Antiarrhythmic drugs Flashcards
[Singh-Vaugh Williams Classification]
Sodium channel blockers
Class 1
[Singh-Vaugh Williams Classification]
beta adrenoceptor blockers
Class 2
2 = beta
[Singh-Vaugh Williams Classification]
potassium channel blockers
Class 3
[Singh-Vaugh Williams Classification]
Calcium channel blockers
Class 4
[Class 1 antiarrhythmics]
these acts on what phase of the cardiac action potential?
phase 0
[Class 1 antiarrhythmics]
prolongs the AP duration
Group 1A
[Class 1 antiarrhythmics]
shorten the AP duration
Group 1B
[Class 1 antiarrhythmics]
no effect of AP duration
Group 1C
[Phase of cardiac AP]
Depolarization, due to Na current
Phase 0
[Phase of cardiac AP]
rapid depolarization due to K channel
Phase 1
[Phase of cardiac AP]
due to Ca current; plateau
Phase 2 = plaTWO
[Phase of cardiac AP]
Repolarization, due to K current
Phase 3
[Phase of cardiac AP]
RMP, due to K current
Class 4
[ECG x Phase]
QRS complex
Phase 1 = K current
[ECG x Phase]
ST segment
Phase 2 = plateau
[Class 1A antiarrhythmics]
What are examples of class 1A?
Procainamide
Disopyramide
Quinidine
[Class 1A antiarrhythmics]
Crosses the breast milk, hyperkalemia exacerbates cardiac toxicity; duration 2-3 hours only
procainamide
[Class 1A antiarrhythmics]
SE: cinchonism, ITP, cardiac depression, torsades
Quinidine
Drug of choice to reserve Class 1A overdose, drug-induced arrythmias
sodium lactate
[Class 1B antiarrhythmics]
DOC for ventricular arrythmias post MI and for digoxin-induced arrythmias
lidocaine
only affect ischemic tissues
[Class 1B antiarrhythmics]
hyperkalemia exacerbates cardiac toxicity
lidocaine
[Class 1B antiarrhythmics]
used for neuropathic pain
mexilitine
[Class 1B antiarrhythmics]
associated with increased incidence of orofacial clefts, cardiac defects, fetal hydantoin syndrome
phenytoin
Examples of Class 1 B antiarrhythmics
Mexiletine
Tocainide
Lidocaine
Class 1 drug that is best for post MI
Class 1 B
What are the drugs that can cause agranulocytosis?
CCCAPPIT Me
- Clozapine
- Cotrimoxazole
- Colchicine
- Aminopyrine
- Phenylbutazone
- PTU
- Indomethacin
- Tocainide
- Methimazole
Among Class 1 antiarrythmics, what is the mos arrythmogenic?
Class 1C
[Class 1C antiarrhythmics]
used for refractory arrythmias and contraindicated for post-MI arrythmias
Flecainide
Examples of Class 1C drugs
Propafenone
Flecainide
Encainide
[Class 1 antiarrhythmics]
preferred post MI
Class 1B
[Class 1 antiarrhythmics]
used for refractory arrythmias
Class 1C
Which phase of the cardiac AP does class 2 antiarrythmics affect?
phase 4
Which beta blocker antiarrythmic with class 3 properties?
propanolol
[Class 2 antiarrhythmics]
Used for acute perioperative and thyrotoxic arrythmias
esmolol
Which is the longes acting beta blocker?
nadolol
Beta blocker with a low lipid solubility
atenolol
Beta blocker that lacks local anesthetic effect
timolol
beta blocker with combined alpha and beta blocker
carvedilol, labetalol
Which phase of the cardiac AP that phase 3 antiarrythmics act on?
phase 3
drug class that is highly arrhythmogenic hence also used for refractory arrythmias also. high propensity to cause torsades.
Class 3 antiarrhythmocs
[Class 3 antiarrhythmics]
examples in this class
- Amiodarone
- Ibutilide
- Dofetilide
- Sotalol
[Class 3 antiarrhythmics]
Treatment and prophylaxis of atrial fibrillation
dofetilide
betablocker with class 3 effects is ___
sotalol
[Class 3 antiarrhythmics]
present in breastmilk; treatment for ventricular arrhythmias, beta blocker
sotalol
[Class 3 antiarrhythmics]
strong Ik block produces marked prolongation of action potential and refractory period
amiodarone
[Class 3 antiarrhythmics]
what are the side effects of amiodarone?
- microcrystalline deposits in cornea and skin
- Thyroid dysfunction (hyper/hypo)
- Paresthesia, tremor, pulmonary fibrosis
most efficacious of all antiarrythmic drugs
amiodarone
[Class 3 antiarrhythmics]
drugs used in Afib and atrial flutter
Dronedarone
Amiodarone toxicity causes the following
- Pulmonary fibrosis
- Paresthesia
- Tremors
- Thyroid dysfunction
- Corneal deposits
- Skin deposits
ECG morphology of class IV antiarrythmics
PR interval is consistently increased
CCBs that can cause reflex tachycardia and are proarrythmogenic
Dihydropyridine CCBs
CCB that can cause gingival hyperplasia
verapamil
CCB used for reynaud’s phenomenon and vasospasm
diltiazem
CCB avoided in Vtach
Verapamil, diltiazem
[name that drug]
increase in diastolic Ik of AV node, causes marked hyperpolarization and conduction block; reduced ICa;
only used in ER setting
adenosine
[Antiarrythmics]
used in the ER; for paroxysmal SVT
adenosine
what ion depresses ectopic pacemakers; low level is associated with increased incidence of arrythmias while excessive levels depress conduction and can cause reentry arrythmias
potassium
ion that is effective in some cases of torsades de pointes; sudden and large increase in Mg may cause severe respiratory paralysis
magnesium
