Both Paxil (paroxetine) and Zoloft (sertraline) work well for panic disorder, and both are classified as SSRIs, or selective serotonin reuptake inhibitors. Both are well-tolerated and not as activating (induce agitation and anxiety) as Prozac (fluoxetine), another SSRI. In addition, Paxil and Zoloft are not as activating as the SNRIs, such as Effexor.
Clinically, I like prescribing Zoloft, as it has a longer half-life than Paxil. Paxil has a short half-life, so it often requires twice daily dosing, which is difficult for patients to adhere to. When dosing Paxil only once daily, patients can sometime get inter-dose withdrawal symptoms, as the Paxil dose seems to wear off before the next dose. Also, when you miss a dose of Paxil, you can get severe withdrawal symptoms that feel like you have a bad case of the flu.
Zoloft just requires once daily dosing, and it is easy to dose. If you miss a dose if Zoloft, you don’t get the more severe withdrawal symptoms that you see in missing a dose of Paxil. Many primary care physicians prescribe Zoloft for anxiety, given the above advantages of once daily dosing, ease of dosing, well tolerated in patients, and discontinuance or missing doses has fewer withdrawal symptoms.
As a class, the SSRIs are relatively well tolerated and effective for panic disorder. Other SSRIs include Zoloft, Paxil, Prozac, Celexa, and Lexapro. When first starting an SSRI, your doctor may add a benzodiazepine such as Ativan or Klonopin, as the SSRIs take several weeks to work for anxiety. The benzodiazepines work almost immediately for reducing anxiety symptoms. In addition, the benzodiazepines address any activation that may emerge from the initiation of the SSRI. Once the SSRI kicks in weeks later for reducing the anxiety, then the benzodiazepine can be tapered and discontinued. SNRIs are also prescribed for panic disorder, but I tend to avoid the SNRIs, as they seem to be more activating than the SSRIs.