Drug Induced Cardiac Injury Flashcards
3 Mechanisms of Drug Induced Cardiac Injury
QTc Prolongation (Torsades de Pointes)
HF
Myocardial Ischemia
Normal QTc
men < 470
women < 480
QTc prolongation
> /= 500
/= 60 increase from baseline
Meds that cause QTc Prolongation ABC’s
A:
Antiarrhythmics:
- amiodarone
- sotalol
- dofetilide
Meds that cause QTc Prolongation ABC’s
B:
Antibiotics:
- Fluoroquinolones (-floxacin)
- macrolides (erythromycin, clarithromycin, azithromycin, etc.)
Meds that cause QTc Prolongation ABC’s
C:
Antipsychotics:
- chlorpromazine
- fluphenazine
- perphenazine
- prochlorperazine
- haloperidol
Meds that cause QTc Prolongation ABC’s
D:
Antidepressants:
- Citalopram
- TCAs (Amitriptyline, Doxepin, Imipramine, Nortriptyline, etc.)
Meds that cause QTc Prolongation ABC’s
E:
Antiemetics:
- ondansetron
Meds that cause QTc Prolongation ABC’s
F:
Antifungals:
- azole antifungals
TdP Prevention
- 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
TdP Treatment
- 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
3 main causes of drug induced HF
- Sodium and volume retention
- Direct cardiotoxicity -> cardiomyopathy
- Negative inotropy
Agents that cause sodium and volume retention (HF)
- NSAIDs
- Steroids
- Thiazolidinediones (TZDs)
Agents that cause cardiomyopathy
- Chemotherapeutic agents (anthracyclines, alkylating agents)
- Trastuzumab
- Alcohol
Agents that cause Negative Inotropy
NDCCBs (diltiazem, verapami)
Beta blockers (-olol)
Anthracycline induced cardiomyopathy
Most common agents: doxorubicin, daunorubicin
Risk factors:
- cumulative dose > 400 mg/m^2
- limit dose to 550 mg/m^2
Prevention:
- Dexrazoxane
Trastuzumab induced cardiomyopathy
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
3 mechanisms of drug induced myocardial ischemia
- Increased HR and contractility -> increased myocardial O2 demand
- Vasospasm -> decreased myocardial O2 supply
- Drug induced ACS
Agents that cause increased O2 demand
- cocaine
- beta agonists (albuterol)
- sympathomimetics
- withdrawal of beta blockers
- potent vasodilators
Agents that cause vasospasm
- cocaine
-triptans
Agents that cause drug induced ACS
- cocaine
- COC
- NSAIDs
- estrogens
- antimigraine agents
- HIV agents
- rosiglitazone
Cocaine Induced MI Treatment
Chest pain
- ASA
- benzodiazepines
Persistent HTN
- benzodiazepines
- IV nitroglycerin
Other acute ACS treatment
- possibly avoid BB
NSAID induced cardiotoxicity
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
