Background Kidney failure (KF) in children and adolescents leads to reduced lifespan and compromised health. Alport syndrome (AS) is a leading hereditary cause of KF in children.…

Renin is an enzyme secreted by the kidneys that plays a critical role in blood pressure regulation and fluid balance by initiating the renin-angiotensin-aldosterone system (RAAS).

Background Kidney failure (KF) in children and adolescents leads to reduced lifespan and compromised health. Alport syndrome (AS) is a leading hereditary cause of KF in children. Angiotensin-convertin...

Skvarc D R, Berk M, Byrne L K, et al. Post-Operative cognitive dysfunction: an exploration of the inflammatory hypothesis and novel therapies. Neurosci

Recent findings on pregnancy outcomes in women with IgA nephropathy (IgAN) suggest pre-conception use of non-renin-angiotensin-aldosterone system inhibitor

The IS is a multifactorial disorder with established risk factors encompassing both modifiable environmental influences and inherent genetic susceptibility.

The largest trial to date of candesartan, an angiotensin receptor blocker, confirms the efficacy of two different doses to alleviate episodic migraine.

mlHsu et al. examine the effectiveness of Angiotensin Receptor-Neprilysin Inhibitors (ARNI) in individuals with Chronic Obstructive Pulmonary Disease (COPD) and heart failure. Findings reveal that ARNI treatment in people with both COPD and HF may lower the risk of COPD exacerbations, respiratory failure, and respiratory tract infections.

Triple Renin-Angiotensin System/Sodium-Glucose Transporter 2/Glycogen Synthase Kinase-3 Beta Inhibition for the Progression of CKD in Col4a3 -/- Mice with Alport Nephropathy

