Antiarrhythmic Agents
Antiarrhythmic Agents
Antiarrhythmic Agents
PRESENT BY:
1. ALICIA KUAN LEE CHING 1507591
2. ANG YONG XIN 1403680
3. CHAN CHUN KEAT 1503102
4. LEE SU XIAN 1507723
UDDD3224 PHARMACOLOGY 5. SOH KAE SIANG 1507031
Cardiac arrhythmia
Irregular pattern of heartbeat or changes in the
sequence of electrical impulses
Classified
based on
electrophysiologic effects
Refinement of the Vaughan
Williams classification system
Comparison of Class IA, IB and IC
Three classes have different efficacy
for reducing the slope of phase 0.
(Greatest) IC > IA > IB (Lowest)
Class IA
- Procainamide Oral, Intravenous, 99% metabolized to N- Hypotension
Hydrochloride Intramuscular acetyl-procainamide Long term therapy leads to reversible
(3-5 hours) (hepatic) (CYP2D6) lupus-related symptoms
Renal elimination
Class IB
- Lidocaine Intravenous 95% metabolized to Adverse effect similar to
Hydrochloride Oral (extensive monoethylglycine local anesthetic which
first pass effect) xylidide and glycine are neurologic
(1.5-2 hours) xylidide
Class IC
Class Route of Pharmacokinetics Toxicity
administration
and t1/2
Class IC
- Flecainide Oral Undergo hepatic and Proarrhythmic effect
Acetate (20 hours) kidney metabolism
Propranolol
Esmolol
Route of Administration
IV
Orally
Mechanism of Action
Beta-blockers divided into two classes:
non-selective blockers (block both β1and β2 receptors)
selective β1 blockers
Amiodarone
Dronedarone
Ibutilide
Class III
Dofetilide Sotalol
Mechanism of Action (Amiodarone)
inhibit K+ channels (block IKr)
→ prolong QT interval
→ prolong ventricular action
potential
→ prolong effective refractory
period (ERP)
Pharmacokinetics
• bioavailability 35-65%
• t1/2 = extremely long (weeks)
Amiodarone (distributes extensively in adipose tissue)
• metabolized by CYP3A4
Torsades de pointes
Gray-blue
discoloration
Hypothyroidism/
Pulmonary fibrosis hyperthyroidism
Bradycardia
Optic neuropathy
(corneal deposits)
Hepatotoxicity
Class IV
Antiarrhythmics
Class IV Antiarrhythmics
(Ca2+ channel blockers)
Verapamil Diltiazem
Pharmacokinetics
• half-life of 4–7 hours
AV block
Peripheral oedema
Lassitude
Other
Antiarrhythmic
Drugs
Other Antiarrhythmic Drugs
Magnesium
Adenosine
Sulphate
Adenosine
Mechanism of Actions
Adenosine receptors
- A1 (Atria)
- A2A (Coronary Blood Vessels)
Activate inward rectifier K+ current
Inhibit calcium current
- Suppress calcium dependent action potentials
Route of Administration Pharmacokinetics
Intravenous
Half Life
Pharmacodynamics <10
Antagonist seconds