Propranolol

Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class. It is used to treat high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance anxiety, and essential tremors, as well to prevent migraine headaches, and to prevent further heart problems in those with angina or previous heart attacks. It can be taken by mouth or by injection into a vein. The formulation that is taken by mouth comes in short-acting and long-acting versions. Propranolol appears in the blood after 30 minutes and has a maximum effect between 60 and 90 minutes when taken by mouth.

Common side effects include nausea, abdominal pain, and constipation. It should not be used in those with an already slow heart rate and most of those with heart failure. Quickly stopping the medication in those with coronary artery disease may worsen symptoms. It may worsen the symptoms of asthma. Caution is recommended in those with liver or kidney problems. Propranolol may cause harmful effects for the baby if taken during pregnancy. Its use during breastfeeding is probably safe, but the baby should be monitored for side effects. It is a non-selective beta blocker which works by blocking β-adrenergic receptors.

Propranolol was patented in 1962 and approved for medical use in 1964. It is on the World Health Organization's List of Essential Medicines. Propranolol is available as a generic medication. In 2019, it was the 82nd most commonly prescribed medication in the United States, with more than 9 million prescriptions.

Propranolol

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 cardiomyopathy
While 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. In one small study individuals given propranolol immediately after trauma experienced fewer stress-related symptoms and lower rates of PTSD than respective control groups who did not receive the drug. Due to the fact that memories and their emotional content are reconsolidated in the hours after they are recalled/re-experienced, propranolol can also diminish the emotional impact of already formed memories; for this reason, it is also being studied in the treatment of specific phobias, such as arachnophobia, dental fear, and social phobia.

Ethical and legal questions have been raised surrounding the use of propranolol-based medications for use as a "memory damper", including: altering memory-recalled evidence during an investigation, modifying behavioral response to past (albeit traumatic) experiences, the regulation of these drugs, and others. However, Hall and Carter have argued that many such objections are "based on wildly exaggerated and unrealistic scenarios that ignore the limited action of propranolol in affecting memory, underplay the debilitating impact that PTSD has on those who suffer from it, and fail to acknowledge the extent to which drugs like alcohol are already used for this purpose."

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