Treatment of Hypertension Flashcards
What are some factors which make it such that hypertension is not treated as often as it should ?
- Lack of symptoms/Unaware (potentially millions of people in UK undiagnosed)
- poor health literacy
- poor concordance (adherence)
What are the factors which influence the probability of harm due to hypertension ?
- How high blood pressure is
- How long the person has had high BP
- Whether any relevant concurrent health problems (such as high cholesterol or diabetes)
- Concordance with meds / lifestyle changes.
What is a problem if hypertension goes untreated for a while ?
Can lead to vascular and renal changes leading to treatment-resistant state.
Which demographic groups does CVS disease affect more, in Scotland ?
Both incidence and prevalence of CVD are higher amongst men, the elderly and in deprived areas of Scotland.
What proportion of the Scottish population over the age of 16 had a CV disease ? What proportion of all deaths in Scotland is CV disease responsible for ?
15%
Cardiovascular disease caused more than a quarter of all deaths in Scotland in 2015.”
What are the goals of hypertension treatment ?
- Reduce arterial blood pressure to recommended targets
- Reduce risk of end organ damage (cardiovascular, renal, cerebrovascular)
- Reduce risk of mortality due to Cardiovascular disease
What do ABPM and HBPM stand for ?
ABPM: ambulatory blood pressure monitoring
HBPM: home blood pressure monitoring
When are anti-hypertensive drugs indicated?
- People of any age with stage 2 or 3 hypertension
- People with stage 1 hypertension who have one or more of the following:
• target organ damage
• established cardiovascular disease (CHD,CVA)
• renal disease
• diabetes
• a 10-year cardiovascular risk equivalent to 20% or greater.
How may CV risk be calculated ?
Based on: • BP • Age • Weight/Height • Gender • Smoking • cholesterol • Ethnicity • Social class • Family history • Diabetes, rheumatoid arthritis, renal function
Identify tools which allow the calculation of CV risk.
- ASSIGN
- Qrisk
- JBS3
What are the BP targets that we usually want to achieve in hypertension treatment ?
STANDARD PATIENTS: <140 / 90 mmHg
OVER 80 YEAR OLD: <150 / 90 mmHg
CARDIAC/RENAL DISEASE/DIABETES: <130 / 80 mmHg
But also individualise targets based on appropriateness, tolerability and frailty (patient centered!).
Why is it important to review the patient’s current drugs before commencing hypertension treatment ?
Because increase in BP are possible with:
• NSAIDS (e.g. Ibuprofen, diclofenac)
• Oral steroids (e.g. Prednisolone)
• Venlafaxine anti-depressant)
• Oral sympathomimetic decongestants (e.g. Pseudoephedrine – “Sudafed”)
• Soluble or dispersible drugs
• Illicit drug use
Identify all the main drug classes used in hypertension treatment.
- Renin-Angiotensin system inhibitors (ACE inhibitors and Angiotensin AT1 receptor blockers/ARBs)
- Calcium channel blockers
- Diuretics (Thiazide-like diuretics and high dose loop diuretics)
Give examples of drugs in each main drug class.
RENIN ANGIOTENSIN SYSTEM INHIBITORS 1) ACE Inhibitors • Ramipril, lisinopril, captopril 2) ARBs • Losartan, candesartan, irbesartan
CALCIUM CHANNEL BLOCKERS
1) Dihydropyridine-like CCBs
• Amlodipine, felodipine, lercanidipine
DIURETICS 1) Thiazide-like diuretics • Indapamide, bendroflumethiazide 2) High dose loop diuretics • Furosemide
What is the problem with using certain diuretics for hypertension treatment ?
- Thiazide-like diuretics – often essential at step 2 or 3, but not effective in moderate to severe renal impairment
- High dose loop diuretics may be used instead for raised BP in renal failure
What are the treatments for resistant hypertension ? Mention how they work.
SNS ANTAGONISTS 1) Beta Blockers • atenolol, bisoprolol 2) a1 Adrenoreceptor Blockers (block vasoconstriction, resulting in vasodilatation) • doxazosin
KIDNEY FUNCTION MODIFIERS 1) Potassium Sparing Diuretics • amiloride 2) Aldosterone Antagonists • spironolactone
What is the shortcoming of beta blockers in terms of hypertension treatment ?
