Hypertension, Hypotension and Therapeutic Intervention Flashcards
(33 cards)
Define hypertension.
> = 140mmHg systolic pressure or >= 90mmHg diastolic pressure.
What is the equation for arterial blood pressure?
ABP = CO * TPR
List 3 systems that maintain blood pressure.
1 - Baroreceptor reflex.
2 - Autonomic nervous system.
3 - Renin-angiotensin-aldosterone system.
List 3 factors that determine drug choice for hypertension treatment.
1 - Age.
2 - Genetics.
3 - Comorbidities.
List 2 examples of ACE inhibitors.
1 - Lisinopril.
2 - Enalapril.
Describe the mechanism of action of ACE inhibitors.
- Inhibition of ACE decreases angiotensin II, decreasing CO and TPR.
- ACE inhibitors also decrease degradation of vasodilator kinins, e.g. bradykinin.
Give an example of a side effect of ACE inhibitors.
What might cause this side effect?
- Dry cough.
- Due to decreased degradation of kinins in the lungs.
Give an example of a drug that is contraindicated with ACE inhibitors.
Why is this drugs contraindicated with ACE inhibitors?
- Diuretics.
- Causes sudden, severe hypotension if taken with diuretics.
When are ACE inhibitors used clinically for hypertensive patients?
They are the first line treatment for uncomplicated, mild hypertension in younger patients.
List 2 angiotensin II type 1 receptor (AT1 receptor) antagonists.
1 - Losartan.
2 - Irbesartan.
Describe the mechanism of action of angiotensin II type 1 receptor (AT1 receptor) antagonists.
Decreases vasoconstriction by angiotensin II, decreasing CO and TPR.
When are ACE inhibitors used clinically for hypertensive patients?
If ACE inhibitors are not tolerated.
Give an example of a calcium channel blocker.
Amlodipine.
Describe the mechanism of action of calcium channel blockers.
Decreases contractility of vascular muscle, decreasing TPR.
List 2 side effects of calcium channel blockers.
1 - Heart dysrhythmias.
2 - Decreased GIT activity.
When are calcium channel blockers used clinically for hypertensive patients?
They are the first line treatment for uncomplicated, mild hypertension.
Which diuretics are best for treating hypertension?
Thiazide / thiazide-like diuretics (better than loop diuretics).
Describe the mechanism of action of diuretics for treatment of hypertension
Biphasic mechanism:
- Initially, increases water and Na+ excretion from the kidneys, decreasing blood volume and therefore cardiac output.
- In the later phase, cause arterial dilation due to a decrease in intracellular Ca2+, decreasing TPR.
- NB compensation occurs to restore blood volume after initial phase.
Give an example of an unwanted effect of diuretics as a treatment for hypertension.
Hypokalaemia.
When are diuretics used clinically for hypertensive patients?
They are the first line treatment for uncomplicated, mild hypertension.
List 2 beta antagonists.
For each drug, state the subclass of beta antagonists to which they bind.
1 - Propranolol (beta 1 and 2).
2 - Atenolol (beta 1).
Describe the mechanism of action of beta antagonists.
1 - Decreases heart rate and contractility, decreasing cardiac output (beta 1 receptors).
2 - Decrease renin secretion, resulting in decreased blood angiotensin II, reducing CO and TPR.
List 2 side effects of beta antagonists.
1 - Bronchospasm (beta 2 receptors).
2 - Exercise intolerance.
When are beta antagonists used clinically for hypertensive patients?
Recent guidance is to avoid as beta blocker use is associated with development of type 2 diabetes.
