Duloxetine and Phenelzine interaction
Duloxetine and Phenelzine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Duloxetine label · effective 2026-03-02
Duloxetine Delayed-Release Capsules are contraindicated in patients who are using or within 14 days of stopping an MAOI intended to treat psychiatric disorders because of an increased risk of serotonin syndrome.
Allow at least 5 days after stopping Duloxetine Delayed-Release Capsules prior to initiation of an MAOI to treat psychiatric disorders. [see Dosage and Administration ( 2.7 ), Warnings and Precautions ( 5.4 )]. who are using other MAOIs such as linezolid or intravenous methylene blue because of an increased risk of serotonin syndrome [see Dosage and Administration…
Concomitant use of monoamine oxidase inhibitors (MAOIs), or use within 14 days of stopping MAOIs ( 4 )
Serotonin Syndrome: Increased risk when co-administered with other serotonergic agents but also when taken alone.
The concomitant use of Duloxetine Delayed-Release Capsules with MAOIs is contraindicated.
From the Phenelzine (phenelzine sulfate) label · effective 2026-05-21
Anyone considering the use of phenelzine sulfate or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need.
At least 14 days should elapse between the discontinuation of phenelzine sulfate and the institution of another antidepressant or buspirone HCl, or the discontinuation of another MAO inhibitor and the institution of phenelzine sulfate.
Concomitant Use with Dibenzazepine Derivative Drugs If the decision is made to administer phenelzine sulfate concurrently with other antidepressant drugs, or within less than 10 days after discontinuation of antidepressant therapy, the patient should be cautioned by the physician regarding the possibility of adverse drug interaction.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.