= Solution
\b[The sound historical indication was selected dropsical states associated with disordered cardiac action; the modern uses of particular <cardiac glycosides> are narrower and explicitly rhythm-dependent.] A <digitalis preparation> was not simply a drug for every slow urinary flow or rapid <pulse>.
Before 1866, <William Withering>'s account had already demonstrated both the possible relief of dropsy and the danger of careless use. He recorded successes and failures and warned about <nausea>, <vomiting>, visual disturbance and excessive slowing of the <pulse>. These observations support careful assessment of effect and toxicity, not a method of administering foxglove until poisoning occurs.<An Account of the Foxglove and some of its Medical Uses by William Withering>[1785, Preface; Effects, Rules, and Cautions]{ref} The historical assessment would follow breathing, swelling, <pulse>, <urine> and general condition. Increased <urine> and reduced <oedema> could represent relief while the original cardiac disorder persisted.
Calling the drug a cardiac “sedative” from the slowing of the <pulse> could obscure a different effect on contraction. Likewise, apparent diuresis did not establish it as a universal remedy for renal dropsy. Period applications extended into febrile or haemorrhagic illnesses, but such claims should not be promoted into modern indications merely because the <pulse> changed. The problem is to distinguish treatment of a useful physiological target from suppression of a sign.
\b[Modern correction: <digoxin> increases myocardial contractility and slows conduction through the <atrioventricular node>.] In selected <heart failure> it can improve symptoms and reduce hospitalization. A randomized, placebo-controlled trial in people with chronic <heart failure> and normal <sinus rhythm> found fewer hospitalizations but no reduction in overall mortality.<The Effect of Digoxin on Mortality and Morbidity in Patients with Heart Failure by the Digitalis Investigation Group>[1997, main trial, Methods, Results and Conclusions]{ref} It can also control resting ventricular rate in selected adults with chronic <atrial fibrillation>. It is not a general treatment for a fast <pulse>, and the presence of an accessory conduction pathway can make its use hazardous. <Ventricular fibrillation> is a contraindication.<Digoxin prescribing information on DailyMed>[Indications 1.1 and 1.3; Contraindications; warning 5.1; mechanism of action 12.1]{ref}
The margin between useful and toxic exposure is small. Renal function, age, body composition, interactions and <electrolyte> disturbances influence risk. Monitor the clinical response, <electrocardiogram>, relevant laboratory results and drug concentrations when indicated. <Nausea>, <vomiting>, visual symptoms, marked <bradycardia> or new <cardiac arrhythmias> should raise concern for toxicity, not be treated as confirmation that the drug is beginning to work.<Digoxin prescribing information on DailyMed>[Sections 2.1 and 2.5; 5.2–5.3; 8.6, renal impairment]{ref} Historical leaf or tincture preparations must therefore not be substituted for a modern standardized preparation, or converted into modern doses from a shared name alone.
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