Propranolol
Propranolol is a non-selective beta-adrenergic antagonist and naphthalene derivative first approved by the FDA in 1967.1 It is prescribed for a broad range of conditions including hypertension, essential tremor, migraine prophylaxis, and anxiety.2 As a racemic mixture, its S(-)-enantiomer demonstrates roughly 100 times greater binding affinity for beta-adrenergic receptors than its counterpart, accounting for most of its pharmacological activity.1
Contents
Dosage & Duration
Dosage
Duration
Subjective Effects
Propranolol produces little in the way of a classical psychoactive experience at therapeutic doses. Its most noticeable subjective effect is an absence of the physical symptoms of anxiety — a slowed, steadier heartbeat and reduced trembling — which users often experience as a subtle bodily calm rather than a distinct headspace. Overdose presents a markedly different picture, with restlessness, euphoria, and insomnia reported alongside dangerous drops in blood pressure.
Physical
Physical effects center on cardiovascular dampening, including a slowed heart rate, lowered blood pressure, and reduced tremor. Mild fatigue and lightheadedness may accompany these effects.
Cardiovascular
Cognitive
The headspace remains largely clear and unaltered. Anxiety relief is generally attributed to the suppression of anxiety's physical manifestations rather than to direct cognitive sedation.
Reagent Testing
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Pharmacology
Pharmacodynamics
Propranolol is a competitive, nonselective β-adrenergic receptor antagonist that blocks β1, β2, and β3 receptors with little intrinsic sympathomimetic activity, inhibiting the actions of epinephrine and norepinephrine.3 It is administered as a racemic mixture in which the S(−)-enantiomer has approximately 100 times the binding affinity for beta-adrenergic receptors.3 Propranolol also blocks voltage-gated sodium channels, a property underlying its membrane-stabilizing effects, although this occurs primarily at high blood concentrations.43 Additionally, it acts as a weak antagonist at serotonin 5-HT1A, 5-HT1B, and 5-HT2B receptors and shows very weak inhibitory effects on the norepinephrine transporter.
Pharmacokinetics
Propranolol is rapidly and completely absorbed following oral administration, with peak plasma levels reached in approximately 1 to 4 hours.3 Despite complete absorption, oral bioavailability is only approximately 25%.3 Food increases bioavailability without affecting time to peak levels.3 Propranolol is highly lipophilic and achieves high concentrations in the brain.3 It is metabolized through aromatic hydroxylation (mainly 4-hydroxylation), N-dealkylation, side-chain oxidation, and glucuronidation, with approximately 42% of a dose undergoing ring oxidation and 17% undergoing glucuronidation.3 The plasma half-life is approximately 3 to 6 hours, with an elimination half-life reported at approximately 8 hours.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Harm Potential
Addiction & Dependence
Psychological
Extremely LowPropranolol carries lower risks for addiction or abuse compared to benzodiazepines.5 No significant psychological dependence or compulsive use patterns are documented.5
Physical
LowClassic physical dependence does not develop; however, abrupt discontinuation in patients with cardiovascular conditions may cause serious rebound effects including exacerbation of angina or myocardial infarction.1 Gradual tapering is recommended.1
Toxicity
Overdose can cause severe bradycardia, hypotension, and potentially fatal cardiac arrest;1 chronic therapeutic use at typical doses has been associated with increased risk of type 2 diabetes in some populations.
May worsen symptoms of asthma and cause bronchospasm in patients with reactive airway disease; this risk is present even at therapeutic doses in susceptible individuals.1
May mask signs and symptoms of hypoglycemia in diabetic patients, potentially allowing dangerous blood glucose levels to go unrecognized.1
Seizure Risk
Seizures are associated with propranolol overdose, particularly hypoglycemic seizures.67 This risk is primarily an overdose concern rather than occurring at therapeutic doses.
History & Culture
Legality
By Country
References
Source Pages
Citations
- (1 August 2024). Inderal LA- propranolol hydrochloride capsule, extended release. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=35d28979-36b1-4630-b85e-a44e0a44373412345678910111213
- (n.d.). PROPRANOLOL HYDROCHLORIDE tablets — DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b94dcec7-7633-4a33-9cea-48161adeaf931
- (n.d.). Propranolol Hydrochloride Tablet — DailyMed (setid 23af21f4-cba8-485b-943c-1163b3910ab5). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=23af21f4-cba8-485b-943c-1163b3910ab512345678
- (n.d.). Propranolol Blocks Cardiac and Neuronal Voltage-Gated Sodium Channels — PMC3153018. https://pmc.ncbi.nlm.nih.gov/articles/PMC3153018/1
- Chandrasekaran V, Subramanian K, & Muthuramalingam A. (2020). Propranolol Abuse: A Case Report on the Harmful Consequence of Over-the-Counter Medications. Indian Journal of Psychological Medicine. https://doi.org/10.1177/025371762093698512
- (n.d.). Propranolol (PIM 441). INCHEM – International Programme on Chemical Safety. https://inchem.org/documents/pims/pharm/pim441.htm1
- Sharifpour A, Sadeghi M, Zakariaei Z, & Soleymani M. (2022). Seizures and Irreversible Cardiogenic Shock Following Propranolol Poisoning: Report of 2 Cases and Literature Review. Clinical Medicine Insights: Case Reports. https://doi.org/10.1177/117954762211269811
- (1988). Nobel Prize in Physiology or Medicine 1988 – Sir James W. Black Facts. https://www.nobelprize.org/prizes/medicine/1988/black/facts/1
- (2006). Putting Theory into Practice: James Black, Receptor Theory and the Development of the Beta-Blockers at ICI, 1958–1978. https://pmc.ncbi.nlm.nih.gov/articles/PMC1369014/1234
- (2019). Propranolol: A 50-Year Historical Perspective. https://pmc.ncbi.nlm.nih.gov/articles/PMC6327687/12
- (2025). Proposal for the Addition of Amitriptyline to the WHO Model List of Essential Medicines for the Prophylaxis of Migraine (2025 WHO Expert Committee submission). World Health Organization. https://cdn.who.int/media/docs/default-source/2025-eml-expert-committee/new-indications-for-existing-medicines/i.2_amitriptyline-migraine.pdf1
- (2017). The 2015 Musicians' Health Survey Results | Senza Sordino (ICSOM). https://www.icsom.org/senzasordino/2017/06/the-2015-musicians-health-survey-results/1
- (2008). N Korean shooter stripped of medals. https://www.aljazeera.com/news/2008/8/15/n-korean-shooter-stripped-of-medals1
- (n.d.). Health Canada Drug Product Database — DETENSOL TAB 10MG (DIN 00511560). Health Canada. https://health-products.canada.ca/dpd-bdpp/info?lang=eng&code=39501
- (n.d.). Anlage 1 AMVV — Arzneimittelverschreibungsverordnung (German Prescription Drug Regulation). Bundesministerium der Justiz / Gesetze im Internet (Germany). https://www.gesetze-im-internet.de/amvv/anlage_1.html1
Further Reading
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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