A medicine that costs only a few cents a day could become more important in treating one of the world’s most difficult heart conditions.
New research from the University Medical Center Groningen suggests that carefully using low-dose digoxin may help people with heart failure stay out of hospital.
Digoxin is far from a new drug. Versions of digitalis medicines have been used for centuries, but the drug gradually lost its central place in heart failure treatment as newer and more effective medicines became available.
Now three studies led by UMCG cardiologists Dirk Jan van Veldhuisen, Kevin Damman, and Peter van der Meer have renewed interest in it. Results were reported in publications including Nature Medicine and JAMA and presented at the ESC Heart Failure Congress in Barcelona.
Heart failure develops when the heart cannot pump blood efficiently enough for the body’s needs. It can follow a heart attack, years of high blood pressure, heart muscle disease, damaged heart valves, or other conditions that weaken or strain the heart.
The condition can make ordinary activities exhausting. People may become breathless while walking, feel weak, develop swollen ankles, or wake at night struggling to breathe because fluid has collected in the lungs.
Hospitalization is a major concern because symptoms can suddenly worsen. Preventing these episodes is one of the central goals of modern heart failure treatment.
Doctors now have several medicines that can help people live longer and reduce hospital admissions. Four major drug groups form the foundation of treatment for many patients and are sometimes nicknamed the “Fantastic Four.”
Despite these advances, heart failure remains a serious problem. In the Netherlands alone, more than half a million people are estimated to have it, and the number is expected to increase as the population ages.
The UMCG researchers wanted to know whether a very low dose of digoxin could add another layer of protection. Importantly, they were not trying to return to the higher doses commonly used in earlier decades.
The main trial recruited around 1,000 patients from 43 centers in the Netherlands. Everyone continued receiving their normal heart failure care, but half were given low-dose digoxin while the other half received a placebo.
Participants were followed for about three years on average. The researchers found 19% fewer cardiovascular deaths and episodes of worsening heart failure in the digoxin group, but this result alone was not statistically significant.
In simple terms, the study could not confidently rule out the possibility that this particular difference happened by chance. That did not end the investigation, because researchers also had evidence from previous trials.
They combined the new results with two earlier studies in a meta-analysis. Pooling the information created a larger evidence base and made it easier to detect whether a real treatment effect was present.
The strongest result was seen in heart failure hospitalizations. Across the combined evidence, low-dose digoxin reduced hospital admissions for worsening heart failure by about 25%.
A reduction of that size could matter greatly in everyday care. Avoiding hospitalization can mean fewer frightening episodes for patients, less disruption for families, and lower costs for health services.
Why might an old drug still help when modern medicines are already being used? The answer may lie partly in the difference between low and high doses.
Digoxin can increase the strength of heart contractions, which was once considered one of its main advantages. But pushing a weakened heart to work harder is not necessarily the best long-term strategy.
At lower doses, digoxin may have a different balance of effects. It can help reduce some of the body’s excessive stress responses that develop when the heart is struggling, including signals involving hormones such as adrenaline.
These stress systems are useful during short emergencies, but constant activation can become harmful. Reducing that strain may help the heart work under less pressure rather than simply forcing it to beat more strongly.
The researchers also examined what happened when some trial participants stopped taking digoxin. About 600 people were included in this follow-up analysis.
During the first six weeks after stopping treatment, people who had previously received digoxin experienced noticeably more problems than those who had been receiving placebo. Among 288 former digoxin users in the analysis, 14 were hospitalized or died.
This finding was unexpected and does not independently prove that stopping digoxin caused the events. However, it adds another piece of evidence suggesting that the drug may have been providing useful protection while patients were taking it.
Safety is especially important with digoxin because too much of the drug can be toxic. High levels can cause nausea, confusion, abnormal heart rhythms, and other serious problems, and the medicine needs particular care in people with reduced kidney function.
The new research focused on low-dose treatment, which the investigators found was generally safe and manageable. This lower-dose approach is central to why today’s results differ from some older experiences with the drug.
Cost is another unusual feature of the story. Digoxin costs less than ten cents per day, making it dramatically cheaper than many recently developed medicines.
That could make it particularly useful if its benefits are confirmed across suitable groups of patients. Affordable treatments can be important not only in wealthy healthcare systems but also in places where expensive heart failure drugs are difficult to obtain.
The studies also highlight a problem in medical research. Because digoxin is old and inexpensive, there is little commercial reward for a pharmaceutical company to spend millions testing new uses for it.
The Dutch Heart Foundation helped overcome that barrier by providing 3 million euros through work with ZonMw’s Good Use of Medicines program. Public and nonprofit funding can be especially important when researchers want to test whether cheap existing drugs still have untapped value.
When the findings are weighed together, the reduction in hospital admissions is the strongest reason for renewed interest in digoxin. The main randomized trial provides valuable evidence, and the combined analysis strengthens the case that low doses may offer additional benefits even alongside modern treatment.
There are still reasons for caution. The main trial’s 19% improvement in its cardiovascular outcome did not reach statistical significance by itself, and digoxin has a narrow safety range that makes appropriate dosing and medical monitoring important.
The results should therefore not be interpreted as a reason for patients to start digoxin on their own or to change an existing dose. Whether it is appropriate depends on the type of heart failure, kidney function, heart rhythm, other medicines, and the patient’s overall condition.
If future studies and guideline reviews support these results, digoxin could move from being viewed mainly as an old-fashioned heart medicine to becoming a useful fifth option for selected patients. Its combination of possible benefit, low cost, and long clinical experience makes it an unusually interesting candidate for a comeback.
Source: University Medical Center Groningen.
