Ephedrine

Ephedrine is a central nervous system (CNS) stimulant and sympathomimetic agent that is often used to prevent low blood pressure during anesthesia.^[11] It has also been used for asthma, narcolepsy, and obesity but is not the preferred treatment.^[11] It is of unclear benefit in nasal congestion.^[11] It can be taken by mouth or by injection into a muscle, vein, or just under the skin.^[11] Onset with intravenous use is fast, while injection into a muscle can take 20 minutes, and by mouth can take an hour for effect.^[11] When given by injection, it lasts about an hour, and when taken by mouth, it can last up to four hours.^[11]

Common side effects include trouble sleeping, anxiety, headache, hallucinations, high blood pressure, fast heart rate, loss of appetite, and urinary retention.^[11] Serious side effects include stroke and heart attack.^[11] While probably safe in pregnancy, its use in this population is poorly studied.^[12][13] Use during breastfeeding is not recommended.^[13] Ephedrine works by inducing the release of norepinephrine and hence indirectly activating the α- and β-adrenergic receptors.^[11] Chemically, ephedrine is a substituted amphetamine and is the (1R,2S)-enantiomer of β-hydroxy-N-methylamphetamine.^[14]

Ephedrine was first isolated in 1885 and came into commercial use in 1926.^[15][16] It is on the World Health Organization's List of Essential Medicines.^[17] It is available as a generic medication.^[11] It can normally be found in plants of the Ephedra genus.^[11][18] Over-the-counter dietary supplements containing ephedrine are illegal in the United States,^[11] with the exception of those used in traditional Chinese medicine, where its presence is noted by má huáng.^[11][18]