Hypertension Flashcards
What are the 4 types of drugs that can be prescribed for hypertension?
- Angiotensin converting enzyme inhibitors
- Calcium channel blockers
- Thiazide or thiazide-like diuretics
- Angiotensin receptor blockers
Name 3 ACE inhibitors.
Ramipril
Lisinopril
Perindopril
What is the primary mechanism of action of ACE inhibitors?
Inhibit the angiotensin converting enzyme (ACE).
This prevents the conversion of angiotensin I to angiotensin II by ACE.
What do ACE inhibitors target?
Angiotensin converting enzyme (found in high conc in lungs)
What are the main side effects of ACE inhibitors?
- Cough
- Hypotension
- Hyperkalaemia (care with K+ supplements or K+-sparing diuretics)
- Foetal Injury (AVOID IN PREGNANT WOMEN)
- Renal failure (in patients with renal artery stenosis)-
- Urticaria/Angioedema
Most ACE inhibitors (except lisinopril) are pro-drugs. Where are they metabolised /activated?
Liver
What needs to be constantly monitored in patients being treated with ACE inhibitors?
- eGFR
- serum Potassium
Why does serum potassium need to be monitored?
- ACE inhibitors will reduce Ang II.
- This will cause a reduction in Aldosterone.
- Less Potassium will be excreted and more will remain in plasma -> hyperkalaemia.
Why do ACE inhibitors cause coughs?
- Ang II usually stimulates the breakdown of bradykinin in the lungs. Bradykinin is responsible for causing the cough reflex.
- ACE inhibitors reduce Ang II so there is bradykinin accumulates and causes coughing.
Drugs ending in -dipine are likely to be….
Calcium channel blockers
Name some calcium ion channel blockers.
Amlodipine
Felodipine
Describe the mechanism of action of calcium channel blockers.
- Block L-type calcium channels – predominantly on arteriolar vascular smooth muscle.
- This results in a decrease in calcium influx, with downstream inhibition of myosin light chain kinase and prevention of cross-bridge formation.
- The resultant vasodilation reduces peripheral resistance.
What is the target of calcium channel blockers?
L-type calcium channels on arteriolar smooth muscle cells
What are the side effects of using calcium channel blockers?
Ankle oedema
Constipation
Palpitations
Flushing/Headaches
What are the 2 types of calcium channel blockers?
- Dihydropyridines
- non-dihydropyridines