Drug
Phenelzine
Pronounced
"FEN-el-zeen"
Drug Interactions
See also How to Use section.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: other antidepressants (including maprotiline, mirtazapine, nefazodone, TCAs such as amitriptyline/nortriptyline), appetite suppressants (such as diethylpropion), drugs for attention deficit disorder (such as atomoxetine, methylphenidate), apraclonidine, bupropion, buspirone, carbamazepine, cyclobenzaprine, deutetrabenazine, dextromethorphan, certain drugs for high blood pressure (such as guanethidine, methyldopa, beta blockers such as atenolol, clonidine, rauwolfia alkaloids), other MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine), metoclopramide, certain opioid medications (such as fentanyl, meperidine, methadone, tapentadol), certain drugs for Parkinson's (such as entacapone, levodopa, tolcapone), street drugs (such as LSD, mescaline), stimulants (such as amphetamines, cocaine, dopamine, epinephrine, phenylalanine), tetrabenazine, "triptan" migraine drugs (such as sumatriptan, rizatriptan), tramadol, tyrosine, tryptophan, valbenazine.
The risk of serotonin syndrome/toxicity increases if you are also taking other drugs that increase serotonin. Examples include street drugs such as MDMA/ "ecstasy," St. John's wort, certain antidepressants (including SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine), among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs.
Tell your doctor or pharmacist if you are using any of these medications before, during, or within 2 weeks after treatment with phenelzine. Tell your doctor or pharmacist if you have taken fluoxetine during at least 5 weeks before starting phenelzine. Discuss with your doctor how much time to wait between starting or stopping any of these drugs and taking phenelzine.
Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).
Check the labels on all your medicines (such as allergy, cough-and-cold products, decongestants, diet pills) because they may contain dextromethorphan, decongestants, stimulants, or ingredients that cause drowsiness. Ask your pharmacist about the safe use of those products.
Negative Interactions
4- Potential Negative Interaction
Phenelzine
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. Until more is known, people taking phenelzine should use aspartame-containing foods with caution.
AspartamePhenelzine- Shader RI, Greenblatt DJ. Phenelzine and the dream machine-ramblings and reflections. J Clin Psychopharmacol 1985;5:65.
- Potential Negative Interaction
Phenelzine
Ephedra
Ephedra contains the chemical ephedrine, which may interact with phenelzine, causing potentially dangerous changes to blood pressure. 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.
EphedraPhenelzine- 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.
- Potential Negative Interaction
Phenelzine
Scotch Broom
This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.
Scotch broom contains high levels of tyramine. Combining phenelzine and Scotch broom may cause MAOI-type reactions (diarrhoea, flushing, sweating, pounding chest, dangerous changes in blood pressure, and other symptoms). It is important for people taking phenelzine to avoid Scotch broom. People with questions about phenelzine and Scotch broom should ask their doctor.
Scotch BroomPhenelzine- Brinker F. Interactions of pharmaceutical and botanical medicines. J Naturopathic Med 1997;7(2):14-20.
- Potential Negative Interaction
Phenelzine
St. John’s Wort
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. 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.
St. John’s WortPhenelzine- St. John's wort, Hypericum perforatum. In American Herbal Pharmacopoeia and Therapeutic Compendium, ed. R Upton. Santa Cruz, CA: AHP, 1997.
Supportive Interactions
1- Replenish Depleted Nutrients
Phenelzine
Vitamin B6
This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.
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. Little is known about this interaction. People taking phenelzine should ask their doctor about monitoring vitamin B6 levels and considering supplementation.
Vitamin B6Phenelzine- Heller CA, Friedman PA. Pyridoxine deficiency and peripheral neuropathy associated with long-term phenelzine therapy. Am J Med 1983;75:887-8.