**Core Concept**
Panic disorder is a chronic condition characterized by recurring panic attacks, and long-term management involves pharmacotherapy to prevent or reduce the frequency of these attacks. Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants that have been found effective in treating panic disorder by increasing serotonin levels in the brain.

**Why the Correct Answer is Right**
SSRIs, particularly paroxetine (an SSRI), have been found to be effective in treating panic disorder by increasing the levels of serotonin in the synaptic cleft. This is achieved by inhibiting the reuptake of serotonin by the presynaptic neuron, allowing more serotonin to be available for binding to postsynaptic receptors. The increase in serotonin levels in the brain helps to reduce the symptoms of panic disorder, such as anxiety and fear.

**Why Each Wrong Option is Incorrect**
**Option A:** Benzodiazepines, such as alprazolam, are effective in the short-term management of panic disorder but are not recommended for long-term use due to the risk of dependence and withdrawal symptoms.

**Option B:** Tricyclic antidepressants, such as imipramine, are effective in treating panic disorder but are not typically considered first-line due to their side effect profile and the availability of safer alternatives like SSRIs.

**Option C:** Monoamine oxidase inhibitors (MAOIs), such as phenelzine, are effective in treating panic disorder but are not typically considered first-line due to dietary restrictions and the risk of hypertensive crises.

**Clinical Pearl / High-Yield Fact**
When choosing a medication for the long-term management of panic disorder, consider the potential for side effects, the risk of dependence, and the availability of safer alternatives like SSRIs.

**Correct Answer: C. Imipramine. Imipramine is a tricyclic antidepressant that is effective in treating panic disorder, although it is not typically considered first-line due to its side effect profile.