In 2020, a French team studied self-reports of memantine abuse posted on discussion forums.  Memantine is a drug authorised for use in Alzheimer's disease.

Between 2010 and 2019, 307 discussions citing memantine were identified on the “reddit” social network. 136 self-reports of memantine user experiences were studied, of which 39 related to recreational use.

The average dose taken for these recreational purposes was 156 mg, i.e. 8 times the maximum therapeutic daily dose.

The experience being sought was a dissociative state, i.e. a disorder of perception, including hallucinations, time/space distortion, altered perception of the environment and of one’s own body.  The self-reports described dissociation as developing slowly over several hours and lasting an average of 47 hours, which is consistent with the long half-life of memantine (around 60 hours).

One hundred self-reports also described regular use for self-medication, unrelated to Alzheimer disease. The average dose was 23 mg per day for 15 weeks. The effects being sought were mainly relief of anxiety, depression, attention deficit hyperactivity disorder, or obsessive compulsive disorder. In some cases, they were looking for enhanced cognitive function. 77% of these long-term users reported adverse effects including dissociation, clouding of consciousness, anxiety and insomnia.

©Prescrire 1 June 2021

Source: "Memantine: dissociative disorders" Prescrire International 2021; 30 (227): 159. Subscribers only.

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