Ouabain, also called g-strophanthin, is a treatment for heart failure and problems with the atrium. Though it is not widely used, doctors that prescribe this treatment indicate that it is particularly effective, increasing heart function without endangering the heart through rapid heart rate or high blood pressure. Its use in human patients is limited to France and Germany, though the medication is used in studies in other parts of the world. Historically, ouabain has been used as a poison.
Ouabain is found in vines endemic to regions in Africa and Asia. People inhabiting regions where ouabain can be found frequently use the substance as a poison that, when applied to arrow heads or the tips of spears, causes cardiac arrest in animals. The poison can enter the bloodstream through small cuts, so even an arrow that merely grazes an animal can deposit enough poison to cause death.
The chemical in ouabain works by increasing the amount of sodium that is drawn into the cellular membrane. This increase results in an increase in calcium in the cells which make the heart beat more strongly. While large doses of this chemical can result in death, small doses can increase cardiac function without putting a patient at any risk. The chemical can be used to treat cardiac disorders, including heart failure and fibrillation, or flutter, of the atrium.
Treatment with ouabain was first embraced by Western medicine in the middle of the 20th century. Dr. Berthold Kern, a German physician was reviewing the properties of the seeds of plants in the Apocynaceae family and determined that low doses of them could lower cellular pH, which would restore heart function without increasing the strength of heart contractions. Though treatment with ouabain is not mainstream, there are many doctors in Germany and France that continue to prescribe it. These doctors generally give a positive report of the effects of the drug. Though the costs of this medication are relatively low, the lack of clinical trials in the United States has kept the medication unavailable in this country.
There are few reported side effects from treatment with ouabain. It is generally better tolerated than similar drugs, has fewer gastrointestinal effects, and significantly decreases blood pressure and heart rate. This medication also has a reputation for having a positive effect on patients with decreased lung function, such as those recovering from pneumonia.