"Since minocycline has an anti-inflammatory effect at low doses, the improvement likely occurs through reducing inflammation. It is a different mechanism than clonazepam."
— Luciane Gargaglioni, project coordinator

Repurposed Antibiotic Shows Promise for Panic Attacks

A new study suggests that minocycline, an antibiotic commonly used for bacterial infections, may significantly reduce panic attack symptoms—at doses lower than those used for treating infection.

Supported by FAPESP and conducted at São Paulo State University (UNESP) and the Federal University of Rio de Janeiro (UFRJ), the research was published in Translational Psychiatry.

Key Findings

In Mice

In an experimental model that used CO₂ inhalation to induce panic attacks, mice treated with minocycline for 14 days prior showed a marked reduction in panic-related responses. Researchers also observed a decrease in microglial density in the locus coeruleus six hours after CO₂ exposure.

In Humans

The study involved 49 patients with panic disorder. Participants inhaled air enriched with 35% CO₂ before and after seven days of treatment with either clonazepam or minocycline. Psychiatrists measured anxiety symptoms throughout the process.

Patients who took minocycline experienced reduced intensity of panic attacks triggered by CO₂ inhalation. Additionally, they showed:

Decreased levels of pro-inflammatory cytokines (IL-2sRα, IL-6, TNFα)
Increased levels of the anti-inflammatory cytokine IL-10

A Different Mechanism

Minocycline’s effect is attributed to its anti-inflammatory action on microglia, a type of immune cell in the brain. This is a completely different pathway than clonazepam, which works by potentiating GABA receptors.

"In our experimental model, mice treated with minocycline showed a reduction in one of the panic-inducing responses. In humans, treatment reduced the intensity of panic attacks triggered by CO₂ inhalation."
— Beatriz de Oliveira, first author

Because of its distinct mechanism, minocycline may offer an alternative for the roughly 50% of patients who do not respond to standard psychiatric medications.

Next Steps

While the results are promising, further studies are necessary. Because minocycline is already approved for other medical uses, clinical trials could proceed directly to Phase 2, potentially speeding up the path to a new treatment option for panic disorder.