Phenelzine is a member of a group of drugs called monoamine oxidase (MAO) inhibitors (also
called MAOIs). Phenelzine is sometimes used to treat people with depression who do not respond to other antidepressant
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
| May Be Beneficial: Depletion or
interference—The medication may deplete or interfere with the absorption or
function of the nutrient. Taking these nutrients may help replenish them.
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results.
Ginseng (species not specified)*
St. John’s wort*
|Side effect reduction/prevention
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
Interactions with Dietary Supplements
Phenelzine has a chemical structure similar to other drugs (isoniazid and hydralazine) that can cause vitamin B6 deficiency. One
case of phenelzine-induced vitamin B6 deficiency has been reported.1 Little is
known about this interaction. People taking phenelzine should ask their doctor about
monitoring vitamin B6 levels and considering supplementation.
Interactions with Herbs
Ephedra contains the chemical ephedrine, which
may interact with phenelzine, causing potentially dangerous changes to blood
pressure.2 People should read product labels for ephedra/ephedrine content. Ephedra
and ephedrine-containing products should be avoided during phenelzine therapy. People with
questions about phenelzine and ephedra/ephedrine should ask their doctor or pharmacist.
Ginseng (species not specified)
In a case report of a woman treated with phenelzine, addition of a ginseng-containing tea was
associated with insomnia, headache, and
tremor.3 Other contents of the tea were not reported. In a case report of a woman
treated with phenelzine for depression,
addition of ginseng (not further identified) was associated with hypomania (a mild form of
mania), which the patient had not previously experienced.4 Until more is known,
people should combine ginseng and phenelzine with caution after consulting a knowledgeable
Although St. John’s wort contains chemicals that bind MAO in test tubes, it is believed
that the action of St. John’s wort is not due to MAOI activity.5 However,
because St. John’s wort may have serotonin reuptake inhibiting action (similar to the
action of drugs such as Prozac®, it is best to avoid concomitant use of St. John’s
wort with MAOI drugs.
Scotch broom (Cytisus scoparius)
Scotch broom contains high levels of tyramine. Combining phenelzine and Scotch broom may cause
MAOI-type reactions (diarrhea, flushing,
sweating, pounding chest, dangerous changes in blood pressure, and other
symptoms).6 It is important for people taking phenelzine to avoid Scotch broom.
People with questions about phenelzine and Scotch broom should ask their doctor.
Interactions with Foods and Other Compounds
Phenelzine can alter metabolism of a chemical called tyramine that is present in certain
foods, leading to diarrhea, flushing,
sweating, pounding chest, dangerous changes in blood pressure, and other symptoms.7
It is important for people taking phenelzine to avoid tyramine-containing foods. People with
questions about phenelzine and tyramine-containing foods should ask their doctor or
Two cases were reported involving men treated with phenelzine who experienced restlessness,
agitation, tremor, and insomnia after drinking large quantities of cola beverages containing
aspartame.8 Until more is known, people taking phenelzine should use
aspartame-containing foods with caution.
1. Heller CA, Friedman PA. Pyridoxine deficiency and peripheral
neuropathy associated with long-term phenelzine therapy. Am J Med
2. Threlkeld DS, ed. Central nervous system drugs, antidepressants,
monoamine oxidase inhibitors. In Facts and Comparisons Drug Information. St. Louis,
MO: Facts and Comparisons, Apr 1997, 264y.
3. Shader RI, Greenblatt DJ. Phenelzine and the dream machine-ramblings
and reflections. J Clin Psychopharmacol 1985;5:65.
4. Jones BD, Runikis AM. Interaction of ginseng with phenelzine. J
Clin Psychopharmacol 1987;7:201–2.
5. St. John’s wort, Hypericum perforatum. In American
Herbal Pharmacopoeia and Therapeutic Compendium, ed. R Upton. Santa Cruz, CA: AHP,
6. Brinker F. Interactions of pharmaceutical and botanical medicines.
J Naturopathic Med 1997;7(2):14–20.
7. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants,
Monoamine Oxidase Inhibitors. In Facts and Comparisons Drug Information. St. Louis,
MO: Facts and Comparisons, Apr 1997, 264y.
8. Shader RI, Greenblatt DJ. Phenelzine and the dream machine-ramblings
and reflections. J Clin Psychopharmacol 1985:5:65.