Antihypertensive drugs

Question 1

Epidemiological defintion of HT and stages

Answer 1

>140/90 target
pre 120-139/80-89
1: >14/90
2: >160/100
3: >180/110

Question 2

HT risk

problem of HT

Answer 2

Stroke, coronary artery disease and renal disease. Treating HT can improve long term outcomes in terms of lowering risk of stroke and CAD

Common, many people undiagnosed

Question 3

Lifestyle changes to improve HT

Answer 3

Diet: lower sodium (aim to <80mmol/day)
Weight loss
Exercise
Reduce alcohol

Question 4

Problems with HT treatment

Answer 4

Lifelong, concurrent diseases, perceived treatment benefit, asymptomatic

Question 5

Hypertension drugs

Answer 5

ACEi/A2 antags: ACEi 1st line
BB: 2nd/3rd line therapy
CCB: usually nifedipine, amlodipine for HT. 2nd/3rd line
Diuretics: 1st line therapy
AB: 3rd line/4th?

Question 6

Thiazide diuretics: common + mechanism

what happens to volume over time?

Answer 6

Bendrofluazide, chlorthalidone. Good ombo with ACEi

Mechanism: inhibit Na+/Cl- (co-transport) in DCT. Causes natriuresis.
Lowers BP with subdiuretic doses.
Also open vascular K+ channels, vasodilate. (longer repolarisation, less likely to vasoconstrict)
Can take 12 weeks

BP stays lower, but volume increases due to RAAS, so prologed lowered BP due to vasodilation (unsure supposedly)

Question 7

Thiazide side effects

Answer 7

Metabolic: increase glucose (reduce glucose tolerance); increase urate (reduce urate clearance); lower K+, Na+, Mg2+. (Hyponatraemia, hypokalaemia)
Diuresis
Erectile dysfunction

Question 8

Loop diuretics: name and mechanism

Answer 8

Frusemide

Inhibit NKCC (Sodium, potassium 2chloride co-transporter) in Ascending LoH
Are very potent, large diuresis.

Little anti HT effect alone, not a monotherapy, potent with ACEi. e.g Heart failure

Question 9

Loop diuretics side effects

Answer 9

• Decrease Na+, K+, Mg2+ (Hyponatraemia, hypokalaemia)
• High iv doses, is ototoxic: deafness and tinnitus
• Dehydration

Question 10

Potassium sparing diuretics: example and mechanisms

Side effects

Answer 10

Spironolactone, aldosterone antagonist, mild diuretic
Inhibits ENaC in distal tubule/collecting duct, so prevents Na reabsorption here, but also concentrates potassium in ECF.

Hyperkalaemia, gynaecomastia (oestrogen like structure), dehydration.

Not first line, used when resistant HT

Question 11

Misc anti HT’s

Answer 11

Vasodilators: Minoxidil, hydrlazine
Centrally acting, decrease sympathetic tone:
-Methyldopa: NE prodrug, a2 agonist. Can be used in pregnancy, but drowsy, depression, hepatitis
-Clonidine: a2 and imidazoline agonist
-Minoxidine: imidazoline agonist

Question 12

When to use drug therapy

Answer 12

• On average >160/100
• > 140/90 + co-morbidities such as CVD, CAD, LVH, HF, DM, proteinuria/renal impairment
• Calculate 10 year CV risk, if >20%

Question 13

British HT society guidelines (pg 65)

Answer 13

YOUNGER (<55) and non black: A (or B); add A (or B) + C or D; A( or B) + C + D; resistant, alpha blocker or spironolactone or other diuretic

OLDER or black: C or D; C or D + A(or B); C+D+A(or B); resistant HT, add spironolactone, alpha blocker or other diuretic

reason older is C or D first line as less RAAS based, better effect

Question 14

Effective drug combination

Answer 14

Diuretic + ACEi + vasodilator (CCB/Alpha blocker)

Question 15

Sensible drug prescriptions for all of the types

Answer 15

ACEi: HT + heart failure
BB: HT + angina/heart failure. (use if specifically MI, CCF, AFib)
Diuretics: HT+ HF
Alpha blocker: HT + prostatism

Question 16

Pregnancy and HT: complications, drugs that you would use

Answer 16

Bad for mother and baby, best is deliver if of age.
Pre-eclampsia if increased BP + proteinuria

CAN USE: Centrally methyldopa; BB, metoprolol/labetalol; CCB nifedipine; VD’s hydralazine

DON’T USE: ACEi/A2A; atenolol (IUGR); diuretics (reduced placental flow)

Question 17

HT in elderly

Answer 17

Can treat the HT, as as just as responsive

Question 18

Polypills

Answer 18

Small doses of all the drugs due to synergistic effect.
Idea that all such low doses will give no side effects.

Suggestion that everyone over 50 on polypill
use versus just one, however can not change regiment of each drug