Chan Pi

A phase 1 dose-escalation study of huachansu (cinobufacini), the sterilised hot-water extract of dried Bufo gargarizans skin, which is the injectable form of this very drug. Fifteen patients (11 hepatocellular, 2 non-small-cell lung, 2 pancreatic) received intravenous huachansu for 14 days of each 21-day cycle at 10 to 90 mL/m2. No dose-limiting toxicity was found even at eight times the dose used routinely in China, 11 patients had no drug-related toxicity above grade 1, and six had prolonged stable disease or minor tumour shrinkage. It is a single-arm dose-finding study of an intravenous extract, not evidence that oral toad skin is safe or effective, and it says nothing about the cardiac risk of ingesting the crude drug.

Seventeen trials of huachansu, described as the sterilised water extract of Bufo bufo gargarizans toad skin, added to chemotherapy in advanced non-small-cell lung cancer. Pooled results favoured the huachansu arms for objective tumour response, one-year survival, Karnofsky performance status, pain relief, nausea and vomiting and leukocytopenia, with no difference in thrombocytopenia. All included trials were Chinese and the authors themselves note the need for higher-quality trials; the pooled effect should be read with the well-documented positive-result bias of this literature in mind.

An aqueous extract of Chan Su added to drug-free serum produced an apparent digoxin concentration of 2.76 ng/mL by fluorescence polarization immunoassay and 0.94 ng/mL by microparticle enzyme immunoassay, with no signal on a monoclonal chemiluminescent assay. In serum containing digoxin the interference was positive with FPIA and negative with MEIA, so the same sample could be reported as toxic on one analyser and subtherapeutic on another. Because the bufadienolides are highly protein-bound while digoxin is only about 25% bound, measuring free digoxin eliminated the interference in both directions.

Five previously healthy men fell ill after ingesting a substance marketed as a topical aphrodisiac and four died of cardiac dysrhythmias. All five had measurable serum digoxin although none had been prescribed it and none had a condition producing endogenous digoxin-like immunoreactive substances. Analysis showed the product contained bufadienolides and was identical to Chan Su. This is the case series that established both the lethality of ingested toad preparations and the immunoassay trap that made the diagnosis.

A California Department of Health Services investigation of a fatal poisoning after ingestion of a Chinese herbal tea containing ch'an su, with laboratory characterisation of the product. It documents that the hazard reaches patients through ordinary herbal channels and not only through aphrodisiac products.

Clinical report of toad venom poisoning treated with digoxin-specific antibody Fab fragments, the paper that put Fab on the map as the antidote for bufadienolide poisoning in humans. It is the practical counterpart to the immunoassay problem: the same antibody cross-reactivity that ruins the assay is what makes the antidote work.

A controlled mouse model of Chan Su poisoning showing that digoxin-specific Fab fragments improve survival, supporting their use for poisoning by bufadienolide-class cardioactive steroids generally and not only for digoxin.

Gas chromatography-mass spectrometry showed the aphrodisiac product Love Stone and the Chinese medication Chan Su to be the same material, both containing bufotenine and related bufadienolides. This is the analytical link between a street product and a pharmacopoeial animal drug, and the reason bufotenine's controlled-substance status attaches to toad preparations.

A case report comparing the conduction abnormalities produced by bufadienolide overdose from a Chinese aphrodisiac with those of digoxin overdose, finding them electrophysiologically alike. It supports managing bufadienolide poisoning along digitalis lines, including the use of digoxin-specific Fab.

Review and experimental account of the antitumour activity of toad skin extracts and their isolated bufadienolides, the preclinical basis for cinobufacini/huachansu. It is skin-derived material, matching the drug described by this record, rather than the venom secretion.

Isolation and structural characterisation of a structurally varied set of bufadienolides from the skins of Bufo gargarizans, with cytotoxicity testing. It confirms that the skin drug, not only the venom, carries a complex mixture of cardiotonic steroids, so Chan Pi cannot be treated as a milder or glycoside-free version of Chan Su.