Oral rehydration solution OS-1 plays an active role in clinical settings

Up until the early 1990s, our product development in the clinical nutrition area was centered on IV solutions, and although we were also working on enteral nutrition products as drugs, we had hardly focused on foods. However, we were surprised when we investigated trends in this area overseas. Clinical nutrition guidelines in Europe and the United States state that, when providing nutritional support to patients, if the gastrointestinal tract has the capacity for digestion and absorption, oral intake should be given priority. The approach is to first assess whether oral intake is possible. If not, then tube-based enteral nutrition would be selected. If that method is also not feasible, then nutrition is provided via IV. In other words, oral and enteral nutrition are given priority over IV solutions.

At that time in Japan, such guidelines were still insufficient, and physicians tended to choose intravenous nutrition as a matter of course when eating was difficult for the patient. This may also have been due to the lack of an established method for evaluating oral intake. However, looking at overseas trends, we were convinced that soon in Japan as well, clinical nutrition would be premised on oral intake. From IV drips to foods, could we provide a lineup of products that would lead to such a paradigm shift?

Around that time, a concept for a product was put forward by the top management to our research institute. The idea was to create a “Drinkable IV drip”, meaning a product that is easy to consume and enables replenishment of water and electrolytes. This became the catalyst for us to realize that there must be products within our lineup of infusion formulations that could be applied to oral nutrition, so we began to devote our efforts to research and development in the field of foods.

There are various types of IV drips. The simplest, for example, are water-and-electrolyte replenishment solutions used short term in cases of dehydration. Supplemental nutrition products are used if a patient cannot eat anything for about one to two weeks after surgery. If they are unable to eat for more than two weeks after surgery, then comprehensive nutrition products are used. However, for short-term use, it may be possible to avoid using an IV drip if a patient is able to drink.

Looking abroad, we found examples that seemed useful as references. We looked at the approach to oral rehydration therapy, which came to prominence during the global cholera outbreak in 1971. At that time, in developing countries where improvements in sanitation were lagging, infectious diseases, especially cholera, were widespread, and many people apparently lost their lives due to dehydration caused by diarrhea and vomiting. As a countermeasure, the approach to oral rehydration therapy was created to replenish water and electrolyte lost from the body and to help patients recover from or prevent dehydration. Because it was highly effective, pediatric societies in advanced countries took the lead in creating guidelines for managing dehydration in acute gastroenteritis using it, and when symptoms such as diarrhea and vomiting occurred due to infections, it was recommended to have patients drink oral rehydration solutions early. By doing so, patients might avoid becoming dehydrated, and even if they are hospitalized, the likelihood of preventing progression to a severity that necessitates an IV drip increases.

However, Japan did not have such guidelines. We began developing oral rehydration solutions, drawing on WHO’s approach to oral rehydration therapy and the American Academy of Pediatrics guidelines, and leveraging our expertise as a leading company in IV solutions. Its hallmark is a balanced formulation built on sodium and potassium, with trace amounts of magnesium and phosphorus tuned for intracellular fluid, plus carbohydrates to speed absorption from the intestines. However, that alone did not make it satisfactory as a product. We needed to make it easier to drink. Another challenge was extending the shelf life and ensuring stability so the taste would not change over time. In the end, we think we tested over 1,000 combinations before the product was launched. After overcoming those two challenges, which were drinkability and stability, we introduced Oral Rehydration Solution OS-1 in 2001.

OS-1 is a product designed for patients in a dehydrated state, primarily to meet medical needs in the clinical nutrition area. However, since it has the appearance of a “refreshment beverage”, we were uncertain about how well the market would accept it. Therefore, we initially limited sales to the Kanto and Shikoku areas.

A particular topic of debate internally was that the Otsuka Group already had a well-known beverage brand characterized by water and electrolytes being readily absorbed by the body. While a comparison of their sodium and potassium compositions makes the differences obvious, we were concerned that average consumers might not see the distinction and the products would compete in the market. Therefore, we concluded that we needed to create a completely different product category.

As noted, OS-1 was originally developed to meet the medical need for the approach to oral rehydration therapy. However, it is a food, not a drug. We were concerned with how a product in that position could clearly be distinguished from the rest. What gave us a hint to a solution was “food for persons with medical conditions,” a category of products which is now overseen and approved by the Consumer Affairs Agency. We believed that creating a new category, foods for oral rehydration therapy, would be the key to differentiating OS-1 from other products. To obtain labeling approval as a food for persons with medical conditions, it is necessary to demonstrate in clinical studies that the medical and nutritional effects are clear. We steadily built up a track record of use in medical institutions, submitted data and papers from clinical studies, and in 2004 obtained approval to label it as a food for persons with medical conditions. At that time, we also began nationwide sales of the product in Japan.

A food for persons with medical conditions is required to display that it should be used under the guidance of physicians, pharmacists, nurses, and registered dietitians. Once we moved to nationwide sales in Japan, our first step was to communicate the significance of the approach to oral rehydration therapy to healthcare professionals and to make OS-1 known to them. In particular, we emphasized to pediatricians that the product aligns with overseas guidelines for the approach to oral rehydration therapy. We also needed to expand sales channels so that OS-1 could be purchased when directed by a physician. Initially, sales were limited to hospital shops and dispensing pharmacies, but as product recognition grew, we received more inquiries and requests from customers, such as “Tell me where OS-1 is sold” and “Please make it available at drugstores.” Therefore, we consulted the relevant authorities and expanded distribution to drugstores with pharmacists. Then, in the 2010s, as heatstroke began to be frequently covered by the media and general awareness of dehydration countermeasures finally grew, we started running TV commercials to raise understanding of the effectiveness of the approach to oral rehydration therapy and of OS-1.

As OS-1 came to be accepted as an option for dehydration countermeasures, new developments also emerged among healthcare professionals. It is now being used in a variety of settings, leveraging the defining feature of an oral rehydration solution, which is the rapid replenishment of water and electrolytes the body lacks.

In medical institutions and long-term care facilities, dehydration countermeasures for older adults are a key issue. It is thought that many older adults living alone and in households where elder-to-elder care is provided people are chronically prone to dehydration. There must be many potential candidates for the approach to oral rehydration therapy. However, we must be careful with older adults, as those who are unable to swallow are at risk of aspiration pneumonia and other issues. OS-1 Jelly is a version of the product with modified physical properties designed with these older adults in mind.

During disasters, people are prone to poor health in the special environments of shelters and temporary housing. Infection risks rise in such environments, causing concern about dehydration resulting from diarrhea and vomiting. Therefore, stockpiled items compatible with the approach to oral rehydration therapy are needed. OS-1 also offers powder products suitable for long-term storage, so we can meet these needs as well.

Fifteen years have passed since the launch of OS-1, the market for oral rehydration solutions has grown, and the field of medical foods is becoming one of the pillars of our business. We have also established a specialized organization called the Medical Foods Research Institute, and we are currently developing successors to OS-1 and bringing them to market. We are also looking ahead to overseas expansion. There is still much we need to do to realize the paradigm shift we aim for.

(Affiliated departments and job titles current as of the time of the interview.)