MAO-B Inhibitors: What They Are, How They Work, and Which Ones Are Used Today

When you hear MAO-B inhibitors, a class of drugs that block the enzyme monoamine oxidase B to increase dopamine levels in the brain. Also known as dopamine-preserving agents, they’re not flashy, but they play a quiet, vital role in managing Parkinson’s disease and sometimes in slowing cognitive decline. Unlike antidepressants that target serotonin or norepinephrine, these drugs focus on one thing: keeping dopamine alive longer in the brain. That’s critical because Parkinson’s is largely about losing dopamine-producing neurons. By stopping MAO-B from breaking down dopamine, these drugs help the brain make the most of what’s left.

Two main drugs dominate this category: selegiline, an older MAO-B inhibitor often used in early-stage Parkinson’s to delay the need for levodopa, and rasagiline, a newer option with fewer dietary restrictions and a cleaner side effect profile. Both are taken as pills, usually once a day. They don’t cure Parkinson’s, but they can smooth out the early symptoms—like stiffness or slow movement—long enough to help people stay active. You won’t see dramatic improvements like with levodopa, but for many, they’re the difference between needing help with daily tasks and still managing them alone.

These drugs also show up in research for other brain-related conditions. Some studies suggest they might slow the progression of mild cognitive impairment, though that’s still being tested. They’re not used for depression like older MAO inhibitors (those are different and come with strict food rules), and they don’t interact with tyramine-rich foods the same way. That’s a big reason why doctors prefer them today: fewer surprises, easier to live with.

What you’ll find in the articles below isn’t just theory. You’ll see real comparisons—how selegiline stacks up against rasagiline, how they fit with other Parkinson’s meds like levodopa or dopamine agonists, and what patients actually report after months of use. You’ll also find posts that tie into related topics: how Donepezil helps with dementia, why statins like pitavastatin matter for metabolic health, and how drugs like Montelukast and Bupropion work in entirely different systems. All of it connects back to one truth: brain chemistry is messy, and sometimes the smallest tweak—a single enzyme blocked—can make a real difference in someone’s life.