Class 1 Anti-Arrhythmics Flashcards Preview

Cardiovascular Drugs > Class 1 Anti-Arrhythmics > Flashcards

Flashcards in Class 1 Anti-Arrhythmics Deck (20)
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1

Examples: Class 1A

- Quinidine
- Disopyramide

2

Example: Class 1B

- Lidocaine

3

Example: Class 1C

- Flecainide

4

Indications of class 1's?

- Tachyarrhythmias

5

What are the contraindications of class 1A's?

- Heart failure
- Heart block
- Ischaemic heart disease (flecainide)

6

Cautions for use of class 1's?

- Pregnancy
- Prostatic enlargement
- Glaucoma
- Hepatic impairment
- Renal impairment

7

How do class 1's work?

- Inhibit sodium channels

8

How do A, B and C differ if they act on the same channels?

- They have different speeds of binding

9

What effect do 1A's (quinidine and disopyramide) have?

- Prolong cardiac action potential

10

What effect do 1B's (lidocaine) have?

- Shorten cardiac action potential

11

What effect do 1C's (flecainide) have?

- Do not affect action potential

12

How are class 1's administered?

- Oral or IV depending on circumstance

13

What adverse reactions are there for class 1 anti arrhythmics?

- Arrhythmogenic and may prolong QT interval
- Anticholinergic effects
- Seizures (flecainide)

14

How are some class 1's metabolised?

- Through the cytochrome P450 system so very susceptible to drug interactions

15

What drugs should you avoid copharmacy with?

- Drugs that may prolong QT interval (e.g. amiodarone, antihistamines)
- Drugs which have a negatively ionotropic effect

16

What other (metabolic) condition commonly goes along with arrhythmias?

Hypokalaemia

17

What complication does the hypokalaemia cause?

- Can't use diuretics with anti-arrhythmics as they lower potassium further

18

What should patients be warned to avoid because of the tachyarrhythmic side effect?

- Avoid triggers that cause tachyarrhythmias such as drinking coffee

19

What should be done to doses of disopyramide in patients with renal failure?

- Dose should be halved as 75% of the drug excreted through renal

20

What can happen to the half life of some class 1 antiarrhythmics during hepatic impairment?

- Can be increased