Mahwang (Ephedrine) in Gongbihwan: Action and Safe Administration

Many people stop at '마황' (Mahwang) when reading the names of medicinal herbs on the back of their prescribed Korean medicine packet. A search often brings up the word ephedrine. The packet has already been received, but there's no clear information anywhere on when to take it, whether coffee is allowed, or for how many days to take it and when to take a break.

Mahwang is a medicinal herb that has been used for a long time, and at the same time, its specifications are precisely defined. The pharmacopoeia specifies which part of which plant to use and how much of its components it should contain. There is also a basis for practical administration. Knowing how long the components stay in the body determines when to take the medicine. This article is about Mahwang itself as a medicinal herb and its daily management after receiving a prescription.

This is What the Pharmacopoeia Regulates for Mahwang

The 「대한민국약전」(the Korean Pharmacopoeia) specifies the origin of Mahwang (Ephedra Herb) as three species: Ephedra sinica, Ephedra intermedia, and Ephedra equisetina. The part used is the herbaceous stem of the Ephedra plant, meaning a grass-like stem. If more than 5.0% of woody stems, which are hardened like wood, are mixed in, it does not meet the specifications.

Content standards are also set. The pharmacopoeia requires total alkaloids (ephedrine and pseudoephedrine) of 0.7% or more on a dry basis and specifies quantification by liquid chromatography at a wavelength of 210 nm. Purity tests list lead 5 ppm, arsenic 3 ppm, mercury 0.2 ppm, cadmium 0.3 ppm or less, residual pesticides such as total DDT and dieldrin, and sulfur dioxide 30 ppm or less. These numbers represent the actual content of what is called a 'standardized herbal medicine'.

Ephedrine Indirectly Stimulates the Sympathetic Nervous System

Professor Kim Ho-cheol of the Department of Herbalogy, College of Korean Medicine, Kyung Hee University, describes ephedrine as an indirect sympathomimetic agent in his series in 『한의신문』 (Korean Medicine Newspaper). This means that instead of the component directly binding to receptors, it exerts its action by releasing norepinephrine from nerve endings. As a result, blood vessels constrict, blood pressure and heart rate increase, and bronchial smooth muscles relax. Ephedrine has been used as an asthma treatment, decongestant, and for treating hypotension during surgery due to the same mechanism of action.

The reason for increased metabolism also stems from this. The Mahwang clinical practice guidelines in the 2007 『한방비만학회지』 (Journal of Korean Medicine for Obesity Research) classify ephedrine as a thermogenic metabolic enhancer, stating that it increases 24-hour energy expenditure along with increased cardiac output. Central stimulating effects that promote dopamine and norepinephrine secretion are also described. However, the same paragraph clearly states that repeated use leads to a sharp decrease in response and the development of tolerance.

There is one more thing. The total alkaloid content of Mahwang varies between 0.5% and 2.5%, and the proportion of ephedrine within that also varies from 30% to 90% depending on the harvest time and growth environment. Even if the same weight is used, the actual exposure amount differs. This is why a Korean medicine doctor must determine the prescription.

Originally, it was a Medicine for Inducing Sweat and Relieving Dyspnea

In Korean medicine, Mahwang's role was not weight management. The same clinical guidelines describe Mahwang's taste and nature as pungent and warm [辛溫], and its effects are summarized as inducing diaphoresis to release the exterior, diffusing lung qi to relieve asthma, promoting diuresis to reduce swelling, and warming channels to unblock collaterals. This means inducing sweat to expel external pathogens, expanding lung qi to alleviate shortness of breath, and promoting water circulation to reduce swelling. It was a medicinal herb used for colds, coughs, and edema.

The tradition of dosage also remains. The guidelines reviewed prescriptions from 『동의보감』 (Donguibogam) and found that the most common daily dosage of Mahwang for internal medicine was 8-16 g, accounting for 58.2% of all cases, with records of up to 24 g being used in relatively urgent situations. In Sasang constitutional medicine, it is classified as a Taeeumin (Greater Yin person) medicine, and it was believed that if used inappropriately for one's constitution, reactions such as insomnia, dry mouth, and excessive sweating could occur.

The use of Mahwang in obesity prescriptions is a method that utilizes the metabolic and central stimulating effects associated with its traditional actions. As its original use and purpose differ, it is considered a medicinal herb for which dosage and duration should be more narrowly defined.

Processing and Decoction Alter Exposure

The practice of processing Mahwang instead of using it raw has a long history. A representative method is honey-frying (蜜炙, milja). The purpose is to mitigate its diaphoretic properties. This was because excessive sweating was believed to harm body fluids and be particularly burdensome for the elderly and infirm.

An animal study published in 『Evidence-Based Complementary and Alternative Medicine』 in 2017 confirmed this practice at the component level. When comparing oral administration of raw Mahwang extract and honey-fried Mahwang extract, the blood exposure (AUC) of ephedrine decreased from 10,862 to 5,806 μg/L·h, and pseudoephedrine decreased from 7,115 to 3,145 μg/L·h (p<0.01 for each). This indicates reduced absorption. While rat experiments cannot be directly extrapolated to humans, the direction that processing alters component exposure is clear.

The decoction method is also a variable. According to research cited in the clinical guidelines, when decocting Mahwang, 90% of ephedrine is extracted into the decoction within 5 minutes of the water starting to boil. The amount of ephedrine in formula decoctions prepared with other medicinal herbs was 73-96% of that when Mahwang was decocted alone, and pre-decocting Mahwang increased the content by approximately 12%. This means that even if the g amount in the prescription is the same, the preparation process influences the exposure amount.

