Ephedrine
A CNS stimulant used for anesthesia and historically for asthma.
Ephedrine is a central nervous system (CNS) stimulant and sympathomimetic agent used to prevent low blood pressure during anesthesia. It has also been employed for asthma, narcolepsy, and obesity, though it is not the preferred treatment for these conditions.
- field
- Pharmacology, Medicine
- class
- CNS stimulant, sympathomimetic amine
- known_for
- Preventing low blood pressure during anesthesia; bronchodilator; weight loss agent
Lore & Background
Ephedrine works by inducing the release of norepinephrine, indirectly activating α- and β-adrenergic receptors. Chemically, it is a substituted amphetamine and the (1R,2S)-enantiomer of β-hydroxy-N-methylamphetamine. It can be taken by mouth or by injection into a muscle, vein, or just under the skin. Onset with intravenous use is fast, while injection into a muscle can take 20 minutes, and by mouth can take an hour for effect. When given by injection, it lasts about an hour; when taken by mouth, it can last up to four hours.
Reader's Guide
Ephedrine's significance lies in its role as a non-catecholamine sympathomimetic with cardiovascular effects similar to adrenaline, increasing blood pressure, heart rate, and contractility. It is a bronchodilator and has been used to decrease motion sickness and the sedating effects of other medications. However, its long-term effects are unknown. Ephedrine is available as a prescription intravenous solution and over-the-counter as oral tablets and nasal spray. Over-the-counter dietary supplements containing ephedrine are illegal in the United States, except in traditional Chinese medicine (má huáng). Common side effects include trouble sleeping, anxiety, headache, hallucinations, high blood pressure, fast heart rate, loss of appetite, and urinary retention; serious side effects include stroke and heart attack. Contraindications include use with certain antidepressants and monoamine oxidase inhibitors, as well as conditions like closed-angle glaucoma and cardiovascular disease.
Did You Know?
- It is on the World Health Organization's List of Essential Medicines.
- Over-the-counter dietary supplements containing ephedrine are illegal in the United States, except in traditional Chinese medicine (má huáng).
- The elimination half-life of ephedrine is 6 hours, and its duration of action orally is 2 to 4 hours.
Frequently Asked Questions
What are Ephedrine's powers or primary role?
Its signature role is preventing dangerously low blood pressure during surgical anesthesia, acting as a pressor agent. It also functions as a bronchodilator, which historically made it useful for asthma, narcolepsy, and obesity management.
How does Ephedrine's story end?
Ephedrine's story doesn't end so much as shift—while it is no longer the preferred treatment for asthma or weight loss, it remains a standard-of-care agent in anesthetic practice worldwide. It continues to be dispensed as a generic drug and stays on the WHO essential-medicines list.
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