Antihypertensive drugs Flashcards
What kind of blood pressure does this patient have?
normal
What type of blood pressure does this patient have?
high systolic blood pressure - these patients have more coronary events even though our vasculature should be able to stand this pressure - this is especially dangerous in elderly patients
What type of blood pressure is this?
white coat syndrome - peaks when they turn on the cuff and peaks when they’re in the office again -
if we follow up patients with white coat syndrome, they often have more risk of coronary events - b/c there may be other simple things that make them this anxious
What does this patient have?
they have super high blood pressure -
how do you assess hypertension?
- confirm BP elevated
- consider investigations for secondary hypertension - like endocrine hypertension or renal hypertension -
- assess life-style factors which increase BP = salt, calories, alcohol, exercise
- does the patient have additional risk factors for CV events?
- Does the patient have target organ damage - ischaemic heart disease, cerebrovascular disease, asymptomatic congential heart defects, or left ventricular hypertrophy
what are some lifestyle mechanisms to lower high blood pressure?
nutrition/diet- reduce weight
reduce salt intake
increase fruit and vegetable intake
reduce excessive alcohol intake
increase physical exercise
smoking cessation -
what kind of general drug therapy can we use to treat high blood pressure?
–Anti-hypertensive drugs
–Other vascular protective agents as appropriate
- Lipid lowering agents - Statins
- Hypoglycaemics
- Anti-thrombotics
- Anti-obesity agents
What kind of antihypertensive Drugs can we use?
ACE-Inhibitors/Angiotensin 2 antagonists
Beta Blockers
Calcium -channel blockers
Diuretics
(ABCD)
what are the three major determinants of blood pressure?
- Blood volume - renin/angiotensin system
- cardiac output - CO is related to heart rate and stroke volume (regulated by cardiac beta 1 adrenoreceptors
- peripheral resistance - the resistance of the arteries is related to the blood vessel compliance. When peripheral resistance increases, the overal compliance decreases and thus the arterial blood pressure increases (regulated by vascular alpha adrenoreceptors)
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Describe the different classifications of adrenergic receptors and their functions
how do alpha-adrenoceptor agonists and antagonists/Blockers work?
alpha 2 agonists cause a fall in blood pressure by inhibition of noradrenaline release -
- Because arteriolar and venous tone are determined by α1-receptors in vascular smooth muscle, α1-antagonists cause a lowering of peripheral resistance (vasodilation) and a fall in blood pressure
- Selective a1-antagonists (e.g. doxazosin or Prazosin) are used in treating hypertension.
–Little effect on cardiac function
–Postural hypotension and impotence are unwanted effects.
how do beta adrenoceptor antagonists work?
work by blocking the effects of the hormone epinephrine, also known as adrenaline. When you take beta blockers, your heart beats more slowly and with less force, thereby reducing blood pressure.
what are the cardiovascular effects of Beta blockers?
•Cardiovascular effects
– Treatment of angina; chronic heart failure; reduce blood pressure
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•Non vascular applications of β antagonists
–Respiratory effect
- May cause increased airway resistance via β2 receptors
- Note: there is no clinical use for β2-antagonists
Describe the renin-angiotensin aldosterone axis
controls the volume of our blood - we can block the pathway (block ACE) - and therefore control blood pressure
This way we can also inhibit the brreakdown of Bradykinin - allowing it to bind to the BK receptor producing nitric oxide which is a vasodilator
What are the uses of and side effects of ACE inhibitors?
•Uses Hypertension
Cardiac failure
Post-Myocardial Infarct Cardiovascular Protection
Nephro-protection (Renal Impairment & Diabetes Mellitus)
•S.E.s Dry cough
Angioedema
Renal failure in bilateral renal artery stenosis
Hyperkalaemia
how do angiotensin 2 antagonists work? (angiotensin receptor blockers)
- they block the actions of angiotensin 2
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What are the uses of ARBs?
same as ACE inhibitors
What are the important roles for calcium entry? What two ways can calcium enter muscle cells?
Calcium Entry in Muscle Cells is via 2 types of Calcium Channels
– Receptor operated
– Voltage operated
Important Roles for Calcium Entry
– Excitation-contraction coupling in smooth & cardiac muscle cells.
– Diastolic depolarization and rapid depolarisation of pacemaker cells of sinoatrial & atrioventricular nodes.
when do we use Dihydropyridines? When do we use non-dihydropyridines? What type of drug are they?
They are calcium channel blockers
Dihydropyridines: greatest affinity for vascular smooth muscle calcium channels
Non-Dihydropyridines (particularly verapamil): greater affinity for cardiac smooth muscle calcium channels
what is the effect of blocking calcium channels in vascular smooth muscles?
causes vasodilation which is helpful in hypertension, angina and raynauds phenomena
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In what condiition do we block calcium channels in pacemaker cells of the SA and AV nodes (verapamil)
Supraventricular Tachyarrhythmias
What are some side effects of calcium channel blockers ?
what is the mechanism of action of thiazide diuretics?
Inhibition of NaCl reabsorption in early distal tubule of renal nephron
describe the guidelines for initiating antihypertensive therapy
what is a contraindication of thiazide diuretics?
gout
what is a contraindication of beta blockers?
asthma
what is a contraindication of calcium antagonists?
heart failure
What are the contraindications of ACE inhibitors?
Pregnancy
Angioneurotic oedema
Hyperkalaemia
Bilateral renal artery stenosis
what is a contraindication of Angiotensin1 blockers?
Pregnancy
Hyperkalaemia
Bilateral renal artery stenosis
