Cases of
serotonin syndrome, have been seen when
dextromethorphan has been used with non-selective
MAOIs. The likelihood of an interaction with
MAO-B inhibitors would appear to be very small, but because of the potential severity, some caution would appear to be prudent.
The manufacturer of
rasagiline contraindicates its use with
dextromethorphan. Some consider that patients taking selegiline should also try to avoid dextro- methorphan.