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Bedside Snapshot

Propranolol is a nonselective beta-blocker (beta-1 and beta-2) used IV mostly for short-term control of supraventricular tachyarrhythmias and hyperadrenergic states (e.g., thyrotoxic tachycardia) in monitored settings.

  • Characteristics: Lipophilic, crosses the blood-brain barrier, and has no alpha-blocking activity. Compared with labetalol or esmolol, propranolol is less commonly chosen for hypertensive emergencies but is still useful for rate control in SVT/AF or thyrotoxicosis when IV beta-blockade is needed.
  • Typical adult IV dosing: 1 mg IV over at least 1 minute; may repeat every 2 minutes to a total of 3 mg. Once effect achieved (or 3 mg given), no further IV propranolol should be given for at least 4 hours.
  • Onset (IV): Within minutes; distribution half-life ~5–10 minutes. Duration of clinically relevant beta-blockade is usually 2–4 hours after a small bolus; elimination half-life ~2–6 hours.
  • Oral use: Widely used for chronic indications (angina, post-MI, migraine prophylaxis, portal hypertension/varices, essential tremor, anxiety). In the ED/ICU, IV use requires continuous ECG and BP monitoring.
Brand & Generic Names
  • Generic Name: Propranolol hydrochloride
  • Brand Names: Inderal, Inderal LA, various generics; IV propranolol 1 mg/mL vials/ampules
Medication Class

Nonselective beta-adrenergic blocker (beta-1 and beta-2); no intrinsic sympathomimetic activity

Pharmacology

Mechanism of Action:

  • Competitively blocks beta-1 and beta-2 adrenergic receptors, reducing chronotropy, inotropy, and AV nodal conduction (beta-1) and attenuating beta-2 mediated vasodilation and bronchodilation
  • Reduces heart rate, myocardial contractility, and myocardial oxygen demand; prolongs AV nodal conduction time, which slows ventricular response in supraventricular tachyarrhythmias
  • Lack of intrinsic sympathomimetic activity means a relatively pure beta-blocking effect; no alpha blockade, so BP reduction is via decreased cardiac output and suppression of renin rather than vasodilation
  • Lipophilicity allows CNS penetration, which may contribute to effects on tremor, anxiety, and migraine, but also to CNS adverse effects (fatigue, depression, vivid dreams) with chronic use

Pharmacokinetics:

  • IV concentration: Usually 1 mg/mL propranolol hydrochloride solution
  • Onset (IV): Effects on heart rate and BP occur within minutes of administration
  • Distribution: Highly lipophilic with extensive tissue binding; distribution half-life ~5–10 minutes. Protein binding ~90–95%. Volume of distribution ~4–5 L/kg
  • Metabolism: Extensive first-pass and systemic hepatic metabolism to multiple inactive and active metabolites
  • Elimination half-life: Approximately 2–6 hours after IV dosing in adults with normal hepatic function; prolonged in hepatic impairment or cirrhosis
  • Elimination: Primarily via hepatic metabolism with urinary excretion of metabolites; dose adjustments are mainly guided by clinical response and hepatic function rather than renal function
Indications
  • Supraventricular tachycardia (SVT): Short-term treatment, including atrial flutter and certain atrial tachyarrhythmias, particularly when other first-line agents are ineffective or contraindicated
  • Atrial fibrillation/flutter rate control: Usually when other AV nodal blockers are unsuitable or as adjunct therapy
  • Thyrotoxic crisis/thyroid storm: Adjunctive therapy to control tachycardia and reduce peripheral conversion of T4 to T3 (though oral or NG dosing is often preferred if feasible)
  • Peri-anesthesia/perioperative: Control of hyperadrenergic tachycardia and hypertension in selected patients
  • Pediatric arrhythmias: Specialist-driven, often weight-based dosing (beyond scope of this adult-focused reference)
Dosing & Administration

Available Forms:

  • IV injection: 1 mg/mL in 1 mL ampules or vials for slow IV administration or dilution
  • Oral immediate-release tablets: commonly 10 mg, 20 mg, 40 mg, 60 mg, 80 mg
  • Oral extended-release capsules (LA/XL): commonly 60 mg, 80 mg, 120 mg, 160 mg

Standard Adult Dosing:

Indication Dose & Route Frequency / Titration Notes
Supraventricular tachycardia / atrial arrhythmias (acute rate control) 1 mg IV over at least 1 minute May repeat q2 minutes up to total 3 mg After 3 mg or adequate effect, hold further IV doses for at least 4 hours
Thyrotoxic crisis (when IV route needed) 1 mg IV over 1 minute Repeat q2 minutes up to 3 mg, then transition to oral/NG dosing (e.g., 20–40 mg PO q6h) as tolerated Use with extreme caution in decompensated HF or hypotension; esmolol is often preferred
Perioperative hyperadrenergic tachycardia (selected cases) 0.5–1 mg IV over 1 minute Repeat q2–5 minutes to max total 3–5 mg as needed Use only with continuous ECG/BP monitoring and resuscitation capabilities
Continuous infusion (less common; specialist use) 2–3 mg/hour IV infusion Titrate to heart rate/BP targets More often, short boluses are used rather than continuous infusion
Oral step-down for arrhythmias 10–30 mg PO 3–4 times daily (IR) Titrate to 40–160 mg/day for arrhythmia control Adjust dose based on HR/BP, comorbidities, and chronic indications
Administration Notes: IV propranolol should be given slowly (not exceeding 1 mg/min) with continuous ECG and blood pressure monitoring. Allow time after each dose (at least 2 minutes) to assess full effect before redosing, especially in patients with reduced cardiac output or slow circulation.
Contraindications

