What study data is available on the effect of DMC?

Dextromethorphan/quinidine (DMC) was originally developed for the treatment of unwanted laughing and crying (motor disinhibition) and was approved in the USA in 2010 under the name “Nuedexta”. However, the use of DMC revealed another property – the improvement of speech and swallowing (“bulbar symptoms”). This effect on bulbar symptoms exists independently of the original application, so that DMC is used to reduce the speech and swallowing disorder in some patients, while other patients receive the medication to control the symptoms of unwanted laughter and crying.

The positive effect on bulbar symptoms was confirmed and published in two clinical studies in the USA (2017 and 2023). The mean improvement was 12 % in speech function and over 50 % in swallowing – with treatment with DMC for 28 days. The “statistical” effect of the drug is moderate, but DMC may or may not have a greater individual effect. Study data for symptomatic medications generally do not allow any “guarantee” for the response in individual patients, so that the individual effect can only be assessed after a treatment trial.