Digitalis: historical development in clinical medicine

First total synthesis of rhodexin A

An efficient total synthesis of rhodexin A (1) is reported. An initial inverse-electron-demand Diels-Alder reaction of the acyldiene 6 with the silyl enol ether 7 gave the cycloadduct 8 with the required 4 contiguous stereocenters in a single step. This compound was then transformed into the tetracyclic enone 16, which was converted to rhodexin A (1).

Functional changes in isolated guinea-pig papillary muscle induced by monensin and digoxin

The effects of digoxin and monensin on contraction force (CF), initial contraction velocity (ICV), average contraction velocity (ACV), initial relaxation velocity (IRV) and stimulus to response time (ST) in 'fatigued' (tired) and 'non-fatigued' (fresh) guinea-pig papillary muscles were investigated. 'Fatigued' muscles had lost 30% of their original CF with the elapse of time before they were treated. The 5 h of measurement were divided into five periods (T0 was equilibration, T1, T2, T3 and T4 were, respectively, 1, 2, 3 and 4 h after drug administration). It was found that both monensin and digoxin increased the CF, ICV and ACV at T1 and increased the IRV at T2. Digoxin lost its effect with the elapse of time while monensin did not. Digoxin also decreased the ST at T2, T3 and T4. However, monensin did not change the ST. It was also found that 'fatigued' and 'non-fatigued' guinea-pig papillary muscles did not respond to the drug treatment differently. It was concluded that the initial effects of these two drugs on guinea-pig papillary muscles are similar regarding contractility but in time digoxin loses its effect while monensin does not.

Inappropriate use of digoxin in the elderly: how widespread is the problem and how can it be solved?

Cardiovascular disease is ubiquitous within the elderly population and requires treatment with multiple types of medications. As with any cardiovascular pharmaceutical regimen, the risk versus the benefit of each medication must be strongly considered. This is particularly true where, for various reasons, adverse effects are more often prevalent and pronounced. Over the years, it has been documented that digoxin is a frequently prescribed medication in elderly populations. Although this drug can be beneficial when used in the appropriate setting, recent data would suggest that inappropriate administration of digoxin is common and not without potentially serious consequences. Currently, the use of digoxin can be advocated to control heart failure in atrial fibrillation and when added to ACE inhibitors and diuretics in those patients with symptomatic heart failure related to systolic left ventricular dysfunction. It is likely that the excessive use of digoxin in elderly populations as discussed in this review is perhaps based on the prevalence of diastolic heart failure in the elderly as well as other co-morbid conditions that may mimic heart failure signs and symptoms. Since the elderly appear to be at high risk for digoxin toxicity, the inappropriate use of this medication to treat these conditions could result in significant and unnecessary morbidity. It is proposed that echocardiography should be performed in most elderly patients when congestive heart failure is suspected. This simple diagnostic tool, along with a careful history and medical examination, would hopefully prevent the misinterpretation of confusing clinical findings and would help to identify the patients with normal systolic function or valvular disease such as critical aortic stenosis, where digoxin treatment would not be warranted. If it is necessary to administer digoxin, then the likelihood of significant toxicity can be greatly reduced by using an algorithm to calculate the appropriate dosage, which takes into consideration the patient's gender, bodyweight and creatinine clearance. Although it is probable that the indications for digoxin use to treat congestive heart failure will continue to evolve, at the present time most would recommend using this agent in symptomatic heart failure related to a reduction in left ventricular systolic function or when associated with atrial fibrillation.