportedly useful in congestive heart failure.

Chemical properties

White Solid

Originator

Hoechst AG (W. Germany)

The Uses of Ramipril

Angiotensin-converting enzyme (ACE) removes the C-terminal dipeptide from angiotensin I to form angiotensin II, a powerful vasoconstrictor. ACE is a key regulator of the renin-angiotensin system and an important drug target for the treatment of hypertension, congestive heart failure, and heart attacks, and also in preventing renal and retinal complications in diabetes. Ramipril is a second generation ACE inhibitor (IC50 = 4 nM) that acts as a prodrug, which is hydrolyzed in vivo to the active metabolite ramiprilat. The antihypertensive and cardioprotective efficacy of ramipril has been demonstrated in large-scale noncomparative studies and clinical trials.[Cayman Chemical]

The Uses of Ramipril

An antihypertensive. An angiotensin converting enzyme (ACE) inhibitor, converted to active, diacid metabolite

The Uses of Ramipril

cardiotonic

The Uses of Ramipril

An inhibitor of the angiotensin- coverting enzyme (ACE)

Background

Ramipril is a prodrug belonging to the angiotensin-converting enzyme (ACE) inhibitor class of medications. It is metabolized to ramiprilat in the liver and, to a lesser extent, kidneys. Ramiprilat 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). Ramipril may be used in the treatment of hypertension, congestive heart failure, nephropathy, and to reduce the rate of death, myocardial infarction and stroke in individuals at high risk of cardiovascular events.

Indications

For the management of mild to severe hypertension. May be used to reduce cardiovascular mortality following myocardial infarction in hemodynamically stable individuals who develop clinical signs of congestive heart failure within a few days following myocardial infarction. To reduce the rate of death, myocardial infarction and stroke in individuals at high risk of cardiovascular events. May be used to slow the progression of renal disease in individuals with hypertension, diabetes mellitus and microalubinuria or overt nephropathy.

What are the applications of Application

Ramipril is an inhibitor of the angiotensin- coverting enzyme (ACE)

definition

ChEBI: A dipeptide that is the prodrug for ramiprilat, the active metabolite obtained by hydrolysis of the ethyl ester group. An angiotensin-converting enzyme (ACE) inhibitor, used to treat high blood pressure and congestive heart failure.

brand name

Altace (King);Triatec.

General Description

Ramipril, (2S, 3aS, 6aS)-1-[(S)-N-[(S)-1-carboxy-3-phenylpropyl]alanyl]octahydrocyclopenta[b]-pyrrole-2-carboxylic acid 1-ethyl ester (Altace), ishydrolyzed to ramiprilat, its active diacid form, faster thanenalapril is hydrolyzed to its active diacid form. Peak serumconcentrations from a single oral dose are achieved between1.5 and 3 hours. The ramiprilate formed completely suppresses ACE activity for up to 12 hours, with 80% inhibitionof the enzyme still observed after 24 hours.

Biochem/physiol Actions

Angiotensin converting enzyme (ACE) inhibitor.

Pharmacokinetics

Ramipril is an ACE inhibitor similar to benazepril, fosinopril and quinapril. It is an inactive prodrug that is converted to ramiprilat in the liver, the main site of activation, and kidneys. Ramiprilat confers blood pressure lowing effects 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 ramiprilat by causing increased vasodilation and decreased blood pressure.

Clinical Use

Angiotensin-converting enzyme inhibitor:
Hypertension
Secondary prevention of myocardial infarction (MI), stroke or cardiovascular death
Heart failure
Diabetic nephropathy

Veterinary Drugs and Treatments

Ramipril is a long-acting angiotensin converting enzyme (ACE) inhibitor that may be useful in treating heart failure or hypertension in dogs or cats. It is an approved product in the UK for treating heart failure in dogs. In cats, ramipril has been used for treating arterial hypertension. A recent study (MacDonald, Kittleson et al. 2006) did not show any significant benefit using ramipril in treating Maine Coon cats with hypertrophic cardiomyopathy without heart failure.
Like other ACE inhibitors, it may potentially be useful as adjunctive treatment in chronic renal failure and protein losing nephropathies. In dogs with moderate renal impairment (such as might be found with CHF), there is apparently no need to adjust ramipril dosage.

Drug interactions

Potentially hazardous interactions with other drugs
Anaesthetics: enhanced hypotensive effect.
Analgesics: antagonism of hypotensive effect and increased risk of renal impairment with NSAIDs; hyperkalaemia with ketorolac and other NSAIDs.
Antihypertensives: increased risk of hyperkalaemia, hypotension and renal failure with ARB’S and aliskiren.
Bee venom extract: possible severe anaphylactoid reactions when used together.
Ciclosporin: increased risk of hyperkalaemia and nephrotoxicity.
Cytotoxics: increased risk of angioedema with everolimus.
Diuretics: enhanced hypotensive effect; hyperkalaemia with potassium-sparing diuretics.
ESAs: increased risk of hyperkalaemia; antagonism of hypotensive effect.
Gold: flushing and hypotension with sodium aurothiomalate.
Lithium: reduced excretion (possibility of enhanced lithium toxicity).
Potassium salts: increased risk of hyperkalaemia.
Tacrolimus: increased risk of hyperkalaemia and nephrotoxicity

Metabolism

Hepatic metabolism accounts for 75% of total ramipril metabolism. 25% of hepatic metabolism produces the active metabolite ramiprilat via liver esterase enzymes. 100% of renal metabolism converts ramipril to ramiprilat. Other metabolites, diketopiperazine ester, the diketopiperazine acid, and the glucuronides of ramipril and ramiprilat, are inactive.

Metabolism

Ramipril is metabolised in the liver to its active metabolite, ramiprilat, and other inactive metabolites. It is excreted mainly in the urine, as ramiprilat, other metabolites, and some unchanged drug. About 40% of an oral dose appears in the faeces; this may represent both biliary excretion and unabsorbed drug.

storage

Store at +4°C