Arrythmias Flashcards
Beta blockers block the effects of which hormone?
Which condition is contraindicated and why?
They block the effects of Adrenaline.
This is contraindicated in Diabetes, it masks Adrenergic symptoms of hypoglycaemia (fast heart rate, tremors, anxiety).
Beta blockers can prolong Hypoglycaemia, how?
By binding to adrenaline receptors, stopping the Liver from producing Glucose
Which diabetes medicines do Beta blockers interact with?
Why?
Medicines that increase insulin: Insulin, Sulfonylureas, Meglitinides
Beta blockers mask symptoms of hypoglycaemia caused by these medicines
What counselling points should be given to patients with diabetes on Beta blockers?
Recognise non-adrenergic hypo symptoms, monitor blood glucose, carry glucose tabs.
Beta blockers (especially non selective) can bind to which receptors in the lungs?
What does this cause?
They can bind to B2 receptors, causing airways to narrow, making asthma symptoms worse, and bronchospasm.
How do beta blockers reduce the effect of B2 agonists
By blocking B2 receptors, preventing agonists from binding for muscle relaxation and airway opening.
What beta blockers should be given to patients with Asthma
Cardio-selective : Atenolol, metoprolol
How do Calcium channel blockers work?
They prevent Calcium (which makes the heart contract) from entering cells in the heart and blood vessel walls.
This slows heart rate, reduces blood pressure and chest pain.
Which CCBs mainly affect blood vessels?
Dihydropyridine’s: Nifedipine, Amlodipine
Which CCBs affect blood vessels AND the heart? So can be used in arrhythmias
Non-dihydropyridines: Diltiazem, Verapamil
What are the main interactions for Non-Dihydropyridine CCBs? and what do they cause?
They increase levels of Statins and Digoxin, causing increased myopathy.
Grapefruit juice increases levels of Nifedipine, Verapamil and Diltiazem, causing greater side effects - ankle swelling, dizziness.
How does Amiodarone work?
It blocks Sodium, Potassium and Calcium channels to slow heart rate.
What does Amiodarone interact with?
It increases amounts of Warfarin and Digoxin.
Increases myopathy risk with statins (lower dose)
How does Flecainide work?
Possible interaction?
Blocks Sodium channels to slow electrical signals in the heart.
Can increase Digoxin levels
How does Sotalol work?
Interactions?
It combines beta blocker effect with potassium channel blocking, to slow heart rate and prolong electrical recovery.
Interacts with BBs and QT prolonging drugs - dangerous heart rhythm risk.
