On the Clinical Use of Digitalis on the Clinical Use of Digitalis with Reference to Its Prescription, Maintenance Therapy, Intoxication and the Patient's Knowledge

On the Clinical Use of Digitalis with reference to its prescription, maintenance therapy, intoxication and the patient's knowledge. Kurt Boman, M.D., Departments of Internal and Geriatric Medicine Skellefteå Hospital and Institution of Internal Medicine, University of Umeå, S-901 87 Umeå, Sweden. Digitalis is one of the most frequently prescribed drugs, especially to elderly people. The prescription of cardiac glucosides (1978) was studied by using statistics from Apoteksbolaget (the National Corpora­ tion of Swedish Pharmacies). There was a threefold difference in the sales of cardiac glucosides per 1000 inhabitants in the different primary care areas. Digoxin was prescribed to 90-98 per cent of the patients, with considerable variations in the dosages. Many other factors besides the cardio-vascular morbidity were likely to cause these differences. Maintenance digitalis therapy has lately been questioned. In a retro­ spective study, digitalis was discontinued in 141 geriatric patients without contraindications to digitalis withdrawal. Digoxin treatment seemed to be unnecessary in 108 patients (81 per cent), followed up two months after digoxin withdrawal. A long-term study (mean: 20,5 months) was carried out in these 108 patients. Digitalis therapy was reinstituted in 30 of 99 patients, equally distributed on the basis of clear, possible or uncertain indications. Significantly more patients (p<0,001) with atrial fibrillation compared with sinus rhythm were restarted. A prospective, randomized, double-blind placebocontrolled study in 39 out of 66 geriatric patients confirmed the results of the retrospective study. During a two-month period 32 of 37 patients (86 per cent) managed without digitalis. Eighteen out of 66 patients (27 per cent) presented contraindications to digoxin with­ drawal. Those who needed digitalis were restarted mainly during the first month (mean: 18 days) following digoxin withdrawal. Digitalis intoxication has been studied earlier, mainly in hospitalized patients. A clinical examination and BOG of a random sanple of out­ patients treated with digoxin showed that about 5 per cent were certainly intoxicated and about 2 per cent suspected of being intoxi­ cated. Elderly patients are said to be more sensitive to digitalis. Eleven per cent of 66 geriatric patients were found, without doubt, to be digitalis intoxicated. The mean serum digoxin concentration was significantly higher in eight toxic patients compared with non-toxic patients, but 75 per cent of the toxic patients had serum digoxin con­ centrations within or below therapeutic range. Five of these intoxi­ cated patients did not need maintenance digitalis therapy. A questionnaire of 361 patients in Skellefteå and Uppsala revealed that about 45 per cent had taken digitalis for more than five years. Approximately 85 per cent took one tablet daily and stated compliance. About one fifth did not know why they were taking digoxin and about half of the patients were uncertain if they were improved by digitalis therapy. Although digitalis intoxication is such an important clinical problem, some 55 per cent did not knew about digitalis's side-effects and some 50 per cent stated that no or insufficient information had been given. Only 15 per cent were satisfied with the information they had received. A significant negative correlation between digoxin dosages and the age of the patients was found.