Propranolol is a non-selective beta-blocker (β1+β2) indicated for hypertension, angina, arrhythmias, essential tremor, migraine, and situational anxiety. It is lipophilic and crosses the blood-brain barrier.
Also known as: Inderal
Beta-blocker + calcium channel blocker: risk of severe AV block and cardiac arrest.
Propranolol (non-selective beta-1+beta-2) and verapamil profoundly depress AV conduction and contractility. Propranolol adds beta-2 blockade (bronchospasm) to verapamil's depressant effect. The combination can cause complete AV block, sinus arrest, cardiovascular collapse, and death. Absolutely CONTRAINDICATED — no safe dose exists for this combination.
Non-selective beta-blocker + non-dihydropyridine CCB: severe AV block and cardiac arrest. CONTRAINDICATED — risk of death.
Both depress AV conduction and contractility. The combination can cause high-grade AV block and cardiac arrest.
DailyMed/FDA (NIH/NLM) — approved Propranolol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0d5ac315-df2b-4b3a-bc7e-ad04752865c4
Hydralazine plus propranolol is therapeutically useful (controls reflex tachycardia), but stopping propranolol exposes the tachycardia and increases cardiac workload.
Direct arterial vasodilation by hydralazine triggers reflex tachycardia blocked by propranolol.
Heart rate, angina, blood pressure.
Sudden palpitations, chest pain.
Propranolol withdrawal must be gradual; monitor pulse and ischemic symptoms.
DailyMed — Hydralazine Hydrochloride label, reflex tachycardia (co-administration with beta-blocker): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=47ad263b-ad3d-4f98-b0aa-d9e82ab6cb67
Beta-blocker + H2 blocker: inhibition of hepatic metabolism of propranolol.
Cimetidine inhibits multiple CYPs (1A2, 2D6, 3A4), reducing first-pass metabolism of propranolol. AUC may increase 3-5 fold. Use ranitidine or famotidine as alternatives (do not significantly inhibit CYP).
Beta-blocker + H2 blocker: cimetidine inhibits CYP, increasing propranolol levels. Risk of excessive bradycardia.
Cimetidine inhibits CYP, increasing propranolol plasma levels. Risk of excessive bradycardia and hypotension.
DailyMed/FDA (NIH/NLM) — approved Propranolol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0d5ac315-df2b-4b3a-bc7e-ad04752865c4
Non-selective propranolol blocks hepatic β2 glycogenolysis and masks the warning symptoms of insulin-induced hypoglycaemia, potentially worsening and prolonging episodes.
Hepatic β2 blockade reduces compensatory glycogenolysis; cardiac β1 blockade removes the tachycardia warning (Prontuário 8.4.1; insulin label: agents increasing hypoglycaemia risk).
Capillary glucose, neurological status, sweating.
Sudden confusion, strange behaviour, loss of consciousness.
Monitor capillary glucose; prefer a cardioselective beta-blocker (metoprolol/bisoprolol) if needed; teach recognition of hypoglycaemia "without tachycardia".
DailyMed — Humulin R (regular insulin) and Inderal (propranolol) labels, Drug Interactions: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f6edd793-440b-40c2-96b5-c16133b7a921; INFARMED Prontuário Terapêutico (11th ed., 2012), 8.4.1.
Non-selective propranolol blocks hepatic glycogenolysis and masks the hypoglycaemia symptoms of the NPH insulin peak, especially overnight.
Hepatic β2 blockade prolongs and worsens hypoglycaemic episodes; β1 blockade removes the tachycardia warning (Prontuário 8.4.1; NPH label).
Overnight glucose, neurological status, sweating.
Morning confusion, headache, profuse night sweats.
Prefer a cardioselective beta-blocker; overnight glucose; consider NPH dose reduction if recurrent episodes.
DailyMed — Humulin N (NPH) and Inderal (propranolol) labels: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f6edd793-440b-40c2-96b5-c16133b7a921; INFARMED Prontuário Terapêutico (11th ed., 2012), 8.4.1.
Propranolol blocks both β1 and β2 and antagonises the inotropic effect of dobutamine more markedly, with a risk of loss of inotropic support, peripheral vasoconstriction and paradoxical hypertension.
Besides reversing the β1 (inotropic) effect, β2 blockade removes beta-2-mediated vasodilation, leaving dobutamine alpha effects unopposed — the result is peripheral vasoconstriction with increased vascular resistance and blood pressure (propranolol label: interaction with sympathomimetic amines).
Invasive blood pressure, cardiac index and vascular resistance, continuous ECG, lactate, peripheral perfusion.
Hypotension with cold extremities, paradoxical hypertension, oliguria, arrhythmias.
Avoid the combination in patients dependent on the inotrope; if the beta-blocker is indispensable, use the least negative chronotropic/inotropic option and monitor invasively; consider an inodilator as an alternative.
Dobutamine label (Pfizer labeling): https://labeling.pfizer.com/ShowLabeling.aspx?id=16395; EMC-UK — Dobutamine 5 mg/ml solution for infusion, SmPC 4.5: https://www.medicines.org.uk/emc/product/6462/smpc; INFARMED Prontuário Terapêutico (11th ed., 2012), Cardiotonics 3.1 (sympathomimetic amines require monitoring).
Food increases propranolol bioavailability (~70%), but no adjustment is needed if intake is consistent — routine is what matters.
Always take it the same way (with or without food) to keep the effect stable.
Prontuário 7.3 (propranolol — bioavailability ↑ with food); DailyMed Inderal.
CONTRAINDICATED in bronchial asthma — beta-2 blockade causes severe bronchospasm.
CONTRAINDICATED in any form of asthma or severe COPD.
DailyMed/FDA (NIH/NLM) — approved Propranolol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0d5ac315-df2b-4b3a-bc7e-ad04752865c4
Masks the adrenergic symptoms of hypoglycaemia (tachycardia, tremor).
Monitor blood glucose frequently. Prefer cardioselective beta-blocker.
DailyMed/FDA (NIH/NLM) — approved Propranolol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0d5ac315-df2b-4b3a-bc7e-ad04752865c4
Use only if benefit justifies risk. May cause neonatal bradycardia, hypoglycaemia, and respiratory distress.
Avoid in 3rd trimester if possible.
Excreted in breast milk in low concentrations. Generally compatible.
Monitor neonate for bradycardia, hypoglycaemia, and respiratory distress.
DailyMed/FDA (NIH/NLM) — approved Propranolol label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0d5ac315-df2b-4b3a-bc7e-ad04752865c4
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Non-selective lipophilic beta-blocker (β1+β2) that crosses the blood-brain barrier. Membrane-stabilising activity (local anaesthetic effect).
Non-selectively blocks beta-1 and beta-2 receptors, reducing heart rate, contractility, AV conduction, and causing bronchospasm (via beta-2).
Oral bioavailability: ~25% (extensive first-pass metabolism). Food increases absorption. Tmax: 1-2 hours.
Extensively metabolised by CYP2D6 and CYP1A2. Inhibited by fluoxetine, cimetidine. Induced by rifampicin. Genetic polymorphism.
3-6 hours. Elimination: ~90% urine (metabolites), <1% unchanged. Adjust in hepatic impairment.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
