Contraindicated Medications in Congenital Heart Disease
Estrogen-containing oral contraceptive pills are contraindicated in patients with congenital heart disease who have cyanosis with intracardiac shunts, severe pulmonary arterial hypertension, or Fontan repair due to increased thromboembolism risk. 1
Hormonal Contraceptives: Clear Contraindications
Absolute Contraindications
- Estrogen-containing oral contraceptives are explicitly not recommended (Class III recommendation) in the following CHD populations 1:
- Patients with cyanosis related to intracardiac shunts
- Severe pulmonary arterial hypertension (PAH)
- Post-Fontan repair patients
- Atrial fibrillation with CHD
The mechanism behind this contraindication is the prothrombotic effect of estrogen, which significantly increases thromboembolism risk in patients already at elevated baseline risk from their cardiac anatomy 1.
Use with Extreme Caution (Near-Contraindication)
- Progesterone-only contraceptives (medroxyprogesterone, progesterone-only pills, levonorgestrel) should be used with extreme caution in patients with heart failure, as these agents cause fluid retention that can precipitate cardiac decompensation 1, 2
- Medroxyprogesterone acetate specifically may exacerbate heart failure symptoms and requires close monitoring for weight gain and peripheral edema 2
- The "morning after pill" (levonorgestrel "plan B") poses risks of acute fluid retention and should be explained to at-risk patients 1
Antiarrhythmic Medications: Prophylactic Use Contraindicated
Prophylactic antiarrhythmic therapy with Class Ic medications (flecainide, propafenone) or amiodarone is potentially harmful (Class III: Harm) in patients with adult congenital heart disease who have asymptomatic ventricular arrhythmias. 1
This represents a critical pitfall—the temptation to treat asymptomatic arrhythmias prophylactically can cause more harm than benefit in this population. These medications should only be used for symptomatic or hemodynamically significant arrhythmias, not for prevention 1.
Anticoagulation Considerations
Warfarin in Pregnancy
- Warfarin requires prepregnancy counseling (Class I recommendation) due to significant maternal and fetal risks 1
- While not absolutely contraindicated, the teratogenic effects necessitate informed decision-making and potential medication switching before conception 1
Critical Safety Measures for All Medications
Intravenous Medication Administration
- All intravenous lines must have meticulous air bubble removal in patients with intracardiac right-to-left shunts to prevent paradoxical air embolism (Class I recommendation) 1
- This applies to any medication given intravenously and represents a life-threatening complication if overlooked 1
Medications Crossing into Breast Milk
- Women with CHD requiring cardiovascular medications should clarify potential effects on infants with a pediatrician, as many cardiac medications cross into breast milk 1
- However, breastfeeding itself is safe in women with CHD 1
Risk-Based Approach to Medication Selection
Highest Risk Populations Requiring Specialized Medication Management
The following CHD patients require expert consultation before any significant medication changes 1:
- Prior Fontan procedure
- Severe pulmonary arterial hypertension
- Cyanotic CHD
- Complex CHD with residual lesions (heart failure, valve disease, anticoagulation needs)
Beta-Blockers: Beneficial Exception
- Beta-blockers are beneficial (Class IIa) in adults with repaired severe complexity CHD and frequent or complex ventricular arrhythmias to reduce sudden cardiac arrest risk 1
- This represents one of the few antiarrhythmic strategies with demonstrated benefit in asymptomatic patients 1
Common Pitfalls to Avoid
Do not prescribe estrogen-containing contraceptives to any woman with cyanotic CHD, PAH, or Fontan physiology—this is an absolute contraindication with potentially fatal consequences 1
Do not initiate prophylactic Class Ic antiarrhythmics or amiodarone for asymptomatic ventricular arrhythmias—this causes harm rather than benefit 1
Do not overlook fluid retention risks with progesterone-based contraceptives in heart failure patients—monitor weight and edema closely 1, 2
Do not use intravenous lines without air filters in patients with right-to-left shunts—paradoxical embolism can be fatal 1