Flashcards in (chan) 3. Pharmacology (the second half) Deck (165)
High BP is a risk factor for CHD and stroke.
If BP is left untreated, it may lead to...?
- Endothelial cell damages
- Internal organ damage (kidneys, eyes, nerves)
- Extra strain on the heart
: Left Ventricular Hypertrophy (Pulmonary oedema)
: Congestive Heart Failure (Peripheral oedema)
What are the examples of modifiable Cardiovascular Risk Factors?
- High BP
- High salt intake
- Lack of exercise
What are the types and causes of systemic hypertension?
1. Essential (primary) hypertension
- 90-95%; no apparent cause
2. Secondary hypertension
- endocrine gland disorder
- kidney diseases
- drugs induced
3. White-coat hypertension
What are the stages of systemic hypertension & treatment initiation developed by BHS (British Hypertension Society)?
Stage 1 (lifestyle changes)
: ≥140/90mmHg AND ABPM/HBPM ≥135/85mmHg
Stage 2 (treatment initiated)
: ≥160/100mmHg AND ABPM/HBPM ≥150/95mmHg
Stage 3 (treatment initiated)
BP(Blood Pressure) = __ x __
CO x TPR
CO(Cardiac Output) = __ x __
HR x SV
What are the antihypertensive drugs acting on the RAAS & In the kidney?
- ACE inhibitors (ACEi)
- AT1 receptor blockers (ARB)
- Renin inhibitors
- Aldosterone antagonists
What are the antihypertensive drugs acting on Blood Vessels?
- calcium channel blockers
- potassium channel openers
What are the antihypertensive drugs that target the sympathetic NS?
Acting on peripheral adrenergic receptors
- beta-blockers (heart, kidney)
- a1-adrenoceptor antagonists (blood vessels)
- a2-adrenoceptor agonists
- imidazoline receptor agonist
- ganglion blockers
- adrenergic neuron blockers
What is the function of Renin?
- Cause an increase in blood pressure leading to restoration of perfusion pressure in the kidneys
- Renin activates the renin-angiotensin system by cleaving angiotensinogen, produced by the liver, to yield angiotensin i which is further converted into angiotensin ii by ACE
How is Angiotensin II formed and what is its effect?
Angiotensin I is produced by the action of renin (an enzyme produced by the kidneys) on a protein called angiotensinogen, which is formed by the liver.
Angiotensin I is transformed into angiotensin II in the blood by the action of angiotensin-converting enzyme (ACE).
Angiotensin II acts directly on blood vessels, causing their constriction and thereby raising blood pressure.
How does ACEi work?
Angiotensin converting enzyme inhibitors (ACE inhibitors) are medications that slow (inhibit) the activity of the enzyme ACE, which decreases the production of angiotensin II.
As a result, blood vessels enlarge or dilate, and blood pressure is reduced.
ACEi are often used together with diuretics.
Which adverse effects could the combination of an ACEi with a diuretic and an NSAID have?
- dangerously reduced GFR and renal failure (triple whammy)
What are the adverse effects of ACEi?
- Taste disturbance
- Dry cough
- Reversible renal failure in patients
Drugs that act on the RAAS are not the first choice of therapy in some patients. Who are they?
- Elderly (over 55 yrs old)
- Patients of African or Caribbean family origin (Due to low activity of RAAS)
What is the Calcium Channel Blocker's mechanism of antihypertensive action and its systemic effect?
- Block of the L-type Voltage-Activated calcium influx in vascular smooth muscle cells
- Arterial Dilation (decrease in TPR & Cardiac afterload)
Which patients is Calcium Channel Blocker (CCB) preferred first-line treatment in?
- Elderly (over 55 yrs old)
- Patients of African-American or Caribbean family origin of any age
- Severe hypertension in pregnancy
What are the common adverse effects of CCBs?
- Postural hypotension
- Ankle oedema
- Headache & Flushes
- Myocardial ischaemia
What is the Potassium Channel Activator's mechanism of action?
- Activation of ATP-sensitive potassium channels in vascular smooth muscle
- Inducing Membrane hyperpolarisation
- Closure of L-type VACCs
- Reduced Calcium influx
What are the adverse effects of Potassium channel activators?
- Reflex tachycardia
- Fluid retention
- Diabetes mellites
What is Hydralazine's systemic effects and mechanismo of action?
- Dilation of arteries and arterioles, decrease in TPR & cardiac afterload
- MoA not clear
What are the antihypertensive drugs that act on the sympathetic NS?
- ß-BLOCKERS (-olol)
- α1 –ADRENOCEPTOR ANTAGONISTS
What is the mechanism of ß-BLOCKERS and its benefit as hypertensive therapy?
- Block ß1 receptors in the heart
- Reduces reflex tachycardia
- Reduces renin release and activation of the RAAS
- Reduces central sympathetic activity
What are the adverse effects of ß-BLOCKERS?
- Erectile dysfunction
What is the machanism of α1-Adrenoceptor antagonists and its systemic effect?
- Inhibition of postsynaptic α1-adrenoceptors on vascular smooth muscle cells
- Arterial dilation: reduced TPR and cardiac afterload
- Venodilation: reduced cardiac preload and SV
Adverse effects of α1-Adrenoceptor antagonist?
- First-dose hypotension
what is the mechanism of action of central-acting drugs as antihypertensives?
- Reduction in the activity of vasomotor centre in the brain, leading to decrease in sympathetic activity and increase in parasympathetic outflow
How does Ganglion Blocking Drugs (antihypertensives on sympathetic NS) work?
- Competitive nicotinic acetylcholine receptor antagonist at the autonomic ganglia
- progressive disease of large and medium-sized muscular arteries characterised by inflammation and dysfunction of the lining of the involved blood vessels and the build up of cholesterol, lipids and cellular debris
- this results in formation of a plaque, obstruction of blood flow and diminished oxygen supply to target organs