Lecture 4 Treatment of Resistant Hypertension Flashcards
What is the treatment plan if the ACE inhibitor is no longer effective in a hypertensive patient?
Check if medication is being taken correctly
Keep them on ACE inhibitor but add either CCB or thiazide-like diuretic
What is the treatment plan if the CCB is no longer effective in a hypertensive patient?
Check medicine is being taken correctly
Keep them on CCB but add ARB or thiazide-like diuretic
Which patients are more susceptible to problems due to excessive fluid loss using a diuretic?
The elderly, as they are often dehydrated which means they are more susceptible to falling at night to urinate
What is the mechanism of action for thiazide-like diuretics?
Inhibition of Na+/Cl- reabsorption in the DCT by blocking the transporter
Lower doses allow vasodilation (of small arteries) more that diuresis
Where do thiazide-like diuretics target?
C1 protein in the transmembrane of the transporter
What are the pharmacokinetics of thiazide-like diuretics?
Oral administration act 1-2 hours
Administered earlier in the day (don’t interfere with sleep)
Duration of action 12-24 hours
75% plasma protein bound
What is an example of a thiazide-like diuretic?
Indapamide
What are the side effects for thiazide-like diuretics?
Hypokalaemia - low K+ (can cause arrhythmias due to electrical activity changes)
Constipation
Electrolyte imbalance
Postural hypotension
Indapamide: hypersensitivity and skin reactions
What is the 3rd step of treating hypertension?
Triple therapy (ACE/ARB + CCB + thiazide-like diuretic)
What drugs can be considered for patients not responding to step 3 of treatment?
Low-dose spironolactone diuretic (serum K+ not elevated)
Alpha/Beta blocker
Not responding to either = seek expert advice
What is the mechanism of spironolactone?
It is a K+ sparing diuretic by inhibiting aldosterone in the CD, often used on conjunction with other diuretics
What is an example of an alpha blocker?
Doxazosin
What is the effect of alpha blockers?
They block noradrenaline binding to baroreceptors in the peripheral arteries (can lead to fainting)
What is the effect of beta blockers?
They block the B1 receptors in the SAN and AVN which reduces contraction of the ventricles (not a preferred 1st line treatment)
