Lecture 10 Hypertension II Flashcards Preview

CDL301 Cardiovascular Pharmacology > Lecture 10 Hypertension II > Flashcards

Flashcards in Lecture 10 Hypertension II Deck (45)
Loading flashcards...

What is the main therapeutic strategy in the treatment of hypertension

The main therapeutic strategy in the treatment of hypertension is to reduce the peripheral resistance


What is the first line choice of therapy in patients with hypertension these tend to be patients who are over 55 and/or Afro-Caribbean

Ca2+ channel blockers


Which Ca2+ channels are targeted in hypertension

L-type Ca2+ channels


What are the clinical indications of Ca2+ channel blockers

Hypertension IHD/angina and arrhythmias such as tachycardia


Which cells do Ca2+ channel blockers act on

Ca2+ channel blockers act on peripheral resistance directly by blocking the Ca2+ channels in the membrane of vascular smooth muscle


What are the three classes of Ca2+ channel blocker

Dihydropyridines phenylalkylamines and benzothiazepines


Which are the main class of Ca2+ channel blockers used in hypertension because of their vasodilatory effects give examples

Dihydropyridines – amlodipine nifedipine and felodipine


Which classes of Ca2+ channel blockers are used in IHD and arrhythmias give examples

Phenylalkylamines – verapamil and benzothiazepines – diltiazem


Why are diltiazem and verapamil used in IHD and arrhythmia

They are rate-limiting mediations that reduce heart rate and oxygen demand


When are dihydropyridines used in IHD and arrhythmia

If patients already on β blockers (which is already reducing heart rate) then amlodipine can be a useful add on


What is the main effect of dihydropyridine CCBs

Dihydropyridines are peripheral vasodilators that preferentially affect vascular smooth muscle and cause peripheral arterial vasodilation


What is the main effect of phenylalkylamine CCBs

Verapamil mainly acts on the heart where it has a negative chronotropic and inotropic effect


When is verapamil contraindicated

In heart failure


Which drug belongs to the benzothiazepine class of CCBs



What are the effects of benzothiazepines

They have an intermediate between heart and peripheral vascular affects


When are benzothiazepines used

They are used in hypertension and some arrhythmias


Which class of CCBs are primarily used in hypertension



How does activity of dihydropyridines differ between the class

Nifedipine is relatively short acting and needs regular administration or controlled release. In contrast amlodipine is intrinsically longer acting


Which is the only CCB licenced in heart failure patients



What are the three categories of adverse effects due to CCB use in hypertension

Side effects due to peripheral vasodilation negative chronotropic effects and negative inotropic effects


Which class of CCB side effects are mainly associated with the dihydropyridines

Peripheral vasodilation effects such as flushing headache oedema and palpitations


Why do palpitations sometimes occur as a side effect of CCB use

Dihydropyridines cause palpitations as this is a natural reflex of the heart in order to restore blood pressure by raising heart rate


Which side effects are mainly associated with verapamil and diltiazem CCBs

Negative chronotropic effects such as bradycardia and atrioventricular block


What side effects are predominantly associated with verapamil

Worsening of heart failure due to negative inotropic effects. Also constipation is often seen most likely due to an inhibition of smooth muscle contraction in the colon


Diltiazem verapamil and β blockers are contraindicated in patients with heart block due to the negative chronotropic effects. When is the only time that these drugs may be used and why

The only time that diltiazem verapamil and β blockers may be used in patients with conduction defects is when they’ve had a pacemaker fitted. In these patients if the drug stops occasional electrical activity then the pacemaker can stimulate atria or ventricles only if needed


Where are the α1 receptors found and how can they be targeted therapeutically in hypertension

α1 receptors are postsynaptic receptors causing smooth muscle contraction. α1 blockers reduce vasoconstriction and cause vasodilation


Give some examples of α1 blockers

Doxazosin prazosin indoramin and terazosin


What is the main side effect with α1 blockers

Upon standing up the bodies response is to trigger vasoconstriction via stimulating the α1 receptors. One key issue with α1 blockers is that they cause postural hypotension which can lead to syncope


Why are α1 blockers also licenced in prostatic hypertrophy

Hypertrophy of the prostate blocks outflow of urine through the urethra. However the bladder neck and prostate itself contains smooth muscle that contract via α1 receptors. Blocking these receptors with indoramin alfuzosin and Tamsulosin alleviates some of the restricted flow


How can the α2 receptors be targeted in hypertension

The α2 adrenoceptors are found on the presynaptic membrane in the brainstem. Stimulation of these α2 receptors decreases noradrenaline release and hence the effects of sympathetic nervous system stimulation