These drugs, a subset of monoamine oxidase inhibitors (MAOIs), inhibit only isoenzyme A and are reversible. Isoenzyme B remains free to metabolize tyramine contained in some foods, so they are safer and may not require a special diet.
Because their action is short-lived and selective, they have a better safety profile than the older MAOI drugs (monoamine oxidase inhibitors). A special diet does not need to be so strictly adhered to, although eating excessively large amounts of tyramine-containing foods is not advisable.
Combining a RIMA or MAOI with an SSRI is dangerous since it can lead to serotonin syndrome and possible fatality.