Antihypertensives Flashcards
What is the first-line agent in managing hypertension?
In
White 45 year old?
Black 45 year old?
White 66 year old?
Black 66 year old?
68 year old with diabetes?
If white, under 55 or Diabetes - ACEi or ARB (first ACEi, if ACEi not tolerated ARB)
If aftro-carribean or >55 without T2DM: CCB
White 45 year old? - ACEi or ARB
Black 45 year old? - CCB
White 66 year old? - CCB
Black 66 year old? - CCB
68 year old with diabetes? - ACEI or ARB
What is the 2nd line treatment for hypertension in people >55 or Afro-Carribeans who cannot tolerate first line?
CCB is first line
If not toerated:
Thiazide diuretic
What thiazide/ thiazide like diuretic should be used in treatment for hypertension?
If starting new: thiazide-like diuretic preferred (e.g. indapamide)
If stable on thiazide diuretic: continue treattment (e.g. bendroflumethiazide, hydrochlorothiazide)
What is step 2 treatment of hypertension a patient who is not controlled on a ACEi or ARB?
Add a CCB or thiazide-like diuretic
What is step 2 treatment of hypertension a patient who is not controlled on a CCB?
ACEi or ARB or thiazide-like diuretic
(ARB preferred in non-diabetic afro-carribeans)
What is step 3 in antihypertensive treatment in adults in the Uk?
Combinatiton of
1. CCB
2. ACEi/ARB
3. Thiazide-like diuretic
What is classified as treatment resistanc hypertension?
If not controlled on Step 3 of hypertension treatment (ARB/ACEi+CCB+Thiazide-like diuretic)
What is the target BP for someone on antihypertensives?
Name 3 ACEi
Ramipril
lisinopril
Captopril etc.
What is the Mechanism of Action of ACE inhibitors?
Stop conversion of ACE and terefore converstion of Angiotensinogen I to Angiotensin II
Therefore
1. Loss of Angiotensin II mediated Vasoconstriction –> Vasodilation
2. Reduced release of aldosterone –> Less Water and Sodium retention in distal tubule
What is the effect of Aldosterone in the kidney?
Binds to intracellular mineralcorticoid receptors on distal tubule and collecting duct
- Sodium and Water retention
- Potassium excretion
- (H+ resorption)
Therefore
Increase Sodium, BP and acidosis with potassium loss
What are the most common side-effets of ACEi?
- chronic dry cough (4-35%)
- (orthostatic) hypotension
- Headache, diarrhoea, rash, vomiting
What are rare but serious side-effect for prescribing ACE inhibitors?
Wha should be done to minimise the risk?
- Renal impairment and hyperkalaemia (renal function check before initiation and 1-2 weeks after commencement and dose change)
- Hepato-biliary disorders - stop when signs of jaundice or LFT derrangement
- Angio-oedema: stop and avoid ARB aswell
Name 2 Examples of Angiotensin-II receptor blockers
Losartan
Valsartan
Candestartan
What are normal starting dosages for therapy with Candesartan or Losartan?
- Candesartan 8mg OD (Maximum 32 OD)
- Losartan 50mg OD (Maximum 100mg OD)
What are common starting dosages of Ramipril and Lisinopril?
Ramipril 1.25-2.5mg OD (Max 10mg OD)
Lisinopril 10mg OD (Max 80mg OD)
What are the most important side-effects of ARBs?
The same as ACEi
- chronic dry cough (4-35%)
- (orthostatic) hypotension
- Headache, diarrhoea, rash, vomiting
- Hyperkalaemia and renal impairment (check on commencement)
- Angio-oedema
What differnet Classes of Calcium-Channel Blockers are there?
How do they differ?
Two main classes
- Dihydropyridines (e.g. Nifedipine (short-acting) , Amlodipine (long-acting)) - Strong Vasodilation with minimal myocardial depressant activity - non-rate limiting
- Nondihydropyridines (Diltiazem, Verapamil) - Moderate vasodilators but strong myocardial depressants (therefore can be used in SVT, AF) - rate limiting
Why should CCB be used carefully in patients with heart failure or angina?
Because of potential hypotension and reflex tachycardia –> worsening of cardiac ischaemia due to increased myocardial oxygen demand
What is the Mechanism of Action of CCB (Dihydropyridinnes) in the treatment of hypertension?
Bind to L-type calcium chanel on vascular smooth muscle cells –> less opening of Ca2+ influx
–> Vascular smooth muscle relaxation –> Vasodilation
Name 2 Calcium Chanel-Blockers regularly used for treament of Hypertension
Amlodipine
Nifedipine
What are some conraindications for the pescribing of Calcium-Chanel blockers?
- Heart failure (can prescipitate HF) - Amlodpipine may be used cautiosly in stable HF
- Hepatic and renal impairment
- For rate-limiting: AV block, unstabel angina or MI
What are the most common side-effects of Amlodipine?
- Headaches
- Dizziness
- Flushing
- Palpitations
- Peripheral oedema
What is the preferred agent (thiazide-like or thiazide diuretic) used in the treatmen of hypertension?
Name 2 others
Indapamide (Thiazide-like diuretic)
Other Thiazide diuretics: bendroflumethiazide, hydrochlorothiazide
What is the mechanism of Action of Thiazide diuretics?
Inhibition of Na+-Cl- cotransporters in the early distal convoluted tubule → ↑ excretion of Na+ (saluresis) and Cl- → ↓ diluting capacity of nephron and ↑ excretion of potassium (kaliuresis) and ↓ excretion of calcium → diuresis
What are the main biochemical side-effects of thiazide diuretics?
- Hypokalaemia (+metabolic alkalosis)
- Hyponatraemia
HyperGLUC
Hyper Glycaemia
Hyper Lipidaemia
Hyper Uricaemia
Hyper Calcaemia
What are the main side-effects of thiazide diuretics?
- Postural hypotension
- Biochemical disturbances esp. hyperglycaemia and hypokalaemia
List 4 contraindications to the administration of beta-blockers
- in combination with verapamil or diltiazem (risk of heart block)
- with bradycardia (heart rate less than 50 beats per minute), type II heart block or complete heart block (risk of complete heart block, asystole)
- in diabetes mellitus patients with frequent hypoglycaemic episodes (risk of suppressing hypoglycaemic symptoms)
- if prescribed a non-selective beta-blocker (including topical beta-blockers) in a history of asthma requiring treatment (risk of increased bronchospasm)
