Medical uses
Propranolol is used for treating various conditions, including:

Cardiovascular
Hypertension
Angina pectoris (with the exception of variant angina)
Myocardial infarction
Tachycardia (and other sympathetic nervous system symptoms, such as muscle tremor) associated with various conditions, including anxiety, panic, hyperthyroidism, and lithium therapy
Portal hypertension, to lower portal vein pressure
Prevention of esophageal variceal bleeding and ascites
Anxiety
Hypertrophic cardiomyopathyWhile once a first-line treatment for hypertension, the role for beta blockers was downgraded in June 2006 in the United Kingdom to fourth-line, as they do not perform as well as other drugs, particularly in the elderly, and evidence is increasing that the most frequently used beta blockers at usual doses carry an unacceptable risk of provoking type 2 diabetes.Propranolol is not recommended for the treatment of high blood pressure by the Eighth Joint National Committee (JNC 8) because a higher rate of the primary composite outcome of cardiovascular death, myocardial infarction, or stroke compared to an angiotensin receptor blocker was noted in one study. Psychiatric
Propranolol is occasionally used to treat performance anxiety, although evidence to support its use in any anxiety disorders is poor. Its benefits appear similar to benzodiazepines in panic disorder with potentially fewer side effects such as addiction. Some experimentation has been conducted in other psychiatric areas:
Post-traumatic stress disorder (PTSD) and specific phobias (see subsection below)
Aggressive behavior of patients with brain injuries
Treating the excessive drinking of fluids in psychogenic polydipsia

PTSD and phobias
Propranolol is being investigated as a potential treatment for PTSD. Propranolol works to inhibit the actions of norepinephrine, a neurotransmitter that enhances memory consolidation.
Coadministration with food appears to enhance bioavailability. Despite complete absorption, propranolol has a  variable bioavailability due to extensive first-pass metabolism. Hepatic impairment therefore increases its bioavailability. The main metabolite 4-hydroxypropranolol, with a longer half-life (5.2–7.5 hours) than the parent compound (3–4 hours), is also pharmacologically active. Most of the metabolites are excreted in the urine.Propranolol is a highly lipophilic drug achieving high concentrations in the brain. The duration of action of a single oral dose is longer than the half-life and may be up to 12 hours, if the single dose is high enough (e.g., 80 mg). Effective plasma concentrations are between 10 and 100 mg/L. Toxic levels are associated with plasma concentrations above 2000 mg/L. History
Scottish scientist James W. Black developed propranolol in the 1960s. It was the first beta-blocker effectively used in the treatment of coronary artery disease and hypertension. In 1988, Black was awarded the Nobel Prize in Medicine for this discovery. Propranolol was inspired by the early β-adrenergic antagonists dichloroisoprenaline and pronethalol. The key difference, which was carried through to essentially all subsequent beta blockers, was the inclusion of an oxymethylene group (-O-CH2-) between the aryl and ethanolamine moieties of pronethalol, greatly increasing the potency of the compound. This also apparently eliminated the carcinogenicity found with pronethalol in animal models. Newer, more cardio-selective beta blockers (such as bisoprolol, nebivolol, carvedilol, or metoprolol) are now used preferentially in the treatment of hypertension.