Treatment of Hypertension

Question 1

What are the types of regulation for Blood Pressure?

What is Hypertension?

Outline the 2 types of HT and their causes?

Answer 1

• Short term: using neural systems e.g. baroreceptors
  Long-term: using hormones and Na Balance e.g. ECFV, Vascular tone
• HT is > 140/90 mmHg for <50 yrs, or >160/95 mmHg for those older.
• • Essential/Primary HT: most common with an unknown cause. Genetic pre-disposition, age, ethnicity, and environmental factors can be a cause through many mechanisms, like increased SNS, RAAS, Obesity/insulin resistance, Endothelial dysfunction, VSMC disorders, defect in renal Na handling/increased salt intake.
  • Secondary HT: less common with a known cause – can be due to renal diseases (glomerulonephritis), vascular disorders (renal artery stenosis), hormonal disorders (Conn’s, Cushing’s), drugs, pregnancy, and monogenic genetic diseases (Liddle’s).

Question 2

Why is there motivation to treat Hypertension?

Answer 2

• Only a 5 mmHg drop in diastolic BP for 5 years significantly reduces risk of stroke, MI, and vascular death.
• There are targets of getting the BP <140/90 mmHg, preventing target organ damage, and controlling the other CVS risk factors.

Question 3

What are some of the Lifestyle changes in Hypertension treatment?

Answer 3

Quit smoking, reduce alcohol intake, control weight, eat less salt, regular exercise, behavioural therapies

Question 4

Pharmacological treatment of Hypertension - ACEi and ARBs:

What do they do?

What are some of the side-effects of just ACEi?

What are some of the side effects of both ACEi and ARBs?

Answer 4

• Decrease Vasoconstriction, Aldosterone secretion = ↓BP.
• • ACEi prevent the breakdown of Bradykinin = ↑Bradykinin levels = Cough and Angioedema.
• • Both drugs cause Hyperkalaemia due to less aldosterone action, which leads to ↓Na reabsorption and K excretion.
  • Contraindicated in pregnancy - linked to foetal problems.
  • Contraindicated in Renal stenosis – ↓Ang II = ↓Efferent arteriole constriction = ↓GFR.

Question 5

Pharmacological treatment of Hypertension - Diuretics:

What are the 3 types?

What do they do?

What are the side effects?

Answer 5

• Loop, Thiazide, K-sparing
• Increase Na+ (and H2O) excretion = ↓BV/BP
• Hypokalaemia (only with loop and thiazide), Lipid abnormalities, and
  Hyperglycaemia (↓insulin release).

Question 6

Pharmacological treatment of Hypertension - SNS Blockers (α/β blockers):

What are the drugs that decrease sympathetic activity?

What are the adrenoreceptor blockers?

Answer 6

α1: Vasoconstriction = ↑TPR = ↑BP
β1: ↑HR and contractility = ↑CO = ↑BP

• • CNS – α2 agonists e.g. Clonidine
  • Ganglionic blockers – e.g. Trimethapan
  • Synaptic blockers – e.g. Reserpine
• • α1 blockers – e.g. Prazosin (↓TPR=↓BP)
  • β1 blockers – e.g. Atenolol (↓HR, CO, RAAS)

Question 7

Pharmacological treatment of Hypertension - Vasodilators (CCBs & K channel openers):

What do K channel openers do? Give an example

What do CCBs do? Give an example

LOOK AT DIAGRAMS!!

Answer 7

• K+ efflux occurs to cause hyperpolarisation, which will ↓VGCC activity. This will lead to ↓[Ca2+] in cell = ↓Ca-CaM-MLCK activity = more relaxation, and vasodilation – e.g. Minoxidil, Diazoxide.
• no Ca influx, so there’s ↓[Ca2+] = ↓Ca-CaM-MLCK activity = more relaxation, and vasodilation – e.g. Amlodipine.

Question 8

How do you select which drugs to use for Hypertension?

Answer 8

There are many issues to consider including side-effects, type of HT, individual’s demographics, co-morbidities, quality of life, costs etc. There are NICE guidelines for Hypertension treatment.