Cardiac pharmacology and hypertension Flashcards
What is high BP a major risk factor for?
Stroke – ischaemic and haemorrhagic
Myocardial infarction
Heart failure
Chronic renal disease
Cognitive decline
Premature death
Increases the risk of: Atrial fibrillation (independent stroke risk)
Each 2 mmHg rise in systolic BP is associated with:
7% increased mortality from ischaemic heart disease
10% increased mortality from stroke
Continuous risk with increases in BP
When do you have suspected hypertension?
Clinic BP 140/90 mmHg or higher
How are people with suspected hypertension confirmed to have hypertension?
ambulatory blood pressure monitoring (ABPM)
Stage 1 hypertension features?
140/90 Clinic BP
135/85 Ambulatory/Home readings
Stage 2 hypertension features?
160/100 Clinic BP
150/95 Ambulatory/Home readings
Severe hypertension features
Systolic BP 180/120
Diastolic PB 110
What are the treatments for primary hypertension?
Lifestyle modification
Antihypertensive drug therapy
Who do we offer antihypertensive drug treatment too?
people aged under 80 years with stage 1 hypertension who have one or more of the following:
- Target organ damage
- Established cardiovascular disease
- Renal disease
- Diabetes
- A 10-year cardiovascular risk of 20% or greater.
Offer antihypertensive drug treatment to people of any age with stage 2 hypertension.
What do we target for therapy in BP control?
Cardiac output and Peripheral Resistance
Interplay between:
a. Renin-Angiotensin-Aldosterone system
b. Sympathetic nervous system (noradrenaline)
Local vascular vasoconstrictor and vasodilator mediators
What is the most potent vasoconstrictor and main reason for increase in BP?
Angiotensin 2
What does angiotensin 2 do?
1.Vascular Growth:
Hyperplasia
Hypertrophy
Salt retention
1. Aldosterone release
2. Tubular sodium reabsorption- kidney
3. Increase peripheral resistance and Cardiac output
4. act on sympathetic nerve ends to cause noradrenaline release
What does noradrenaline do?
Part of symapthetic ns
Increased renin production
Increases peripheral resistance and CO
What do ACE inhibitors do?
Block ACE, conversion from angiotensin 1 to angiotensin 2
Decrease BP
What do ARB’s do? (Angiotensin receptor blockers)
Block angiotensin 2 on their receptors decreasing CO and PR
Block angiotensin 2 at receptor level
End in sartan
All very similar drugs
Widely used
What do calcium channel blockers do?
Act on PR receptors
What do beta blockers do?
block beta adrenoreceptors – have effect on cardiac output
When are ACE inhibitors used?
Hypertension
Heart failure
Diabetic nephropathy
Examples of ACE inhibitors?
RAMIPRIL
PERINDOPRIL
ENALAPRIL
TRANDOLAPRIL
Side effects of Ace inhibitors?
- Related to reduced angiotensin II formation
a. Hypotension
b. Acute renal failure
c. Hyperkalaemia
d. Teratogenic effects in pregnancy - Related to increased kinin production
a. Cough
b. Rash
c. Anaphylactoid reactions
Main clinical indications for ARBs?
Hypertension
Diabetic nephropathy
Heart failure (when ACE-I contraindicated)
Examples of ARBs?
CANDESARTAN
VALSARTAN
TELMISARTAN
LOSARTAN
IRBESARTAN
Main side effects of ARBs?
Symptomatic hypotension (especially volume deplete patients)
Hyperkalaemia
Potential for renal dysfunction
Rash
Angio-oedema
Contraindicated in pregnancy
Generally very well tolerated
Main clinical indications of calcium channel blockers?
Hypertension
Ischaemic heart disease (IHD) – angina
Arrhythmia (tachycardia)
Examples of calcium channel blockers?
AMLODIPINE
NIFEDIPINE
DILTIAZEM
FELODIPINE
LACIDIPINE
VERAPAMIL
CCB: Dihydropyridines
nifedipine, amlodipine, felodipine, lacidipine
affect vascular smooth muscle
Peripheral arterial vasodilators
CCB: Phenylalkylamines
verapamil
Main effects on the heart
Negatively chronotropic, negatively inotropic
CCB: Benzothiazepines
diltiazem
peripheral vascular effects
Side effects of CCB: Dihydropyridines
Due to peripheral vasodilatation (mainly dihydropyridines)
Flushing
Headache
Oedema
Palpitations
Side effects of verapamil
Due to negatively chronotropic effects (mainly verapamil/diltiazem)
Bradycardia
Atrioventricular block
Due to negatively inotropic effects (mainly verapamil)
Worsening of cardiac failure
Verapamil causes constipation
Main clinical indications of beta adrenoreceptor blockers?
Ischaemic heart disease (IHD) – angina
Heart failure
Arrhythmia
Hypertension