Digoxin-like immunoreactivity in Chinese medicine

Area of Science:

• Pharmacology and Toxicology
• Traditional Chinese Medicine
• Analytical Chemistry

Background:

• KYUSHIN, a popular Japanese herbal medicine, is derived from Chan-su.
• Chan-su contains cardiotonic steroids structurally similar to digoxin.
• Digoxin-like immunoreactivity has been detected in KYUSHIN.

Purpose of the Study:

• To quantify the digoxin-like immunoreactivity in KYUSHIN tablets.
• To assess the impact of typical KYUSHIN dosage on serum digoxin-like immunoreactivity.
• To highlight implications for therapeutic drug monitoring.

Main Methods:

• Immunoassays using commercial digoxin kits to measure immunoreactivity in KYUSHIN.
• Analysis of digoxin-like immunoreactivity in healthy volunteers after consuming KYUSHIN.
• Comparison of results across different immunoassay kits.

Main Results:

• One KYUSHIN tablet exhibited digoxin-like immunoreactivity equivalent to 1.5-72 micrograms of digoxin, varying by assay kit.
• This variation is likely due to differences in antibody cross-reactivity.
• A typical dose of KYUSHIN in healthy volunteers led to detectable serum digoxin-like immunoreactivity within 0.5 days.

Conclusions:

• KYUSHIN tablets possess significant digoxin-like immunoreactivity due to their cardiotonic steroid content.
• The presence of Chan-su in Chinese medicines can lead to false positives or altered levels in digoxin assays.
• Therapeutic drug monitoring for digoxin requires careful consideration in patients using Chinese herbal medicines like KYUSHIN.