Antihypertensive Drugs Flashcards
What is one of the biggest influences on peripheral resistance
The radius of the arteriole
What are some factors influencing the radius of arterioles
Adrenaline
Noradrenaline
Ang II
Endothelial factors
Angiotensin Converting Enzyme (ACE) Inhibitions and Ang II Receptor Blockers
- Used for treatment of high blood pressure and chronic heart failure
- Reduce the activity of the renin -angiotensin-aldosterone system by inhibiting the formation of Ang II
What does the inhibition of the converting enzyme lead to
- Decreased conversion of Ang I and Ang II
- Reduced plasma aldosterone levels
Physiological effects of ACE inhibitors
- Vasodilation - decreased after load
- Decreased Na/Water retention
- Reduced vascular remodelling
- Reduced cardiac remodelling
Why is tissue remodelling bad
it leads to negative long term problems in the blood vessels and the heart
The 3 ACE inhibitors
Ramipril
Perindopril
Enalapril
What happens to most ACE inhibitors
They are mostly eliminated by the kidneys
Adverse effects of ACE inhibitors
- hypotension
- dry cough
- angioedem (rare)
- risk of hyperkaliemia (due to the increased absorption of Na/Water and secretion of K)
What are the 3 Ang II Receptor Blockers
- Losartan
- Irbesartan
- Valsartan
How do Ang II receptor blockers work
Block AngII receptors directly
What are the 3 Beta Blockers
- Metoprolol
- Atenolol
- Bisoprolol
Physiological Reactions to Beta Blockers
- Reduce heart rate
- reduced force of contraction
- Decreased release of renin
What are the 3 Calcium Channel Blockers
- Amlodipine
- Nifedipine
- Diltaizem
Physiological reactions to Calcium Channel Blockers
Blocks Ca entry into smooth muscles which leads to vasodilation
some can also reduce heart rate and force of contraction
Adverse Effects of diuretics
- Hypotensive effect
- Reduce peripheral/pulmonary oedema
- Almost all of them are natriuretics
When are diuretics used
In the treatment of hypertension and to relieve the symptoms of congestive heart failure
What are the classes of diuretics
- Osmotic
- Carbonic Anhydrase Inhibitors
- Loop Diuretics
- Thiazide Diuretics
- Potassium - Sparing Diuretics
Loop Diurectics
Furosemide
- Block Na/K/2Cl transporter
- Act on the ascending imbibe of the nephron
- Rapid onset with intense effect
Loop Diuretics Adverse Effects
- Volume depletion
- Hypotension
- Hypo K, Mg, Ca
- Increased uric acid and plasma lipids
- ototoxicity
Thiazide / Thiazide Like diuretics
Hydrochlorothiazide and Chlorthalidone
- Block Na/Cl co transporter
- Act on the distal convoluted tubule
- Prolonged duration of action - moderate intensity
- Less excretion of Ca (which is useful in the tx of kidney stones)
Adverse Effects of Thiazide Diuretics
- hypo Na/K
- Increased plasma uric acid, glucose and lipids
Potassium Sparing Diuretics
Spironolactone and Eplerenone
- Block the effect of aldosterone
- Onset of action is 24-48 hours
- Act on the distal convoluted tubule
- Decrease the excretion of potassium
Potassium Sparing Diuretics Adverse Effects
- Hyperkalemia
- Gyneconastia
- menstrual irregularities
- decreased libido
