ACEi & ARB

• ACE inhibitors were first discovered in the 1970s by researchers studying snake venom. They found that the venom contained a protein that could block the activity of ACE. This led to the development of captopril, which was approved for use in the United States in 1981.

Captopril, the first ACEi

A little bit of History

ARBs were developed in the 1990s by Merck as an alternative to ACE inhibitors. They were initially used to treat high blood pressure and have since been shown to be effective in treating heart failure and kidney disease as well.

Losartan, the first ARB

Renin-Angiotensin-Aldosteron System

Physiology

• Angiotensin is a peptide hormone, part of the renin–angiotensin system, which regulates blood pressure
• Angiotensinogen -> Angiotensin I -> Angiotensin II

ACEi

• Inhibition of ACE

Angitensin Receptor Blocker

ARB

These substances are AT1-receptor antagonists; that is, they block the activation of angiotensin II AT1 receptors. AT1 receptors are found in smooth muscle cells of vessels, cortical cells of the adrenal gland, and adrenergic nerve synapses.

Some are competitive antagonists and some are insurmountable antagonists. Their affinites to the receptor varies

MI

MI

reduce the risk of death and heart failure after a heart attack, particularly in patients with left ventricular dysfunction.

reducing the workload on the heart

ACEi have been shown to improve hemodynamics, reduce symptoms of fatigue and dyspnea, increase exercise capacity, correct hyponatremia, reduce diuretic requirements and ventricular arrhythmias, and conserve potassium and magnesium

Used to treat compensated, stable congestive HFrF

HF

Cardiovascular protection

Cardiovascular protection

ACE inhibitors potentiate kinin–nitric oxide (NO)–dependent coronary vascular dilation

ACE inhibitors can reduce inflammation by reducing angiotensin 2 pro-inflammaory effect on blood vessels

Treatment of Hypertension

Hypertension

ACEi - First Line

relax the blood vessels and lower blood pressure

used in scleroderma for the same reasons

Diabetic Nephropathy

Diabetic Nephropathy

Vasoconstirction of the efferent arteriole is reduced and less protein crosses the glomerular filter into the tubule of the nephron

Reduce renal blood pressure and affect renal hmodynamic

Pregnancy

Precautions

Contraindications

Renal artery stenosis

ACEi: history of angioedema

Allergy to the drug

ACEi: benazepril, zofenopril, perindopril, trandolapril, captopril

ARB: Losartan (most commonly used), olmesartan, telmisartan, and valsartan

Frequently prescribed ACEi and ARB

ACEi

ARB (Less side effects)

Side Effects

Headache

Hypotension

Cough (Most common)

Dizziness

Diarrhea (Rare)

Hyperkalemia

Dry mouth

Orthstatic Hypotension (Rare)

Angioedema (Rare)

Side Effects

Hyperkalemia

Nauesa

Fatigue

Drug interactions

Drug intercations

Cost

Cost

ARBs are often more expensive than other medications used to treat hypertension, such as ACE inhibitors and diuretics.

Side effects

Like all medications, ARBs can have side effects, including dizziness, fatigue, and headaches. While these side effects are generally mild, they can be more severe in some patients.

Side effects

Safety Concerns

Safety concerns

There have been some safety concerns raised regarding ARBs, particularly in relation to an increased risk of cancer. However, these concerns have not been definitively proven and more research is needed.

Efficacy

Efficacy

While ARBs are effective in reducing blood pressure, they may not be as effective as other medications, particularly in certain patient populations. For example, ACE inhibitors may be more effective in patients with heart failure or diabetes.