Anti-hypertensive Drugs Flashcards
Hypertension is defined as:
BP>140/90 mmHg
Etiology of hypertension:
90% idiopathic, primary (udk the causes)
10% by specific cause, narrowing of artery, secondary
What are some complications of hypertension?
- Congestive heart failure
- Ischemia
- Myocardial infarction
- Renal damage
- Cerebrovascular accidents (stroke)
Name some anti-hypertensive drugs:
- Diuretics
- β-blocker e.g. propranolol
- ACE inhibitors
- Calcium channel blockers
Name some diuretics.
- Thiazides
- Loop diuretics
What is the difference between thiazides and loop diuretics
Thiazides decrease the urinary excretion of calcium, while loop-diuretics have the opposite effect.
How do loop diuretics work?
Loop diuretics work to lower the fluid buildup in the body by reducing sodium reabsorption in the loop of Henle, thereby causing the elimination of water and sodium from the body.
- acts at TAL (thick ascending limb)
- more potent than thiazide, often used for chronic renal/heart failure
How do thiazides work?
(Mechanism of action)
- Inhibit NaCl reabsorption by blocking Na+/Cl- transporter at DCT=> decreases blood volume & bp
- Enhance Ca2+ reabsorption at DCT
- Enhances urea reabsorption & inhibit excretion at PCT => diurtetic-induced hyperuricemia (predisposes for gout)
- action depends on renal PG synthesis (NSAIDs decrease PG synthesis, interfere w thiazides action)
Diuretics are used to treat:
- Hypertension
- Congestive heart failure
Adverse effects of thiazides:
- Hypokalemia
- Hyponatremia
- Hyperglycemia
- Hyperlipidemia
- Hyperuricemia
- Hypercalcemia
+ contraindicated in gout & diabetes
Name some β-blockers.
- Propranolol (non-selective)
- Atenolol (β1-selective)
Mechanism of action of β blockers:
Decreased heart rate & force, decreased BP
β blockers used to treat:
- Hypertension
- Angina (heart pain)
- Following myocardial infarction
What are some adverse effects of β blockers?
- Bradycardia
-
Bronchospasm
- cuz propranolol is non-selective, it blocks β2 adrenoceptors - Sedation/vivid dream
+ contraindicated in those w asthma
What are some contraindications for β blockers?
- Hypoglycemia
- β blockers will mask signs of hypoglycemia e.g. increased heart rate - Bradycardia
- Asthma (esp non-selective β blockers, propranolol)
- Diabetes
Name some ACE inhibitors (angiotensin converting enzyme inhibitors)
Lisinopril, Enalapril, Captopril
Mechanism of ACE inhibitors?
- Decrease in ANG II by blocking conversion form ANG I
- decrease in vasoconstriction => decrease in peripheral vascular resistance => decrease bp
- decreased aldosterone => decrease Na+ & H2O retention => decreased blood vol => decreased bp - Increased bradykinin by preventing breakdown => decreased PG & NO => increased vasodilation => decreased bp
Uses of ACE inhibitors:
- Hypertenison
- Cardiac failure
- Following myocardial infarction
What are some adverse effects of ACE inhibitors:
- Severe hypotension
- Hyperkalemia: decreased aldosterone => decreased K+ excretion
- Angioedema: bradykinin causes vasodilation & increased permeability
- Dry cough: accumulation of bradykinin
- Acute renal failure
+ contraindicated in pregnancy, esp in eclampsia (fetal renal damage)
