Could a Common Diarrhea Pill Treat Autism?

A commonly used anti-diarrhea drug available in chemists worldwide could offer new hope for a treatment for autism spectrum disorders (ASD).

Researchers believe that the anti-diarrheal drug loperamide has the potential to treat the core social symptoms of ASD.

The surprising finding came from computer analysis of existing drugs to see which ones might affect proteins involved in ASD.

“There are no medications currently approved to treat social communication deficits, the main symptom of ASD,” said Dr. Elise Koch, from the University of Oslo and the study’s lead author.

“However, most adults and about half of children and adolescents with ASD are treated with antipsychotic drugs that have serious side effects or are ineffective in ASD.”

The researchers said the reason a drug apparently unrelated to ASD could offer treatment is because of how it works in the body.

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Loperamide binds to and activates a protein called the μ-opioid receptor, which is normally affected by opioid drugs such as morphine.

The receptor also affects social behavior, and in previous research, genetically engineered mice lacking the μ-opioid receptor exhibited social deficits similar to those seen in ASD.

Drugs that activate the μ-opioid receptor helped restore social behavior, the researchers said.

These findings in mice highlight the tantalizing possibility that loperamide or other drugs targeting the μ-opioid receptor may represent a new way to treat the social symptoms present in ASD.

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The researchers cautioned that further work was needed to test this hypothesis.

They turned to drug repurposing, which involves exploring existing drugs as potential treatments for a different condition.

The approach has many advantages, as there is often extensive knowledge of existing drugs in terms of their safety, side effects and the biological molecules they interact with in the body.

The researchers used a computer-based protein interaction network. Such networks look at proteins and the complex interactions between them.

The researchers constructed a protein interaction network that included proteins associated with ASD.

By examining existing drugs and their interaction with proteins in the network, the team identified several candidates that counteract the biological process underlying ASD—the most promising of which was loperamide.

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