Drug Induced Cardiac Injury

Question 1

3 Mechanisms of Drug Induced Cardiac Injury

Answer 1

QTc Prolongation (Torsades de Pointes)
HF
Myocardial Ischemia

Question 2

Normal QTc

Answer 2

men < 470
women < 480

Question 3

QTc prolongation

Answer 3

> /= 500
/= 60 increase from baseline

Question 4

Meds that cause QTc Prolongation ABC’s
A:

Answer 4

Antiarrhythmics:
- amiodarone
- sotalol
- dofetilide

Question 5

Meds that cause QTc Prolongation ABC’s
B:

Answer 5

Antibiotics:
- Fluoroquinolones (-floxacin)
- macrolides (erythromycin, clarithromycin, azithromycin, etc.)

Question 6

Meds that cause QTc Prolongation ABC’s
C:

Answer 6

Antipsychotics:
- chlorpromazine
- fluphenazine
- perphenazine
- prochlorperazine
- haloperidol

Question 7

Meds that cause QTc Prolongation ABC’s
D:

Answer 7

Antidepressants:
- Citalopram
- TCAs (Amitriptyline, Doxepin, Imipramine, Nortriptyline, etc.)

Question 8

Meds that cause QTc Prolongation ABC’s
E:

Answer 8

Antiemetics:
- ondansetron

Question 9

Meds that cause QTc Prolongation ABC’s
F:

Answer 9

Antifungals:
- azole antifungals

Question 10

TdP Prevention

Answer 10

• avoid agents in pats with baseline QTc > 450
• reduce/DC if pats QTc increases > 60 from baseline
• DC if QTc > 500
• Maintain K>4 and Mg>2

Question 11

TdP Treatment

Answer 11

• DC offending agent
• Mg push or infusion (push if no pulse)
• Transcutaneous pacing
• Isoproterenol infusion ($$$, can use epinephrine or atropine instead)
• if hemodynamically unstable -> cardioversion or defibrillation

Question 12

3 main causes of drug induced HF

Answer 12

• Sodium and volume retention
• Direct cardiotoxicity -> cardiomyopathy
• Negative inotropy

Question 13

Agents that cause sodium and volume retention (HF)

Answer 13

• NSAIDs
• Steroids
• Thiazolidinediones (TZDs)

Question 14

Agents that cause cardiomyopathy

Answer 14

• Chemotherapeutic agents (anthracyclines, alkylating agents)
• Trastuzumab
• Alcohol

Question 15

Agents that cause Negative Inotropy

Answer 15

NDCCBs (diltiazem, verapami)
Beta blockers (-olol)

Question 16

Anthracycline induced cardiomyopathy

Answer 16

Most common agents: doxorubicin, daunorubicin

Risk factors:
- cumulative dose > 400 mg/m^2
- limit dose to 550 mg/m^2

Prevention:
- Dexrazoxane

Question 17

Trastuzumab induced cardiomyopathy

Answer 17

Inhibition of HER2 receptors
Evaluate LVEF in all pats prior to and during treatment

Treatment:
- dose adjust/DC
- consider ACE/ARB or BB to treat HF

Question 18

3 mechanisms of drug induced myocardial ischemia

Answer 18

• Increased HR and contractility -> increased myocardial O2 demand
• Vasospasm -> decreased myocardial O2 supply
• Drug induced ACS

Question 19

Agents that cause increased O2 demand

Answer 19

• cocaine
• beta agonists (albuterol)
• sympathomimetics
• withdrawal of beta blockers
• potent vasodilators

Question 20

Agents that cause vasospasm

Answer 20

• cocaine
  -triptans

Question 21

Agents that cause drug induced ACS

Answer 21

• cocaine
• COC
• NSAIDs
• estrogens
• antimigraine agents
• HIV agents
• rosiglitazone

Question 22

Cocaine Induced MI Treatment

Answer 22

Chest pain
- ASA
- benzodiazepines

Persistent HTN
- benzodiazepines
- IV nitroglycerin

Other acute ACS treatment
- possibly avoid BB

Question 23

NSAID induced cardiotoxicity

Answer 23

Arachidonic acid cascade -> vasoconstriction + platelet aggregation

risk is highest first 7 days of therapy

duration of therapy does not appear to increase risk

Risky doses:
- >1200mg/day ibuprofen
- >750mg/day naproxen