Wutou Tang: A Classic Pain-Relieving Formula from the Jin Gui Yao Lue
Wutou Tang (Aconitum Decoction) comes from the Jin Gui Yao Lue (Essential Prescriptions of the Golden Coffer), a classic formula collected by the Han-dynasty physician Zhang Zhongjing. Its composition is: Mahuang (Ephedrae Herba), Baishao (Paeoniae Alba Radix), Huangqi (Astragali Radix), and Zhigancao (Glycyrrhizae Radix preparata), each 3 liang (some scholars hold that one Han-dynasty liang equals about 15 g today, but for safety it is recommended to convert 1 liang as 3 g); Chuanwu (Aconiti Radix) 2 liang (6 g), decocted in 400 ml of honey down to 200 ml, after which the Aconitum is removed (diabetic patients may omit the honey).
Except for the Chuanwu, decoct the five herbs in 600 ml of water down to 200 ml and strain. Combine this decoction with the honey in which the Chuanwu was simmered, and decoct once more until about 300 ml remains. First take 150 ml; if pain is not relieved after dosing, take the remaining 150 ml as well.
Because this formula relieves pain relatively quickly, effect usually appears within ten-plus minutes; if no analgesic effect appears after half an hour, the dose should be increased. Note that it is not advisable to rashly dose by the Han-dynasty conversion of 15 g per liang. Both the Mahuang and the Wutou in this formula carry considerable side effects; although the aconitine in Wutou is highly toxic, in practice, when Mahuang is used at high doses, its adverse effects can be even greater than those of aconitine.
At 45 g, Mahuang can raise blood pressure and cause tachycardia, and in severe cases can even cause sudden death. Patients with a prior history of hypertension or heart disease must be cautious when using this formula. I have personally tested the herb; at doses above 30 g, my heart felt very distressed. If one has taken too much Mahuang, drink more water to accelerate its metabolism; the side effects gradually lessen as urine output increases.
Wutou Tang warms yang and boosts qi, disperses cold and expels dampness. It is indicated for cold-dampness lodged in the joints with obstruction of the channels, causing severe joint pain and inability to flex or extend. In the formula, Baishao combined with Zhigancao forms Shaoyao Gancao Tang, which treats spasmodic pain and impaired joint flexion. Huangqi supplements qi; Mahuang warms yang and disperses cold; Chuanwu (Aconitum) unblocks the channels and stops pain.
The rationale of this formula is not hard to grasp, and its clinical application is indeed effective. Wutou Tang is widely used for chronic low-back and leg pain, vasculitic pain, sciatica, cancer pain, rheumatic pain, trigeminal neuralgia, uterine prolapse, and other conditions. Using Wutou Tang as the base and modifying the herbs according to the patient’s condition usually yields some analgesic effect.
Because the safety of this formula is not high, self-administration by patients is not recommended; use it only under a doctor’s guidance.