Kaidao San: An Empirical Formula for Esophageal Obstruction from Esophageal Cancer
Kaidao San (Way-Opening Powder) is an empirical TCM formula for treating esophageal obstruction caused by esophageal cancer. Its composition is: Pengsha (Borax, 硼砂) 60 g, Huoxiao (Nitre, 火硝) 30 g, Naosha (Sal Ammoniac, 硇砂) 6 g, Chenxiang (Aquilariae Lignum, 沉香) 9 g, Bingpian (Borneolum, 冰片) 9 g, Jinmengshi (Lapis Micae Aureus, 金礞石) 15 g. Grind the above together into a fine powder. Each time take 1 g, hold it in the mouth and swallow slowly, once per hour. Once the sticky froth is expectorated and the patient can take liquid food, change to once every 3 hours; stop after 2 consecutive days. There is also a version composed of Zhusha (Cinnabar), Naosha, Pengsha, Shishi shuang (persimmon frost), Ge fen (clam powder), Qingdai (Indigo naturalis), and white sugar, also named Kaidao San. All are used to treat the esophageal obstruction and inability to swallow in patients with esophageal cancer.
The Naosha, Bingpian, and Jinmengshi used in this formula all have certain toxicity, so they must not be used in large amounts or for long periods. This is a formula for temporary relief of inability to swallow; the name "Kaidao" (way-opening) indicates its main function. Once the patient can swallow, this formula should not be continued; instead, switch to other formulas, such as modified Canzhe Peiqi Tang (Ginseng-Ochre Qi-Rooting Decoction).
The herbs in this formula are not easy to gather at an ordinary pharmacy. For patients with first-time inability to swallow, I sometimes use a simpler method: just one herb, Xuanming fen (Mirabilitum purum) or Mangxiao (Natrii Sulfas), 1-3 g each time, held in the mouth to dissolve, to address the swallowing problem; in practice this also has some effect. If it is inconvenient to buy the herbs for Kaidao San, patients may try this simple method with Glauber's salt to relieve the problem.
The Naosha in Kaidao San is an ore drug with a certain therapeutic effect on esophageal cancer. Naosha is the crystal of sal ammoniac (chloride halide mineral) or an artificially prepared product. Traditional TCM holds that Naosha dissipates accumulation and softens hardness, decomposes necrosis and promotes tissue regeneration, expels phlegm, and promotes diuresis. It is mainly used for abdominal masses and accumulations, dysphagia and regurgitation, throat impediment and swelling, carbuncles and swellings, scrofula, corneal opacity, polyps, and warts.
But Naosha is corrosive, so prolonged use may cause peptic ulcers. Daily small-dose use of Naosha has a certain inhibitory effect on upper gastrointestinal tumors such as esophageal cancer, cardia cancer, and gastric cancer. However, if the patient develops acid regurgitation, heartburn, or stomach pain, it should be stopped or combined with other drugs that protect the gastrointestinal mucosa (such as Baiji, Bletilla striata).
The main component of Huoxiao (Nitre) is potassium nitrate. TCM holds that Huoxiao softens hardness and dissipates nodules, detoxifies and reduces swelling, promotes diuresis, and purges. But Huoxiao has a laxative side effect, so caution is needed; pregnant women should be forbidden from taking Chinese medicines containing Huoxiao.
Pengsha (Borax) is a borate mineral of the borax family. TCM holds that borax clears heat and resolves phlegm, detoxifies and prevents decay. Taken internally it treats phlegm-heat cough, dysphagia and accumulations, and fish-bone stuck in the throat; applied externally it treats sore throats, mouth and tongue ulcers, red eyes with pannus, pterygium, and genital ulcers. In addition, borax, like Bingpian in the formula, has a certain analgesic effect and can relieve the pain caused by esophageal obstruction.
Borax has certain hazards to the human body and may damage the digestive system, liver, kidneys, nervous system, and reproductive system, but it is relatively safe at low doses; still, it must not be used for long periods.
Chenxiang (Aquilaria) moves qi and relieves pain, warms the middle and stops vomiting, and anchors qi and calms wheezing. It can relieve stomach and abdominal distending pain, stop vomiting, improve wheezing, soothe gastrointestinal spasms, promote digestion, reduce breathlessness and pain, and also has antibacterial, blood-pressure-regulating, and nerve-relaxing effects. Bingpian and Chenxiang are used as a mutually reinforcing pair in this formula, mainly exerting an analgesic effect; Chenxiang also resolves stagnation and relieves distension.
Jinmengshi is a metamorphic rock—vermiculite schist or hydrobiotite schist. Traditional TCM holds that it subdues phlegm and descends qi, resolves accumulation and digests food, and pacifies the liver and settles fright. It is mainly used for stubborn bound phlegm, cough with rapid breath and wheezing, epilepsy and mania, irritability and chest oppression, convulsions and fright wind, hiccups, and dysphagia.
Overall, the prescribing logic of this formula is comprehensive, and it can indeed relieve the esophageal obstruction symptoms of esophageal cancer patients. But it is too corrosive and has relatively strong side effects, so it should not be used for long; once the patient can swallow, other drugs for esophageal cancer should be substituted.