Serum Digoxin Assays: Investigation of Use and Abuse

Abstract

Digoxin requesting patterns were studied prospectively over a 6-month period. Clinicians were not forewarned that the study was being undertaken. Many samples received in the laboratory were taken at incorrect times after the drug had been given. This led to inappropriate action being taken in some cases. Appropriate action was taken on most patients who had toxic serum digoxin levels together with clinical signs. The role of subtherapeutic digoxin levels seems unclear as these elicit a wide variety of responses.

Inappropriate digoxin monitoring

“…Therapeutic drug monitoring services for digoxin are often misused through inappropriate requests for assays, incorrect sample timing and poor interpretation of the results (1)(2)(3)(4)(5). Digoxin is potentially a good candidate for therapeutic drug monitoring because the drug has a narrow therapeutic index, and the plasma concentration and therapeutic response are related.…”