Citalopram is not an MAOI. It belongs to a completely different class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). The two drug classes work through different mechanisms, carry different side effect profiles, and should never be taken together.
How Citalopram Works vs. How MAOIs Work
Citalopram, sold under the brand name Celexa, increases serotonin levels in the brain by blocking nerve cells from reabsorbing serotonin after it’s been released. This leaves more serotonin available in the gaps between nerve cells, which helps regulate mood. It targets serotonin specifically, which is why the class is called “selective.”
MAOIs take a broader approach. They block an enzyme called monoamine oxidase, which normally breaks down several brain chemicals at once: serotonin, dopamine, and norepinephrine. By disabling that cleanup enzyme, MAOIs allow all three chemicals to build up. This makes them effective for depression, but it also means they affect more systems in the body and come with stricter dietary restrictions (certain aged and fermented foods can trigger dangerous blood pressure spikes when combined with MAOIs).
The FDA-approved MAOIs for depression are a small group:
- Isocarboxazid (Marplan)
- Phenelzine (Nardil)
- Tranylcypromine (Parnate)
- Selegiline (Emsam), available as a skin patch
If your medication isn’t on that list, it’s not an MAOI. Citalopram is nowhere near this category.
Why Citalopram and MAOIs Can’t Be Combined
Even though citalopram isn’t an MAOI, the two are closely linked in prescribing warnings because taking them together is dangerous. Both increase serotonin levels, but through different pathways. When combined, serotonin can spike to toxic levels, triggering a condition called serotonin syndrome.
Serotonin syndrome is a potentially life-threatening emergency. It produces a characteristic triad of symptoms: neuromuscular excitation (involuntary muscle jerking, exaggerated reflexes, tremor, rigidity), autonomic changes (rapid heart rate, sweating, flushing, dilated pupils, fever), and altered mental status (agitation, confusion, anxiety). Cases involving an MAOI tend to be more severe and are more likely to lead to serious outcomes, including death. Fatal cases are typically associated with dangerously high body temperature and seizures.
This isn’t a minor drug interaction warning. It’s one of the most consistently emphasized contraindications in psychiatry.
The 14-Day Washout Rule
If you’re switching between citalopram and an MAOI in either direction, the FDA requires a minimum 14-day gap. That means at least 14 days must pass after stopping an MAOI before starting citalopram, and at least 14 days after stopping citalopram before starting an MAOI. This washout period gives your body enough time to fully clear the first medication so the two drugs never overlap in your system.
This timeline matters even though you might feel like the first medication has worn off sooner. Drug traces can linger in your body longer than their mood effects do, and even residual amounts can interact. Skipping or shortening the washout period puts you at risk for serotonin syndrome.
Signs of Serotonin Syndrome to Watch For
If you’re transitioning between these medications, or if you’ve accidentally overlapped them, the early warning signs of serotonin syndrome include anxiety, agitation, restlessness, shivering, and muscle twitching. More advanced symptoms include confusion, rapid heart rate, heavy sweating, muscle rigidity, and fever. Involuntary jerking movements (clonus) and exaggerated reflexes are considered key diagnostic signs.
Symptoms typically develop within hours of the problematic dose, not days. They can progress quickly from mild restlessness to a medical emergency, so early recognition matters. If you notice a cluster of these symptoms after any change in your antidepressant regimen, treat it as urgent.