Drugs + Hypertension Flashcards
What is the limit for hypertension suspicion
140/90 mmHg or higher
How do we confirm hypertension diagnosis
ABPM and HBPM
How do we use ABPM
Aka two measurements an hour during person’s usual waking hours, average of 14 measurements to confirm
How do we use HBPM
- Two consecutive seated measurements 1 minute apart
- BP is recorded twice a day for at least 4 days - 1 week
- Measurements on first dy discarded and average value of all remaining is used
What three-drug combination is used to treat hypertension
ACE
Calcium-channel blocker
Thiazide-like diuretic
What do we treat people aged under 55 with for hypertension
ACE
What do we treat people aged over 55, black of any age with for hypertension
Calcium-channel blocker
What is step 2 treatment of hypertension
ACE
Calcium-channel blocker
What is step 3 treatment
ACE
Calcium-ion channel blockers
Thiazide-like diuretic
What is step 4 hypertension
Resistant hypertension
How is resistant hypertension treated
ACE, Calcium, Thiazide and beta-blockers
Describe the RAAS system
- When renal blood flow is reduced, juxtaglomerular cells convert prorenin -> renin
- Renin converts angiotensinogen -> angiotensin I
- Angiotensin I converted to angiotensin II by ACE in lungs
- Angiotensin II stimulates secretion of aldosterone and causes vasoconstriction
Name the renin inhibitor drug
Aliskiren
How do beta-blockers effect RAAS
Prevent renin activation
What drug inhibits the angiotensin receptors
AT1 antagonists - ARB
What do all ACE inhibitor drugs end in
- pril
e. g. Captopril, Cilanzapril
What effects to ACE Inhibitors have on the body
- Reduced vascular resistance due to:
Decreased smooth muscle tone
Neuronal NE release decreased
CNS sympathetic tone decreased - ECF volume reduced as less aldosterone and reabsorption of Na
- Bradykinin elevated No, PGI2 not involved
Advantages of using ACE inhibitors
- No effect on neutral lipids (caused by diuretics)
- No effect on insulin (b-blockers and diuretics)
- No Heart failure
- No peripheral vascular disease effect
- Increase QOL
Role of bradykinin
Compound that causes contraction of smooth muscles and dilation of blood vessels
What are three unwanted effects of ACE inhibitors
- Bradykinin-mediated
- Persistent dry cough
- Angioedema - Lack of angiotensin can result in renal artery stenosis -> renal failure
- Lack of aldosterone can result in hyperkalaemia
What suffix do all Angiotensin Receptor Blockers have
-sartan
Candesartan
Eposartan
Unwanted side-effects of ARBs
- Renal Artery Stenosis
- Hyperkalaemia
No bradykinin-mediated effects
How do Calcium Channel Blockers function
Do not inhibit calcium but prevent opening of voltage-gates calcium channels.
How many groups of Calcium Channel Blockers are there
3
Name the three groups of Calcium Channel Blockers
- Dihydropyridines
- Phenylalkylamines (Verapamil and Diltiazem)
- Diphenylalkylamines
What do all dihydropyridines end in
-dipine
E.g. Nifedipine Nicardipine Isradipine Lacidipine Lercadipine Amlodipine Nimodipine
How do nifedipine function
Reflex tachycardia
Advantages of Amlodipine
No effect on heart failure
Longer duration of action once daily doses
When is nimodipine given
Targets cerebral arteries
When is Verapamil given
Arrhythmias
Hypertension
Angina
When should Verapamil be avoided
If patient is being given B-blockers
When is Dilitiazem given
Angina
Hypertension
How does Verapamil effect DHP receptors
Inhibits binding (via allosteric site)
How does Dilitiazem effect DHP receptors
Enhances them
What metabolite of heart disease binds to DHP
Palmitoyl Carnitine
How does amlodipine function
Peripheral vasodilator
When is amlodipine given
Mild hypertension
To who is amlodipine given
55+ and afro/caribbean
When should amlodipine be avoided
Heart failure
Suffix of all Thiazide diuretics
-thialide
Formula for BP
CO x TPR
What diastolic range is considered mild hypertension
90-109 mmHg
How does a low BP effect hypertension
Means BP does not increase with age
What are Dahl Rat genes
Strains are sensitive and resistant to development on high salt diet
How can salt resistance by kidneys be solved
Renal transplant
What part of the kidney is effected by high salt diets
NaK2Cl transporters
What transporters do thiazides bind to
Na/Cl co-transporters in DCT
How do thiazides effect Na/K/2Cl pumps
No effect
What compound becomes an additive with thiazide
Frusemide
What substance inhibits thiazide binding
Cl
What substance stimulates thiazide binding
Na
How do thiazides effect urine production
Increased by 2l over first three days
Why is the diuretic effect of thiazides not sustained
RAAS is eventually activated
How and why does thiazides effect BP
Initial BP fall due to decreased CO, decreased TPR and CO returns to normal
How do diuretics effect Na/Ca exchange
Decreases it
How do diuretics effect blood vessel walls
- Decreased Na/water content
- Decreased wall thickness
- Increased lumens diameter
Is diuretic effect on decreased TPR mainly direct or indirect
Indirect
Effect of thiazides on vasodilators
Inhibits vasoconstriction by Ang II, NE
How do thiazides effect cGP phosphodiesterase
Inhibits them
The action of which two molecules are potentiated by Thiazides
ANP and NO
How do Thiazides effect K-channels
Opens them
In what three cases are thiazides used for
- Monotherapy hypertension
- Oedema
- Diabetes Insipidus
What advantages does Thiazides have in dealing with hypertension over amlodipine
- Advantage if heart failure present
2. Counterindicates Beta-blockers
6 Side-Effects of thiazides
- Volume depletion
- Hypokalaemia (fixed with K supplements/K sparing diuretics
- Pre-existing gout worsens
- Decreased calcium excretion
- Inhibits insulin release in diabetes
- Increased lipid levels
Name three non-thiazide inhibitors
- Chlorthalidone
- Mefruside
- Indapamide
Function of mefruside
Inhibits Na/K/2Cl
Function of Indapamide
Stronger vasodilator
What drug should be given to people with resistant hypertension
Spironolactone if hypokalaemic
Thiazide if hyperkalaemic
Where are alpha-1 adrenoceptors found
Vascular smooth muscle (vasoconstrictor)
Role of the alpha adrenoceptor antagonists tamsulosin
Selective for bladder, relaxes prostate to inhibit hypertrophy
Name two alpha-adrenoceptor antagonists
Doxazosin
Indoramin
When are beta-blockers given
- Angina
- Heart Failure
- Hypertension
- Arrhythmia
Atenolol function vs Propranolol
Atenolol is selective for beta-1 receptors
How does Propranolol effect the CNS
Crosses BBB
How do beta-blockers effect Kidneys
Decreased renin secretion via beta-1
How do beta-blockers effect blood vessels
Enhances NE release on beta-2
Adverse effect of beta-blockers binding to B-1
Bradycardia
Adverse effects of beta-blockers on beta-2
- Bronchoconstriction
- Peripheral Vasoconstriction
- Hypoglycaemia
Side-effect of verapamil
Constipation
Side-effect of most calcium-ion blockers
Dihydropyrodines
- Headache
- Palpitations
Phenyl amines
3. Bradycardia
Diphenylalkylamines
Cardiac failure worsening