solution in chloroform. the solution was then reacted with acetic acid and small amount of ferric chloride and sulfuric acid (keller reaction). digoxin was distinguishable from other glucosides by the olive-green colored solution produced from this reaction, completely free of red. society and culture charles cullen admitted in 2003 to killing as many as 40 hospital patients with overdoses of heart medication—usually digoxin—at hospitals in new jersey and pennsylvania over his 19-year career as a nurse. on march 10, 2006, he was sentenced to 18 consecutive life sentences and is not eligible for parole. on april 25, 2008, the u.s. federal drug administration (fda) issued a press release alerting the public to a class i recall of digitek, a brand of digoxin produced by mylan. some tablets had been released at double thickness and therefore double strength, causing some patients to experience digoxin toxicity. a class-action lawsuit against the icelandic generic drug maker actavis was announced two weeks later. on march 31, 2009, the fda announced another generic digoxin pill recall by posting this company press release on the agency's web site: "caraco pharmaceutical laboratories, ltd. announces a nationwide voluntary recall of all lots of digoxin tablets due to size variability". a march 31 press release from caraco, a generic pharmaceutical company, stated: tablets of caraco brand digoxin, usp, 0.125 mg, and digoxin, usp, 0.25 mg, distributed prior to march 31, 2009, which are not expired and are within the expiration date of september, 2011, are being voluntarily recalled to the consumer level. the tablets are being recalled because they may differ in size and therefore could have more or less of the active ingredient, digoxin. a 2008 study suggested digoxin has beneficial effects not only for the heart, but also in reducing the risk of certain kinds of cancer. however, comments on this study suggested that digoxin is not effective at reducing cancer risk at therapeutic concentrations of the drug, so the results need further investigation. brand names digoxin preparations are marketed under the brand names cardigox; cardiogoxin; cardioxin; cardoxin; coragoxine; digacin; digicor; digomal; digon; digosin; digoxine navtivelle; digoxina-sandoz; digoxin-sandoz; digoxin-zori; dilanacin; eudigox; fargoxin; grexin; lanacordin; lanacrist; lanicor; lanikor; lanorale; lanoxicaps; lanoxin; lanoxin pg; lenoxicaps; lenoxin; lifusin; mapluxin; natigoxin; novodigal; purgoxin; sigmaxin; sigmaxin-pg; toloxin. digoxin and cancer cardiac glycosides, particularly digoxin, have been conventionally used for treatment of common cardiac problems, mainly heart failure and cardiac arrhythmias. the interaction of digoxin and cancer has also been studied. despite existence of numerous preclinical studies that investigated the anticancer effects of digoxin, there are no solid and conclusive results so far. several studies have suggested that digoxin may have anticancer properties, others not. digoxin, as a cardiac glycoside, has a chemical structure basically similar to that of estradiol. digoxin has the ability to bind oestrogen receptors, and therefore it has been proposed that it might increase the risk of oestrogen-sensitive breast and uterine cancers. a large danish study found a complicated picture, with slightly increased risk of breast cancer amongst women taking digoxin, but better prognostic features. the nurses' health study found a similar slight increase of risk. digoxin inhibits the proliferation of many cancerous cell lines in vitro, but its relevance to cancer in vivo remains unclear.