**Angiotensin-Converting Enzyme (ACE) Inhibitors** are a cornerstone in the management of **hypertension, heart failure, and myocardial infarction**. These drugs play a crucial role in controlling the **Renin-Angiotensin-Aldosterone System (RAAS)** , helping to relax blood vessels and improve blood flow throughout the body. ACE inhibitors are easily identified by their common suffix **“-pril”** , which includes drugs such as **Captopril, Enalapril, and Lisinopril**. Let’s explore the **mechanism, uses, adverse effects, contraindications, and key mnemonics** in a student-friendly format. ## Classification **Category**| **Type** ---|--- Pharmacologic (P)| ACE Inhibitors Therapeutic (T)| Antihypertensives ### Common ACE Inhibitors: * **Captopril** * **Enalapril** * **Lisinopril** * **Ramipril** * **Perindopril** * **Benazepril** All end with the suffix **“-pril”** , which makes them easy to remember. ## Mechanism of Action (MOA) ACE inhibitors act by **blocking the conversion of Angiotensin I to Angiotensin II**. ### Step-by-step mechanism: 1. Normally, the **Angiotensin-Converting Enzyme (ACE)** converts **Angiotensin I → Angiotensin II** , a potent **vasoconstrictor**. 2. By **inhibiting ACE** , these drugs prevent the formation of Angiotensin II. 3. As a result: * **Blood vessels relax (vasodilation)** * **Aldosterone secretion decreases** → Less sodium and water retention * **Blood volume and pressure drop** Additionally, ACE inhibitors prevent the breakdown of **bradykinin** , a compound that promotes vasodilation — this enhances the blood-pressure-lowering effect but can also cause the well-known **“ACE cough.”** ** ** ## Clinical Uses ACE inhibitors are prescribed for a range of cardiovascular and renal conditions: **1. Hypertension (High Blood Pressure)** – First-line agents, especially in young or diabetic patients. **2. Heart Failure** – Improve survival by reducing cardiac workload and preventing remodeling. **3. Myocardial Infarction (Heart Attack)** – Prevent further cardiac damage and remodeling post-MI. **4. Diabetic Nephropathy** – Protect the kidneys by lowering glomerular pressure. **5. Chronic Kidney Disease (CKD)** – Slow down disease progression and reduce proteinuria. ## Adverse Effects – Remember with the Mnemonic **“APRIL”** Since all ACE inhibitors end in **“PRIL”** , the mnemonic **APRIL** helps recall their key side effects: **Letter**| **Adverse Effect**| **Explanation** ---|---|--- **A**| Angioedema| Swelling of lips, face, or tongue due to increased bradykinin. **P**| Potassium Elevated| Reduced aldosterone → potassium retention → **hyperkalemia**. **R**| Recurrent Cough| Due to bradykinin buildup in the lungs. **I**| Itchy Skin| Mild allergic or vasodilatory reaction. **L**| Low Blood Pressure| From decreased vascular resistance and fluid loss. **Mnemonic tip:** > “APRIL” = Side effects of “-pril” drugs. ## Drug Interactions **Drug**| **Interaction Effect** ---|--- **Diuretics**| Increase risk of **hypotension** (especially first dose). **Lithium**| Increases **lithium toxicity** due to reduced clearance. **NSAIDs**| May reduce the **antihypertensive effect** by interfering with kidney function. Monitoring is essential when combining ACE inhibitors with these agents. ## Contraindications ACE inhibitors should **not** be used in the following conditions: **1. Pregnancy** – Can cause fetal injury, especially in the second and third trimesters. **2. Impaired Renal Function** – May worsen renal insufficiency, particularly in bilateral renal artery stenosis. **3. Hypotension** – May cause dangerous drops in blood pressure. **4. History of Angioedema** – Increased risk of recurrence. ## Black Box Warning **“Increased risk of fetal injury or death when administered during pregnancy.”** Hence, **ACE inhibitors are contraindicated in pregnant women** and those planning pregnancy. ## Advantages of ACE Inhibitors * Effective in **reducing mortality** in heart failure and post-MI. * Provide **renal protection** in diabetic patients. * Do **not cause reflex tachycardia** , unlike some other antihypertensives. * Improve **cardiac remodeling** by reducing afterload and preload. ## ACE Inhibitors vs. ARBs (Angiotensin II Receptor Blockers) **Feature**| **ACE Inhibitors (“-pril”)**| **ARBs (“-sartan”)** ---|---|--- **Mechanism**| Block conversion of Angiotensin I → II| Block Angiotensin II receptor **Bradykinin Effect**| Increased (causes cough, angioedema)| None (no cough) **Common Side Effect**| Dry cough| Rare angioedema **Preferred When**| First-line for hypertension| Patient is intolerant to ACE inhibitor cough **Suffix**| “-pril”| “-sartan” Both classes lower blood pressure but differ in side effect profiles. ## Clinical Monitoring While on ACE inhibitors, patients should undergo regular checks for: * **Serum potassium** → to detect hyperkalemia * **Serum creatinine** → to monitor kidney function * **Blood pressure** → to adjust dosing if needed ## Summary Table **Parameter**| **Details** ---|--- **Drug Class**| Angiotensin-Converting Enzyme (ACE) Inhibitors **Common Drugs**| Captopril, Enalapril, Lisinopril **Mechanism**| Blocks conversion of Angiotensin I → II; reduces RAAS activity **Uses**| Hypertension, Heart Failure, Myocardial Infarction, Diabetic Nephropathy **Mnemonic for Adverse Effects**| **APRIL** = Angioedema, Potassium ↑, Recurrent cough, Itchy skin, Low BP **Interactions**| Diuretics (hypotension), Lithium (toxicity) **Contraindications**| Pregnancy, Renal impairment, Hypotension **Black Box Warning**| Fetal injury during pregnancy ## FAQs About ACE Inhibitors #### **Q1. Why are ACE inhibitors preferred for diabetic patients?** They reduce intraglomerular pressure and proteinuria, offering kidney protection in diabetes. #### **Q2. Why do ACE inhibitors cause cough?** Because they increase **bradykinin** levels, which can irritate the respiratory tract. #### **Q3. Which suffix helps identify ACE inhibitors?** All ACE inhibitors end with **“-pril”** , such as Captopril and Lisinopril. #### **Q4. What should patients avoid while taking ACE inhibitors?** Avoid **potassium supplements** or **potassium-sparing diuretics** , as these may cause hyperkalemia. #### **Q5. What’s the difference between ACE inhibitors and ARBs?** ACE inhibitors block enzyme conversion; ARBs block receptor binding. ARBs do not cause a cough.

