Treating Hypertension Flashcards
What are the common therapeutic drug classes used to treat hypertension.
Diuretics Calcium channel blockers ACE inhibitors Angiotensin II receptor blocker Beta blockers Direct renin inhibitors α Adrenergic receptor antagonists Centrally acting agents
What diuretics are commonly used to treat hypertension?
- Furosemide
- Bendroflumethiazide
- Indapamide
- Amiloride
- Spironolactone
How do diuretics work?
Act on kidneys to increase excretion of water and Na+
What is the mechanism of how Furosemide works?
Act on thick ascending limb of loop of Henle
• Inhibit reabsorption of Na+, K+ and H2O
• Inhibit Na+/K+/2Cl- pump = INCREASED salt, water and potassium loss.
What are common adverse effects of diuretics?
- Urinary frequency
- Postural hypotension
- Hypokalaemia
- Hyponatraemia
- Hyperuricaemia and Gout (inhibition of urate excretion)
What are potassium sparing diuretics?
Spironolactone
How does Spironolactone work?
- Aldosterone receptor antagonist
- Used in combination ‘weak when used alone’
- Prevent hypokalaemia when used with other diuretics.
- Control Na+ and K+ exchange in the distal tubule.
What are the three classes of calcium channel blockers?
- Phenylalkylamines (verapamil)
- Dihydropyridines (amlodipine, nifedipine)
- Benzothiazepines (diltiazem)
How do calcium channel blockers generally work?
- Block cellular movement of Calcium through L-type Ca2+ channels.
- All bind α1 subunit of the L-type calcium channel but at distinct sites
- Mainly affect heart and vascular smooth muscle.
What effect do calcium channel blockers have on peripheral vessels?
• Vasodilator effect on peripheral vessels reduces AFTERLOAD.
What are other clinical uses of calcium channel blockers such as diltiazem?
Angina: dilate coronary vessels – diltiazem
What are other clinical uses of calcium channel blockers such as verapamil?
Antidysrhythmic: impaired AV conduction and reduced contractility. Reduce heart rate and force of contraction.
What are the adverse effects of calcium channel blockers?
- Headache
- Flushing
- Ankle swelling
- Dizziness
- Hypotension
What are the main ACE inhibitors used?
Ramipril
lisinopril
Perindopril
Through what mechanism do ACE inhibitors work?
• Inhibits ACE → Reduced synthesis of angiotensin II which leads to:
- Vasodilation (Angiotensin2 is a vasoconstrictor)
- ↓ Aldosterone - ↓ Na and H2O retention
- Accumulation of bradykinin (a vasodilator)
What Angiotensin II receptor blockers are used clinically?
Candesartan
Losartan
Valsartan
How do Angiotensin II receptor blockers work?
- Angiotensin II receptor antagonists
* Blocks vasoconstrictor effects thus has a anti-hypertensive effect.
ACe inhibitors prevent conversion of what?
Angiotensin I into Angiotensin II by inhibiting ACE.
What are the adverse effects of ACE inhibitors?
- Postural hypotension / dizziness
- Dry cough
- Angioedema
- NEPHROTOXIC and ⬆K+
- Teratogenic
Teratogenic
Teratogenic drugs: A teratogen is an agent that can disturb the development of the embryo or fetus. Teratogens halt the pregnancy or produce a congenital malformation
What beta blockers are used clinically?
Atenolol
Bisoprolol
Note: Not first line.
Through what mechanism do beta blockers work to treat hypertension?
- Both β1 selective
- Reduces heart rate and force of contraction, thus decreased workload.
- Reduces renal production of renin
- Reduces sympathetic activity
What are the adverse efects of beta blockers?
- Lethargy
- Bradycardia
- Hypotension
- Cold peripheries
- Bronchospasm in asthma
- Impotence
What direct renin inhibitor is used clinically?
Aliskirenin
