Precautions When Using Arsenic Compounds as Anticancer Agents

The great TCM classics of every era contain formulas using arsenic compounds to fight cancer, and clinically arsenic compounds do indeed have a reasonably good anticancer effect. Xionghuang (realgar, arsenic sulfide) and Pishuang (arsenic trioxide) are the most commonly used arsenicals, and both are highly toxic. Xionghuang is relatively safer; Pishuang is more toxic than Xionghuang. At present, Chinese authorities have classified Pishuang as a controlled substance, so ordinary physicians and patients essentially cannot obtain it, but Xionghuang is still widely used.

The Chinese patent medicines Liushen Wan, Niuhuang Xiaoxiao Wan, Meihua Dianshe Dan, Liuying Wan and others all contain Xionghuang; these are basically all formulas evolved from the ancient Shexiang Xionghuang San. Shexiang Xionghuang San is first recorded in Sun Simiao's Qianjin Fang of the Tang dynasty and was commonly used to treat carbuncles, sores, and toxin swellings; its main ingredients are Shexiang (musk), Xionghuang, and Chansu (toad venom). These formulas are all composed on the principles of using poison to attack poison and clearing heat and resolving toxin.

I myself also often use Liushen Wan and Meihua Dianshe Dan for anticancer purposes, especially for leukemia, lymphoma, and metastatic lymph node tumors. Patent medicines containing arsenic compounds can quickly lower the patient's white blood cell count and have a good effect on acute and chronic leukemia presenting with excessively high white cells. Liushen Wan and other arsenical patent medicines can also rapidly shrink lymphomas and metastatic lymph node tumors, but their side effects are greater than those of ordinary Chinese herbs or patent medicines, so they must be used with special care.

Xionghuang and other arsenicals should be used only briefly in patients whose disease is progressing rapidly, for Xionghuang rapidly lowers the white blood cells in the peripheral blood of leukemia patients. Researchers have found that taking 5–10g of Xionghuang powder daily (after levigation, placed in capsules), acute leukemia begins to show a falling white cell count within 2–10 days, and chronic myeloid leukemia within 3–7 days, averaging 6.2 days. Xionghuang is suitable for leukemia with elevated white cells; it is contraindicated in leukemia with reduced white cells. It should be used cautiously in cancer patients of any type whose white cell count is low after treatment.

Xionghuang's anticancer effect is obvious, but its myelosuppressive side effect is also obvious. Therefore, when taking Xionghuang-containing patent medicines, one must closely monitor the patient's white cell count and simultaneously pair the formula with TCM righteous-supporting formulas such as Shiquan Dabu Tang, Bazhen Tang, Huangqi Buxue Tang, or Guipi Tang, to prevent the white cells from dropping too low.

Arsenic compounds cause diarrhea in some patients and constipation in others. Thus, when taking arsenical anticancer drugs, one should pair them with appropriate herbs to mitigate side effects according to the patient's gastrointestinal response. Some folk remedies combine Xionghuang or Pishuang with Badou (croton); if one applies them blindly without understanding the medicine, this is extremely dangerous. Patients with weak spleen and stomach who take arsenicals alone can already develop severe diarrhea; adding Badou may produce diarrhea severe enough to cause shock, a serious medical accident. Badou may be combined only in patients who develop constipation after taking arsenicals, but even then Renshen, Huangqi, and Dazao must be used to support the righteous. Patients who develop diarrhea after arsenicals must be watched closely and given antidiarrheals when necessary.

When using arsenic compounds at low doses for anticancer purposes, the course should be stopped after 1–4 weeks. At high doses, after one week of use one must stop for 2–3 weeks, resuming only after the patient's righteous qi has recovered. Using poison to fight cancer must follow the ancient principle of "stop once the pathogen has been reduced by more than half"; once the patient's condition is controlled, switch to a formula with relatively milder side effects for gradual treatment.

Arsenic compounds have considerable toxic effects on multiple organs—the liver, kidneys, heart, and lungs. The physician should understand the patient's liver and kidney function and cardiopulmonary function before deciding whether to use arsenicals, and during use should instruct the patient to have periodic liver, kidney, and cardiopulmonary checks; one must not be reckless.

Once arsenicals are begun, the physician must closely watch changes in the patient's condition and general state. If the condition does not improve, arsenicals should be stopped as soon as possible. Even if the condition improves, the patient must be warned never to continue arsenicals long-term without interruption; periodic, scientifically grounded withdrawal is essential for safe use.

Family members should not try arsenic compounds on their own without a physician's guidance. Arsenicals usually require levigation (shuifei), chiefly to remove toxic impurities. But the levigation of Chinese herbs is technically tricky, and inexperienced laypeople should not use it indiscriminately.

Drugs containing arsenic compounds must also be stored away from high temperatures and direct sunlight. As the ancients said, "Xionghuang exposed to fire is as toxic as Pishuang"; under high heat or sun exposure part of the Xionghuang oxidizes into Pishuang, which is highly toxic. Improper storage or use of Xionghuang-containing drugs can therefore cause injury and death.