ACE inhibitors such as Captopril, Enalapril, and Lisinopril. Mechanism of action, uses, side effects (APRIL mnemonic), and contraindications.

**Angiotensin II Receptor Blockers (ARBs)** are a vital class of antihypertensive medications that help manage **high blood pressure, heart failure, and stroke prevention**. They are often recognized by the suffix **“-sartan”** , with common examples including **Losartan, Irbesartan, and Telmisartan**. These drugs work by blocking the actions of **Angiotensin II** , a potent vasoconstrictor in the **Renin-Angiotensin-Aldosterone System (RAAS)** , thereby promoting relaxation of blood vessels and reducing blood pressure. Let’s explore their **classification, mechanism, clinical applications, side effects, and contraindications** in a clear, student-friendly format. ## Classification **Class**| **Category** ---|--- Pharmacologic (P)| Angiotensin II Receptor Blockers (ARBs) Therapeutic (T)| Antihypertensives Common ARBs include: * **Losartan** * **Irbesartan** * **Telmisartan** * **Valsartan** * **Olmesartan** * **Candesartan** All of these drugs end with the suffix **“-sartan”** , which makes them easy to identify in pharmacology. ## Mechanism of Action (MOA) ARBs **block the binding of Angiotensin II** to its receptors (mainly **AT₁ receptors**) found in **vascular smooth muscle** and **adrenal glands**. ### As a result: **1. Vasoconstriction is inhibited** , leading to **vasodilation**. **2. Aldosterone release decreases** , reducing sodium and water reabsorption in the kidneys. **3. Blood volume and blood pressure fall**. This mechanism helps maintain hemodynamic stability and prevent excessive strain on the heart. In simple terms, **ARBs prevent Angiotensin II from tightening the blood vessels and increasing blood pressure.** ** ** ** ** ## Uses of Angiotensin II Receptor Blockers ARBs are widely prescribed for cardiovascular and renal conditions: **1. Hypertension (High Blood Pressure)** – First-line therapy for patients intolerant to ACE inhibitors. **2. Heart Failure** – Reduces cardiac workload by lowering afterload and preload. **3. Stroke Prevention** – Helps reduce recurrence risk in hypertensive individuals. **4. Diabetic Nephropathy** – Protects kidney function by lowering intraglomerular pressure. **5. Chronic Kidney Disease (CKD)** – Slows disease progression in hypertensive and diabetic patients. ## Mnemonic to Remember ARB Adverse Effects – **“FAIL”** ARBs ensure Angiotensin II effects **FAIL** , but they also come with potential side effects represented by the same mnemonic: **Letter**| **Meaning**| **Explanation** ---|---|--- **F**| Fetal Injury| Can cause developmental harm to the fetus (especially in 2nd and 3rd trimesters). **A**| Angioedema| Rare swelling of lips, face, or throat; similar to ACE inhibitor reaction. **I**| Imbalance of Electrolytes| Can increase potassium (↑K⁺), reduce glucose (↓Glucose), and sodium (↓Na⁺). **L**| Low Blood Pressure| Due to vasodilation and fluid loss. **Mnemonic meaning:** > “The job of Sartans is to make sure the effects of Angiotensin II FAIL.” ## Adverse Effects **Hypotension (Low BP)** – Especially after the first dose in volume-depleted patients. **Hyperkalemia** – Due to reduced aldosterone levels, potassium may accumulate. **Dizziness or Fatigue** – From reduced vascular resistance. **Angioedema** – Rare but potentially life-threatening. **Renal Impairment** – In susceptible individuals with