Bipolar Disorder Medication Spotlight: Monoamine Oxidase Inhibitors (MAOI’s)

By Candida Fink MD
August 21, 2009

With this post, we continue our sort-of-biweekly series on medications used to treat bipolar disorder and related symptoms. Two weeks ago, we covered an older class of antidepressants that are still sometimes used – Tricyclics. This week, we turn our attention to another older classes of antidepressants – Monoamine Oxidase Inhibitors or MAOI’s, for short.

Medications in this group work differently from SSRI’s(including Prozac and Paxil), SSNRI’s(including Effexor and Cymbalta), and Wellbutrin. While MAOI’s have fallen out of favor since the introduction of the newer generation of antidepressants, they remain effective and may be useful alternatives in some cases.

Monoamine Oxidase Inhibitors (MAOI’s)

Monoamine Oxidase Inhibitorsare the earliest antidepressants, developed in the 1950s. They work by preventing the action of an enzyme that breaks down norepinephrine, serotonin, and dopamine, along with a number of related brain chemicals, resulting in an increase in the levels of these chemicals in the brain. MAO inhibitors include the following:

Phenelzine (Nardil)
Tranylcypromine (Parnate)
Isocarboxazid (Marplan)
Selegiline (Emsam)

Emsam is a second generation MAOI that has been released in recent years. The other formulations are much older and have fallen out of favor with most prescribers. Emsam is provided as a skin patch that you apply to your arm, torso, or thigh. The medication passes slowly and gradually through your skin into your bloodstream. By absorbing the medication more slowly, patients may be able to avoid some of the dietary restrictions that often accompany MAOI’s (as explained later in this post).

The main benefit of MAOI’s is the fact that they boost the three main neurotransmitters that affect mood – serotonin, norepinephrine, and dopamine. They may work more effectively on “atypical” types of depressions, as well, and can be powerfully effective antidepressants for some people. They actually have a strong track record specifically with bipolar depression that has not responded to other interventions.

The restrictions on their use over the years have been due primarily to the following three reasons:

The extensive dietary restrictions required for the older MAOI’s.
The dangerous effects of not following these restrictions.
The severe and dangerous interactions between MAOI’s and many, many other medications, including all of the SSRI’s and SNRI’s. Switching from an SSRI to an MAOI requires a number of weeks of a washout period, so that SSRI is completely removed from the system before starting the MAOI.

Like all antidepressants, MAOI’s carry a risk of manic switching and of agitation and/or suicidal ideation.

Potential Side Effects

The side-effect profile for MAOI’s dwarfs that of even the tricyclics. Possible side effects include the following:

Severe interactions with certain foods and many medications, as described in the following section
Manic switching
Agitation and suicidal ideation
Blurred vision
Constipation
Decreased sexual function
Decreased urine output
Diarrhea
Dizziness
Drowsiness, fatigue
Dry mouth
Headache
Increased appetite and weight gain
Increased sweating
Lightheadedness, especially when getting up from a lying or sitting position
Low blood pressure
Muscle twitching
Nausea, upset stomach
Restlessness
Shakiness and tremor
Sleep disturbances
Weakness

Potentially Dangerous Food and Drug Interactions

MAOI’s can have dangerous interactions with certain foods and beverages, which may result in a spike in blood pressure, possibly causing a stroke. If you take medications in this class, you may face some serious dietary restrictions and have to avoid any foods that contain a high concentration of tyramine, including the following:

Many cheeses
Pickled foods
Chocolates
Certain meats
Beer and wine (even the alcohol-free or light varieties)
Certain beans and legumes

Serious interactions may also occur with certain medications or herbal remedies, including…

Decongestants
Herbal weight-loss products
Meperidine (Demerol) and all narcotic pain relievers
St. John’s wort
Tramadol (Ultram)
All other antidepressants especially those that increase serotonin levels in the brain
Many other medications

Caution: Consult your doctor prior to adding any medications or herbal remedies to your regimen, even commonly used over-the-counter medications. This is true for all medications but especially critical if you are taking an MAOI.

MAOI’s in My Practice

I have not used MAOI’s in my practice for many years. I have not found the need to go to this level of medication given the many other choices available. MAOI’s, at this point in time, are mostly used in academic settings that handle the most complex kinds of mood disorders.

If you’ve taken any MAOI’s for bipolar depression or other conditions or are a doctor who has prescribed any of the older antidepressants in this class, please share your experiences, insights, and observations.