Anti-Arrythmics Flashcards
What are the two drugs used to treat acute bradycardia?
What is their purpose?
- Atropine
- Isoprenaline
The medicines act as a bridge until more definitive pacing, or while the underlying cause of bradycardia is treated.
What class of drug is atropine and how does it work?
How is it given?
- Antimuscarinic
- Reversible antagonist of muscarinic Ach receptors, blocks the action of the vagus nerve on the SAN and AVN
- Given as an IV bolus
What class of drug is isoprenaline and how does it work?
How is it given?
- Non selective beta-adrenoceptor agonist
- Positive inotropic and chonotropic effects on the heart via B1 receptor, increases HR and contractility
- Given as an IV infusion
What class of drug is flecainide?
How does it work?
Class 1c antiarrythmic
It blocks Na+ channels, in the AV node, slowing conduction. Used in AF.
What are side effects of flecainide?
- Dizziness, drowsiness, abdo upset
What is a major contraindication to flecainide?
Structural heart disease, can cause sudden death
What class of drug is bisoprolol?
How does it work?
What are the side effects?
A class 2 antiarrhythmic - a beta blocker
It blocks B1 receptors, particularly in the AVN
Bronchospasm, hypotension
What are amiodarone and sotalol?
How does it work?
What are the side effects?
A class 3 antiarrhythmic
Block outward efflux of K+ channels in phase 3 repolarisation. Prolongs the AP.
Skin pigmentation and photosensitivity, pulmonary fibrosis, hepatic injury, bradycardia, hypothyroidism, optic neuritis
What are verapamil and diltiazem?
Calcium channel blockers (NDHP), class 4 antiarrhythmics
They block L type calcium channels, depressing calcium mediated depolarisation and recovery of the SAN and AV nodes
Why should you never give a NDHP CCB with a beta blocker?
ASYSTOLE!!!