renal artery stenosis. ## Drug Interactions **Drug**| **Interaction Effect** ---|--- **Lithium**| Increases risk of **lithium toxicity** due to reduced renal clearance. **NSAIDs**| Reduce the **antihypertensive effect** of ARBs by affecting renal prostaglandins. Therefore, co-administration with these agents must be monitored carefully. ## Contraindications ARBs are contraindicated in: **1. Pregnancy** – Can cause **fetal toxicity** and malformations (especially after the first trimester). **2. Severe Renal Impairment** – May worsen kidney function in patients with bilateral renal artery stenosis. **3. Hypersensitivity** – To any ARB component. ## Black Box Warning **“Increased risk of fetal injury or death when used during pregnancy.”** Pregnant women or those planning pregnancy should **avoid ARBs** and consult their physician for safer alternatives. ## Comparison: ARBs vs ACE Inhibitors **Feature**| **ARBs (e.g., Losartan)**| **ACE Inhibitors (e.g., Enalapril)** ---|---|--- **Mechanism**| Block Angiotensin II receptors| Block conversion of Angiotensin I → II **Cough**| Rare| Common (due to bradykinin accumulation) **Angioedema**| Rare| More common **Preferred For**| ACE inhibitor–intolerant patients| First-line hypertension management **Suffix**| “–sartan”| “–pril” **Summary:** > ARBs provide similar benefits to ACE inhibitors but with fewer side effects, especially the absence of a dry cough. ## Clinical Pearls * Always monitor **serum potassium and creatinine levels** during therapy. * Avoid **potassium supplements or potassium-sparing diuretics** unless prescribed. * ARBs are especially beneficial in **diabetic patients** due to renal protective effects. * May be combined with **thiazide diuretics** for better blood pressure control. ## Summary Table **Parameter**| **Details** ---|--- **Drug Class**| Angiotensin II Receptor Blockers (ARBs) **Common Drugs**| Losartan, Irbesartan, Telmisartan, Valsartan **Mechanism**| Block Angiotensin II receptor → vasodilation + ↓Aldosterone **Uses**| Hypertension, Heart Failure, Stroke prevention, Diabetic nephropathy **Mnemonic for Adverse Effects**| **FAIL** – Fetal injury, Angioedema, Imbalance of electrolytes, Low BP **Interactions**| Lithium (↑toxicity), NSAIDs (↓effect) **Contraindications**| Pregnancy, Renal impairment **Black Box Warning**| Fetal injury during pregnancy ## FAQs About ARBs #### **Q1. What are Angiotensin II Receptor Blockers used for?** They are mainly used to treat **hypertension** , **heart failure** , and **to protect the kidneys** in diabetic patients. #### **Q2. How do ARBs differ from ACE inhibitors?** ARBs block the **receptor** of Angiotensin II, while ACE inhibitors block its **formation**. ARBs cause fewer side effects like cough. #### **Q3. Why should ARBs be avoided during pregnancy?** Because they can lead to **fetal renal damage, low amniotic fluid, or even fetal death**. #### **Q4. Do ARBs cause cough like ACE inhibitors?** No, ARBs do **not** cause cough because they do not increase bradykinin levels. #### **Q5. Which suffix helps identify ARBs?** All ARBs end with the suffix **“-sartan”** , such as Losartan, Telmisartan, and Irbesartan.

Angiotensin II Receptor Blockers (ARBs) - Mechanism of action, clinical uses, adverse effects, contraindications, and the “FAIL” mnemonic.

Renin-Angiotensin-Aldosterone System (RAAS) maintains blood pressure and fluid balance. Easy explanation with steps, hormones, and diagrams.