What are the side effects of Inderal (propranolol)?

Side Effects of Inderal (Propranolol)

Propranolol commonly causes sleep disturbances, cold extremities, gastrointestinal symptoms, and bronchial irritation, while rare but serious adverse effects include hypoglycemia (particularly in infants), bradycardia, hypotension, and bronchospasm. 1

Common Side Effects

The most frequently reported adverse effects occur in a predictable pattern based on propranolol's beta-blocking mechanism:

Cardiovascular Effects

• Cold hands and feet due to peripheral vasoconstriction 1
• Bradycardia (slowed heart rate), typically mild and asymptomatic in patients without cardiac comorbidities 1
• Hypotension, usually asymptomatic but can occur, particularly at higher doses 1
• Intensification of AV block and arterial insufficiency (Raynaud-type) 2

Central Nervous System Effects

• Sleep disturbances are among the most common complaints, occurring in 2-18.5% of patients, including nightmares, night terrors, and agitation during sleep 1
• Fatigue and lethargy (dose-related with immediate release formulations) 1, 2
• Mental depression, manifested by insomnia, lassitude, and weakness 2, 3
• Vivid dreams (dose-related) 1, 2
• Light-headedness and visual disturbances 2

Gastrointestinal Effects

• Diarrhea 1
• Nausea, vomiting, and epigastric distress 2
• Abdominal cramping and constipation 2

Respiratory Effects

• Bronchial hyperreactivity, including bronchospasm, bronchiolitis, and cold-induced wheezing, reported in up to 12.9% of patients 1
• Labored breathing and respiratory disorders 1

Serious but Rare Adverse Effects

Metabolic

• Severe hypoglycemia is the most concerning adverse effect, particularly in infants and children, potentially causing decreased responsiveness or seizures 1
• Early signs (sweating, tachycardia, shakiness) may be masked by beta-blockade 1
• Later manifestations include lethargy, poor feeding, apnea, seizures, stupor, and loss of consciousness 1

Cardiovascular (Severe)

• Congestive heart failure 2
• Symptomatic bradycardia (rare: 0.1% in one large series) 1
• Symptomatic hypotension (1.2% requiring treatment review) 4
• Cardiac arrest (when combined with certain neuroleptics like haloperidol) 2

Hematologic

• Agranulocytosis 2
• Thrombocytopenic purpura 2

Dermatologic/Allergic

• Anaphylactic/anaphylactoid reactions 2
• Stevens-Johnson Syndrome and toxic epidermal necrolysis 2
• Exfoliative dermatitis and erythema multiforme 2
• Psoriasiform rashes 2

Other Serious Effects

• Systemic lupus erythematosus 2
• Male impotence and Peyronie's disease 2
• Mesenteric arterial thrombosis and ischemic colitis 2

Special Populations and Precautions

Infants and Children

When used for infantile hemangiomas, the adverse event profile shows:

• Overall mild side effects with severe events being rare (5.9% requiring treatment review) 4
• Hypoglycemia in 2.7% of cases 4
• Respiratory symptoms severe enough to modify treatment in 1.8% 4
• Most adverse events do not cause treatment discontinuation 1

Risk Mitigation Strategies

To reduce hypoglycemia risk (particularly critical in infants):

• Administer propranolol with or after feeding 1
• Hold doses during illness with decreased oral intake, vomiting, or diarrhea 1
• Avoid prolonged fasting intervals longer than 6 hours between feedings 1

Monitoring Recommendations

• Evaluate for sleep disturbances, bronchial irritation, and symptomatic bradycardia/hypotension 1
• Monitor blood pressure and heart rate at baseline, 1 and 2 hours after first dose, and after dosage increases ≥0.5 mg/kg/day 1
• Watch for symptoms of hypoglycemia, especially in infants 1

Dose-Related Considerations

Sleep disturbances and fatigue appear to be dose-related with immediate release formulations 1, 2. When these effects occur, treatment modifications may include dose reduction, earlier evening dosing, or early discontinuation 1. Studies show no increased incidence of adverse events when initiating at 2 mg/kg/day versus 1 mg/kg/day in appropriate patients 5.

Neurodevelopmental Concerns

Despite theoretical concerns about propranolol crossing the blood-brain barrier and affecting brain development, large prospective randomized trials showed no appreciable neurodevelopmental differences between propranolol-treated groups and placebo at 96 weeks 1.