Absolute Contraindications:

  • Cardiogenic shock or overt decompensated heart failure (unless tachyarrhythmia-driven and managed by specialists)
  • Sinus bradycardia, greater than first-degree heart block (unless paced), or sick sinus syndrome
  • Bronchial asthma or significant bronchospastic disease
  • Hypersensitivity to propranolol or other beta-blockers

Major Precautions:

  • COPD or reactive airway disease: Even small doses can provoke bronchospasm in susceptible patients
  • Diabetes mellitus: May mask hypoglycemic symptoms (tachycardia, tremor) and blunt counter-regulatory responses
  • Peripheral vascular disease and Raynaud phenomenon: Can exacerbate vasospasm and ischemia
  • Depression and psychiatric disorders: CNS penetration may worsen mood symptoms in some patients
  • Hepatic impairment: Reduced clearance and prolonged half-life; titrate doses cautiously
Bronchospasm Risk: Because propranolol is nonselective (blocks beta-2 receptors), it can cause severe bronchospasm in patients with asthma or reactive airway disease. Avoid use in these patients.
Adverse Effects

Common:

  • Bradycardia, hypotension, fatigue
  • Dizziness, lightheadedness
  • Cold extremities, exercise intolerance
  • Gastrointestinal upset (nausea, diarrhea)

Serious:

  • Symptomatic bradycardia, high-grade AV block, asystole
  • Acute decompensated heart failure or cardiogenic shock
  • Bronchospasm, especially in asthma
  • Severe hypotension
  • Masking of hypoglycemia and prolonged hypoglycemic episodes in insulin-treated diabetics
Special Populations

Hepatic Impairment:

  • Reduced clearance and prolonged half-life in hepatic impairment or cirrhosis
  • Titrate doses cautiously and monitor closely for excessive beta-blockade
  • Consider lower initial doses and longer intervals between doses

Renal Impairment:

  • Dose adjustments are mainly guided by clinical response and hepatic function rather than renal function
  • Monitor carefully as these patients may have multiple comorbidities

Diabetes:

  • May mask hypoglycemic symptoms (tachycardia, tremor) and blunt counter-regulatory responses
  • Use with caution and ensure close blood glucose monitoring, particularly in insulin-treated patients

Oral to IV Conversion:

  • When transitioning from IV to oral propranolol, remember that oral bioavailability is lower and variable due to first-pass metabolism
  • Start with modest oral doses and titrate to effect
Monitoring

Clinical Monitoring:

  • Continuous ECG and blood pressure monitoring during IV dosing and in unstable patients
  • Heart rate and rhythm for bradycardia, AV block, or new arrhythmias
  • Signs and symptoms of heart failure (dyspnea, edema, rising BNP or lactate)
  • Respiratory status, especially in patients with any bronchospastic history

Laboratory Monitoring:

  • Blood glucose in diabetics receiving IV beta-blockade, particularly if insulin or sulfonylureas are in use
  • Liver function tests if prolonged or high-dose therapy is anticipated
Clinical Pearls
Not First-Line for Hypertensive Emergencies: Because propranolol is nonselective and lacks alpha blockade, it is not the first-line agent for hypertensive emergencies; reserve IV use for rate control in carefully selected arrhythmia or thyrotoxic cases.
Modern Alternatives: In many modern ICUs, esmolol (short-acting, beta-1 selective) or metoprolol are preferred for titratable beta-blockade; propranolol remains useful when its lipophilicity or T4-to-T3 conversion effects are desired.
Slow Administration Critical: Give IV propranolol slowly and in small increments with time to see effect; overshooting can produce profound bradycardia and hypotension that are hard to quickly reverse.
Chronic Indications: For chronic indications (migraine, portal hypertension, tremor), oral dosing strategies dominate; this reference focuses on short-term IV use in monitored settings.
Thyrotoxicosis Benefits: In thyrotoxicosis, oral or nasogastric propranolol (20–40 mg every 6 hours) is often preferred when feasible, due to more sustained control and impact on T4-to-T3 conversion.
First-Pass Metabolism: When transitioning from IV to oral propranolol, remember that oral bioavailability is lower and variable due to first-pass metabolism; start with modest oral doses and titrate to effect.
References
  • 1. Drugs.com. (2025). Propranolol dosage guide with precautions. https://www.drugs.com/dosage/propranolol.html
  • 2. U.S. Food and Drug Administration. (2024). Propranolol hydrochloride injection prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/016418s090lbl.pdf
  • 3. Shahrokhi, M., & Hamburg, N. M. (2023). Propranolol. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557801/
  • 4. DrugBank Online. (2024). Propranolol (DB00571). https://go.drugbank.com/drugs/DB00571
  • 5. Klein, I., & Ojamaa, K. (2001). Thyrotoxicosis and the heart. Endocrinology and Metabolism Clinics of North America, 30(2), 517–540. https://doi.org/10.1016/S0889-8529(05)70197-6
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