Beta-blockers Flashcards
beta-blockers block
beta-adrenoceptors in heart, peripheral vasculature, bronchi, pancreas, & liver.
Intrinsic sympathomimetic activity
partial agonist activity represents capacity of BB to stimulate as well as to block adrenergic receptors.
~ Celiprolol, pindolol, acebutolol, & oxprenolol hydrochloride =intrinsic sympathomimetic activity;
~ tend to cause less bradycardia than other beta-blockers + less coldness of extremities.
Water-soluble beta-blockers
~ Atenolol, celiprolol hydrochloride, nadolol, & sotalol hydrochloride
~ less likely to enter brain, & may therefore cause less sleep disturbance and nightmares.
~ excreted by kidneys and dosage reduction often necessary in renal impairment.
Beta blockers with intrinsically longer duration of action
~ Atenolol, bisoprolol fumarate, celiprolol hydrochloride, & nadolol
~ need to be given only once daily.
Beta blockers contraindications
~ slows heart & depress myocardium;
~ contra-indicated in second- or third-degree heart block.
~ Avoided in patients with worsening unstable heart failure; care required when initiating beta-blocker in those with stable heart failure
~ history of asthma
Cardioselective BB
Atenolol, bisoprolol fumarate, metoprolol tartrate, nebivolol, & (to lesser extent) acebutolol
~ have less effect on beta2 (bronchial) receptors so cardioselective,
BB side effects
~ Nightmares/sleep disturbances (less in water soluble ones)
~ fatigue
~ cold extremities
~ participate bronchospasm
~ cause hypoglycaemia / hyperglycaemia in patients with or without diabetes
~ mask symptoms such as tachycardia
HTN and BB
~ reduce cardiac output, alter baroceptor reflex sensitivity, & block peripheral adrenoceptors. ~ Some depress plasma renin secretion.
~ are effective for reducing BP but other drugs more effective for reducing incidence of stroke, MI, & CV mortality, especially in elderly.
~ used to control pulse rate in patients with phaeochromocytoma. However, never be used alone as beta-blockade without concurrent alpha-blockade may lead to a hypertensive crisis.
~ phenoxybenzamine hydrochloride ALWAYS be used together with beta-blocker.
Angina & BB
~ By reducing cardiac work to improve exercise tolerance & relieve symptoms in patients with angina.
~ As with HTN no good evidence of superiority of any 1 drug, although occasionally patient will respond better to 1 beta-blocker than to another
~ some evidence that sudden withdrawal = exacerbation of angina SO gradual reduction of dose preferable when beta-blockers stopped
~ risk of precipitating heart failure when beta-blockers & verapamil used together in established ischaemic heart disease.
MI and BB
Arrhythmias and BB
HF and BB
Thyrotoxicosis and BB
BB other uses
~ Anxiety in pt with tremor, palpitations, tachycardia
~ Migraines prophylaxis
~ glaucoma
Esmolol
HTN in peri-operative period
SHORT HALF-LIFE
Labetalol
HTN in pregnancy
Hepatoxic
Sotalol
Class 3 anti-arrhythmic
Side effects - TdP
ice PACO (beta blockers)
intrinsic sympathomimetics activity
- less bradycardia
- less coldness of extremities
Pindolol
Acebutol
Celiprolol
Oxprenolol
water CANS (beta blockers)
water soluble, less likely to cross BBB
~ less nightmares & sleep disturbances
~ reduce dose in renal impairment
Celiprolol
Atenolol
Nadolol
Sotaolol
Be A MAN (beta blockers)
cardio-selective = less bronchospasms
~ well-controlled asthma, under specialist
Bisoprolol
Atenolol
Metoprolol
Acebutol
Nebivolol
BACoN (beta blockers)
OD dosing
~ intrinsically longer duration of action
Bisoprolol
Atenolol
Celiprolol
Nadolol
Beta blockers side effects
~ bradycardia
~ hypotension
~ HyPERglycaemia
~ masks symptoms of hyPOglyacemia (masked)
beta blockers contra-indications
~ asthma = bronchospasms
~ worsening unstable HF
~ 2nd/3rd heart block
~ severe HTN + bradycardia
Beta blockers interactions
- Asystole HTN
~ verapamil injection - HyPERglycaemia
~ avoid in DM
~ TLD
