Which MAO inhibitor is commonly used as an antidepressant?

• A. Tranylcypromine
• B. Phenelzine
• C. Selegiline
• D. All of the above

Answer: (D)

Several monoamine oxidase inhibitors (MAOIs) are recognized for their effectiveness as antidepressants. Tranylcypromine is noted for its stimulating effects, making it particularly useful in cases of depression with significant fatigue. Phenelzine is beneficial for its broader utility, often used when patients have atypical features in their depression or anxiety disorders. Selegiline, typically used at lower doses for Parkinson's disease, can also serve as an antidepressant, especially in its transdermal formulation, which allows for lower risk of dietary restrictions associated with other MAOIs.

The option that states all of the above reflects the reality that each of these medications can be utilized in the treatment of depression, emphasizing the versatility of MAO inhibitors in psychiatric practice. Understanding this spectrum of usage is important as it allows healthcare providers to tailor treatments based on individual patient profiles and needs.