Beta blockers are less effective at reducing cardiac events and stroke
Explain how ACE inhibitors, and ARBs work (both renin-angiotensin system inhibitors)
ACE Inhibitors
Inhibit the ACE enzyme, which catalyses the conversion of Angiotensin I into Angiotensin II
ARBs
Prevent binding of Angiotensin II with AT1 receptors
Normally, Angiotensin I → Angiotensin → AT1 receptor → Vascular growth (hyperplasia and hypertrophy) + Vasoconstriction (directly, and via increased NA release from sympathetic nerves) + Salt retention (via aldosterone secretion and tubular Na+ reabsorption)
Hence, ACE Inhibitors and ARBs reduce vascular growth, salt retention, and vasoconstriction.
Explain how Calcium channel blockers work.
• In general, block entry of calcium through slow channels in cardiac and smooth muscle
Particularly, in hypertension, we use Dihydropyridine-like CCBs (e.g. amlodipine, felodipine, lercanidipine) :
• greater impact on vascular smooth muscle, reduces PR, less effect on myocardium
Explain how Kidney function modifiers work.
Diuretics in general, block reabsorption of sodium (i.e. increase exretion of sodium and water). E.g.
1) Thiazide-like diuretics
Inhibit Na+Cl- co-transporter in distal tubule
Also cause vasodilation
2) High dose loop diuretics
Inhibits Sodium Potassium Chloride (K+, Na+ and 2Cl- out) co-transporter in thick ascending loop
Do not have same effect as thiazide-like diuretics on vascular smooth muscle
3) Aldosterone antagonists (e.g. spironolactone)
“Bind to receptor in the collecting tubule to prevent aldosterone binding (inhibit Na+Cl- pump)
All of these inhibit sodium reabsorption in nephron, which results in reduced sodium and water retention (in the blood), Increased diuresis, decreased blood volume and decreased BP
How do beta blockers work in addressing hypertension ?
Block the effects of adrenaline, resulting in reduced HR and force of contraction
How do a1 adrenoreceptor blockers work in addressing hypertension ?
They block noraderenaline binding to a1 adrenoreceptors, which prevents blood vessels from contracting.
Identify the common side effects of ACE inhibitors.
• Persistent dry cough (15%, due to ACE inhibitors releasing bradykinin)
• Slight increased risk of angioedema (particularly in patients with African/Caribbean ethnicity, so would use ARBs for that group)
(effect possibly also due to release of bradykinin)
• Tiredness
• Dizziness, headaches
• Risk of hyperkalaemia (care with drug interactions)
• Renal impairment - monitor (though can be reno-protective also)
• Avoid in bilateral renal artery stenosis
• teratogenic (so avoid in pregnant women, use beta blockers in young women of child beating age)
Identify the common side effects of ARBs.
- Back/leg pain
- Dizziness, headaches
- Risk of hyperkalaemia
- Renal impairment
- Avoid in bilat renal artery stenosis
- teratogenic
Identify the common side effects of Dihydropyridine like calcium channel blockers.
• Dizziness, headaches, flushing, ankle oedema (due to vasodilation in peripheries. Can be long-standing, so can be reason to withdraw that treatment unlike the other side effects)
Identify the common side effects of Thiazide-like diuretics.
- Hypokalemia, hyponatraemia, gout, impotence
- Monitor for dehydration
- Ineffective in moderate to severe renal impairment (GFR<30mls/min)
Identify the common side effects of Aldosterone antagonist diuretics.
- Hyperkalaemia
- Renal impairment
- GI upset
- Spironolactone - oestrogen (spironolactone has effects on receptors in other parts of body) related side-effects such a menstrual irregularities, testicular atrophy
What are the pros and cons of multi-drug treatment of hypertension ?
PROS
• Reduced mortality/morbidity
• Each drug class working at different sites on body – can achieve BP treatment targets more quickly
• Reduces dose burden of individual drugs thereby minimising side-effects
CONS
• Concordance problem (“The aim of concordance is the establishment of a therapeutic alliance between the clinician and patient”)
“I felt fine before I started these drugs!”
“I keep forgetting to take all these drugs”
- Side-effects may be more frequent
- Increased drug costs to NHS
