Phenelzine

Also indexed as: Nardil®

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 drug therapy.

Summary of Interactions with Vitamins, Herbs, and Foods
(for details about the summarized interactions, read the full article)

Beneficial 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.

Vitamin B6
Avoid Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.

Aspartame*

Ephedra*

Ginseng (species not specified)*

Scotch broom

St. John’s wort*

Tyramine-containing foods
Side effect reduction/prevention

None known
Supportive interaction

None known
Reduced drug absorption/bioavailability

None known

An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions with Dietary Supplements

Vitamin B6
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 sinica (Ma huang)
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 doctor.

St. John’s wort (Hypericum perforatum)
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

Tyramine-containing foods
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 pharmacist.

Aspartame
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.

References

1. Heller CA, Friedman PA. Pyridoxine deficiency and peripheral neuropathy associated with long-term phenelzine therapy. Am J Med 1983;75:887–8.

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, 1997.

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.