The generic name for the brand-name medication Marplan is isocarboxazid. It belongs to a class of antidepressants known as monoamine oxidase inhibitors, or MAOIs. While once a more common treatment for depression, its use is now typically reserved for cases where patients have not responded to other, newer types of antidepressants due to its potentially serious side effects and dietary restrictions.
How Isocarboxazid Works
Isocarboxazid functions by inhibiting the activity of monoamine oxidase, an enzyme found in the body that breaks down specific neurotransmitters. By blocking this enzyme, isocarboxazid increases the levels of mood-regulating neurotransmitters in the brain, including serotonin, norepinephrine, and dopamine. This process helps to correct the chemical imbalances believed to cause depression.
The Role of MAOIs in Treatment
As a non-selective and irreversible MAOI, isocarboxazid blocks both types of the monoamine oxidase enzyme, MAO-A and MAO-B. Its non-selectivity necessitates precautions, unlike newer antidepressants like SSRIs that have a more targeted effect.
Clinical Use and Indications
Marplan is used to treat depression. It is often prescribed for patients who have not responded to other antidepressants and may also be used for depressive symptoms with anxiety, panic, and phobic symptoms.
Significant Risks and Adverse Effects
Using isocarboxazid carries significant risks requiring careful medical supervision and patient education.
Hypertensive Crises
A major risk is a hypertensive crisis, a rapid and dangerous increase in blood pressure. This can be life-threatening and triggered by interactions with tyramine-rich foods or certain medications.
Foods high in tyramine to avoid:
- Aged or fermented cheeses
- Cured or smoked meats and fish
- Fava bean pods
- Certain alcoholic beverages
- Soy sauce and yeast extracts
- Overripe fruits
Drug Interactions
Isocarboxazid interacts with many medications, which can lead to serious consequences. A wash-out period is needed when switching between Marplan and other antidepressants.
Key drug interactions to avoid:
- Other antidepressants: Especially SSRIs, tricyclics, and other MAOIs (risk of serotonin syndrome).
- Pain medications: Such as meperidine and tramadol.
- Stimulants and decongestants: Including diet pills and pseudoephedrine.
- CNS depressants: Including narcotics and alcohol.
Boxed Warning for Suicidality
Like other antidepressants, isocarboxazid carries an FDA boxed warning about increased suicidal thoughts and behaviors in young people. Monitoring for mood or behavior changes is essential, particularly at the start of treatment or dose adjustments.
Common Side Effects
Common side effects may include dizziness, headache, dry mouth, constipation or nausea, drowsiness or insomnia, and tremors.
Comparison of Isocarboxazid (Marplan) and SSRIs
Comparing isocarboxazid with typical first-line SSRIs clarifies its use as a second-line treatment.
| Feature | Isocarboxazid (Marplan) | Selective Serotonin Reuptake Inhibitor (SSRI) |
|---|---|---|
| Drug Class | Monoamine Oxidase Inhibitor (MAOI) | Selective Serotonin Reuptake Inhibitor |
| Typical Use | Refractory depression | First-line treatment for major depression |
| Mechanism of Action | Inhibits monoamine oxidase, increasing serotonin, norepinephrine, and dopamine. | Selectively blocks serotonin reuptake. |
| Dietary Restrictions | Severe restrictions on high-tyramine foods. | Few to no dietary restrictions. |
| Drug Interactions | Numerous and potentially fatal interactions. | Significant interactions, but generally fewer than MAOIs. |
| Common Side Effects | Dizziness, headache, dry mouth, drowsiness. | Nausea, headache, insomnia, sexual dysfunction. |
Conclusion
In summary, the generic name for Marplan is isocarboxazid. This MAOI antidepressant is primarily used for severe depression unresponsive to other treatments. The necessity of strict dietary restrictions, the risk of dangerous drug interactions, and the potential for hypertensive crisis highlight the need for close medical supervision. Discuss all benefits and risks with a healthcare provider before starting this medication. For more information, visit the {Link: NIH website https://www.ncbi.nlm.nih.gov/books/NBK548518/}.
