BetaBlockers Flashcards
(18 cards)
Mechanism of action
Beta blockers block beta adrenoreceptors in the heart,bronchi,pancreas,liver and peripheral vasculature (blood vessels outside the heart)
They slow the heart down and can depress the myocardium
Beta blockers are equally effective but have different characteristics which effect treatment choice
Beta blockers work where? The receptors
B1 - Heart
B2- Lungs
What is ISA Activity
Intrinsic sympathomimetic Activity - the ability of beta blockers to stimulate and also block adrenergic receptors
We give these specific beta blockers to people because they cause less bradycardia and less cold extremities
Which beta blockers cause less cold extremities
we need ISAs!!!!! ICE PACO
Pindolol
Acebutolol
Cerliprolol
Oxprenolol
Solubility - Water soluable are what? And what do they cause?
Less likely to enter the brain, therefore less sleep disturbances and nightmares - excreted by kidneys - dosage reduction necessary in renal impairment
Examples of water soluable
Less nightmares and sleep disturbances -
Water CANS
Celiprolol
Atenolol
Nadolol
Sotalol
Cardioselective BB
- less effect on beta (bronchial receptors) - lesser effect on airway
- selective but not specific (can still affect airways)
- used in well controlled asthma id no other alternative is present
Which ones are cardio selective (think cardio= gym)
BE A MAN
Bisoprolol
Atenolol
Metoprolol
Acetbutol
Nebivolol
Non cardio selective is sotalol
Short duration of action
- have to be given two or three times a day
- may be available as MR preps and can be given once daily for hypertension
Long duration of action
- given once a day only
Long duration of action
Give once daily
BACN!!!!
Bisoprolol
Atenolol
Celiprolol
Nadolol
SIDE EFFECTS
- fatigue
- coldness of exterimeties (less common with ISA)
- Sleep disturbances with nightmares - less common with water soluable
- Bradycardia(reduce heart rate)
- hypotension
- can cause hypoglycaemia or hyperglycaemia
- can also mask the symptoms of hypoglycaemia
- beta blockers can effect carbohydrate metabolism, causing hypogylcaemie or hyperglycaemia in patients with or without diabetes; they can also interfere with metabolic and autonomic response to hypoglycaemia, thereby masking symptoms of tachycardia
Can beta blockers be given to patients in asthma?
Precipitates bronchospasm (avoid in patients with a history of asthma)
- give to patients with well controlled asthma,copd when there is no alternative
- for existing HF or following MI
= In this situation you should give a cardioselective beta blocker with caution,initiated at a low dose by a specialist and monitored for side effects - atenolol,Bisoprolol,metoprolol,nebivolol and acebutol BE A MAN!!! Have less effect on b2 (bronchial receptors) receptors, therefore relatively cardioselective but not cardiospecific (still have an effect on airways and not free of side effects)
Are they contraindicated in diabetes?
- use with caution in diabetics but they are not contraindicated but cardioselective may be preferred
- affect carbohydrate metabolism (cause hyperglycaemia or hypogylcaemia in patients with or without diabetes)
- avoid in patients with frequent episodes of hypoglycaemia
- interfere with autonomic and metabolic responses to hypoglycaemia,thereby masking symptoms of hypoglycaemia eg.tachycardia
- use cardioselective beta blockers for diabetics and asthmatics
Uses of beta blockers
Hypertension (reduce cardiac output)
Angina(improves exercise tolerance and relieves angina symptoms)
Myocardial infarction (reduces recurrence rate), atenolol,metoprolol
Arrhythmias - esmolol and sotalol
Heart failure- reduces mortality in stable heart failure eg. Bisoprolol,carvedilol and nebivolol - contraindicated in unstable heart failure
Anxiety (propranolol)
Migraine prophylaxis (propranolol)
Glaucoma (betaxolol,levobunolol and timolol)
Throtoxicosis (propranolol)
Beta blockers contraindications
- Asthma, COPD and bronchospasm - Generally avoid if no alternative give cardio selective and under specialist supervision
-Marked Bradycardia - slower than normal heart rate
- Prinzmetal angina - rare and severe type of angina
- 2nd and 3rd degree AV block - AV block is when an electrical signal that controls the heart heat are blocked partially or completely
- unlicensed heart failure
Beta blockers - Cautions
- diabetes can cause hypoglycaemia and hyperglycaemia with patients that do or don’t have diabetes
- 1st degree av BLOCK
- Symptoms of thyrotoxicosis and hypoglycaemia may be masked
- verapamil or diltiazem (can cause heart block)
- may reduce response o adrenaline (epinephrine) - EpiPen!!!!
Important IV interaction
IV verapamil and beta blocker - risk of hypotension and bradycardia