Jaimdang's Gongbihwan is also a prescription containing Mahwang, and it is a Korean medicine doctor's prescription drug whose administration is determined after consultation and prescription by a Korean medicine doctor. Preparation is carried out in an off-site decoction center in Paju, Gyeonggi Province, using standardized decoction with controlled temperature, time, and pressure. The indicator components of standardized medicinal herbs are quantified by HPLC, and each batch undergoes quality inspection and is tracked by lot number. The preparation process is detailed separately in [Off-site Decoction Centers and Herbal Medicine Quality](/en/journal/wonoe-tangjeon-quality).

When to Take It, and What to Adjust Alongside

The basis for administration timing is pharmacokinetics. Data summarized in the clinical guidelines show that ephedrine is almost completely absorbed in the digestive tract within 2-2.5 hours after oral administration, reaches peak blood concentration around 2.4 hours, and has a half-life of 6.1 hours. Most of it is excreted in the urine within 24 hours of administration.

If taken at six in the evening, calculations show that nearly half of it would still remain in the body by bedtime. The guidance to advance administration to morning and early afternoon stems from this, not from mere custom. It is generally advisable not to take the last dose of the day past mid-afternoon, and the exact timing should be determined with the prescribing Korean medicine doctor.

Caffeine must be considered separately. The guidelines state that concomitant use of caffeine and Mahwang increases both effects and side effects. Anhydrous caffeine from coffee, energy drinks, and supplements should be totaled on a daily basis and kept as far apart as possible from the administration time. Water should be consciously consumed in portions. As it is a diaphoretic herb, dry mouth and thirst are likely to follow.

Absorption conditions are also worth noting. The guidelines summarize that ephedrine is better absorbed under alkaline conditions, so its effects are strengthened if taken with dairy products, vegetables, fruits, nuts, or antacids, while acidic foods like meat and flour-based dishes accelerate its excretion. Athletes have one more thing to check: Mahwang and ephedrine are prohibited substances in many competitions.

Three types of records are sufficient: pulse measured while sitting in the morning, time of falling asleep and number of times waking up at night, and blood pressure. Having these numbers provides a basis for dosage adjustment at the next consultation. The reason for setting a period and including rest intervals is due to tolerance and cumulative exposure. The guidelines consider Mahwang's side effects to be related to dose-dependency with long-term use, individual constitution and sensitivity, daily dosage, and concomitant use with other sympathomimetic substances. The duration of administration and the timing of breaks are determined by the prescribing Korean medicine doctor.

Criteria for stopping should be agreed upon in advance. If palpitations or difficulty falling asleep persist for several days, do not reduce the dosage yourself; inform the Korean medicine clinic immediately. If neurological symptoms such as chest pain, fainting, severe headache, or weakness in one limb occur, the emergency room should be prioritized over contacting the Korean medicine clinic.

Daily Checks During Administration

• Measure your morning pulse for 1 minute while sitting — It must be measured at the same time and in the same posture for comparison. If days of distinctly higher pulse than usual persist, record it and report it.
• Note the time of your last dose — Check if days when you took it past mid-afternoon coincide with days you had difficulty falling asleep. If they overlap, adjusting the timing is the first step.
• Total the caffeine consumed that day — Count all coffee, tea, energy drinks, and supplements. Also note how many hours apart it was from your administration time.
• Count how much water you drank — Dry mouth and thirst are reactions that accompany diaphoretic action. Counting by cups is sufficient.

References

• Ministry of Food and Drug Safety, 「대한민국약전」(the Korean Pharmacopoeia) — Mahwang (麻黃) Ephedra Herb」
• Kim Ho-jun et al., 「비만치료 및 체중감량에서의 적절한 마황 사용에 대한 임상 진료지침 개발」(Development of Clinical Practice Guidelines for Appropriate Use of Mahwang in Obesity Treatment and Weight Loss), 『한방비만학회지』 (Journal of Korean Medicine for Obesity Research) 7(2), 2007
• Cheng Y et al., Comparative Pharmacokinetics and Bioavailability of Three Ephedrines in Rat after Oral Administration of Unprocessed and Honey-Fried Ephedra Extract, *Evidence-Based Complementary and Alternative Medicine*, 2017
• Kim Ho-cheol, 「과학으로 보는 한약 이야기 13 — 마황은 정말 땀을 내서 치료하는가?」(Korean Herbal Medicine Stories Through Science 13 — Does Mahwang Really Treat by Inducing Sweat?), 『한의신문』 (Korean Medicine Newspaper)
• Wang Q et al., Ephedrae Herba: A Review of Its Phytochemistry, Pharmacology, Clinical Application, and Alkaloid Toxicity, *Molecules* 28(2), 2023

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*This article is intended to explain information about Mahwang-containing Korean medicine and its administration management methods, and does not guarantee the diagnosis or therapeutic effects for specific diseases. Korean medicine, including Gongbihwan, is a prescription drug determined by a Korean medicine doctor's diagnosis and prescription regarding its administration, dosage, and duration, and reactions may vary by individual. If adverse reactions occur during administration, do not arbitrarily adjust the dosage; inform the prescribing Korean medicine clinic. If symptoms such as chest pain, fainting, or neurological symptoms occur, seek medical attention immediately without delay.*