Betablockers

Question 1

beta blockers block betaadrenoreceptors in what areas of the body

Answer 1

heart, peripheral vasculature, bronchi, pancreas and liver

Question 2

what is intrinsic sympathomimetic activity?

what is the clinical implication? (2)

Answer 2

the capacity of betablockers to stimulate as well as blockadrenergic receptors
(partial agonists)
beta blockers with ISA - cause less bradycardia and coldness of extrematies

Question 3

what beta blockers have intrinsic sympathomimetic activity (4)

Answer 3

oxprenolol
pindolol
acebutolol
celiprolol

Question 4

which beta blockers are the most water soluble (4)?

what is the implication of this? (2)

Answer 4

atenolol, celiprolol, nadolol, sotolol

• less likely to cross the BBB therefore cause less sleep disturbance/nightmares
• may need dose adjustment in renal failure

Question 5

why should we caution betablockers in asthma

Answer 5

percipitation of bronchospasm - however some patients may still need the betablocker

Question 6

what betablockers whould we chose if an asthma patient NEEDs a beta blocker

Answer 6

cardioselective ones
(e.g. bisoprolol, atenolol, metoprolol, nebivolol)

Question 7

why caution betablockers in diabetes

Answer 7

reduced warning of hypos (masks tachycardia)
may cause hypos/hypers by interfering in carb metabolism (in patients with or without diabetes)
-not entirely contraindicated
-even more caution if combined with thiazide like diuretic

Question 8

betablockers are good at reducing BP so why are other antihypertensives generally preferred for uncomplicated hypertension?

Answer 8

they are shown to be more effective in reducing incidence of stroke, MI and CV mortality

Question 9

in pheochromocytoma (adrenaline secreting tumour) what should be given with a betablocker to control pulse

Answer 9

phenoxybenzamine (alpha blocker)

jut blocking beta can lead to hypertensive crisis

Question 10

risks of abrupt withdrawl of betablockers (2)

Answer 10

rebound angina for pt with angina

worsening of ischaemia in IHD

Question 11

risks of using betablockers with verapamil

Answer 11

percipitation of HF

Question 12

what is the betablocker of choice in thyrotoxicosis

Answer 12

propranolol

Question 13

what skin condition are betablockers cautioned in

Answer 13

psoriasis - may trigger flare

Question 14

symptoms of beta blocker overdose

Answer 14

sycope
lightheadedness
dizziness
bradycardia
hypotension