With this post, we continue our biweekly series on medications used to treat bipolar disorder and related symptoms. We have already covered lithium, along with anti-seizure and atypical antipsychotics commonly used as anti-manic medications or mood stabilizers in bipolar disorder. Last week, we introduced our coverage of SSRI (Selective Serotonin Reuptake Inhibitor) antidepressants with a post on Prozac (fluoxetine). This week, we continue our series on SSRI antidepressants with this post on Paxil (paroxetine hydrochloride).

As a group, the SSRIs share many of the same potential benefits and potential negative side effects, so we encourage you to read the Prozac post first to get up to speed about general information relating to SSRIs, including how SSRIs work and important cautions about using any antidepressant to treat depression in bipolar. In this post, we focus on Paxils unique profile in treating bipolar depression and depression in general.

Potential Benefits

Paxils potential benefits are identical to those of all SSRIs:

  • Antidepressant
  • Anti-anxiety (Paxil has a specific indication for treating social anxiety disorder but it is beneficial in many other anxiety disorders as well.)
  • Treatment of obsessive compulsive (OCD) and related disorders, often reduces irritability related to depression and anxiety

Typical Dose

Most people on Paxil take 10 to 40mg but it can be as high as 60 or 80 mg per day or up to 75 mg for Paxil CR (controlled release). Your doctor will work with you to determine an effective dosage.

Potential Side Effects

Like most medications in its class, Paxil can potentially cause any of several negative side effects. The most serious are the following:

  • Increased suicidality in children or teens: Clearly there is an increased risk of suicide and suicidal thinking in people with bipolar and depression as a whole. A large review of studies done on children and adolescents who were treated with antidepressants showed that there was a slight increase in the risk that these children would develop suicidal thoughts, compared to children taking placebo. Even with the increased risk, the rate of this side effect remains very, very low. These medications are far more likely to decrease the risk of suicide than to increase it. Careful monitoring and communication with the prescriber, especially early on in treatment with SSRI’s is essential in reducing this risk as much as possible.
  • Increased risk of mania: As mentioned earlier in this post, a person with bipolar disorder taking an antidepressant without the protection of a mood stabilizer appears to be at higher risk of shifting into mania or hypomania. While there is some indication that some antidepressants have less risk of manic switching, the risk remains present in all antidepressants. The rate of switching and the actual level of risk is not clear at this time some researchers suspect it is very high and others feel it is actually much lower than is generally presumed.
  • Agitation, increased anxiety, or worsening depression or other paradoxical effects: This is not the same as a true manic switch, and can occur in people with or without bipolar disorder who take SSRI’s. In a small group of people, these medicines seem to irritate the brain wiring rather than soothe it. This appears to be more common in children and adolescents, but can occur in a subset of adults as well. Close monitoring with your prescriber will be important in detecting this.
  • Serotonin syndrome: When combined with medicines used to treat migraine headaches known triptans, such as sumatriptan (Imitrex), or other drugs that elevate brain levels of serotonin (including the illegal drug Ecstasy), a life-threatening condition called serotonin syndrome can occur. Symptoms include restlessness, hallucinations, loss of coordination, racing heart, increased body temperature, blood pressure fluctuations, overactive reflexes, diarrhea, nausea, vomiting, coma, and possibly death.
  • Persistent pulmonary hypertension of the newborn (PPHN): There are studies showing that babies born to mothers who were taking SSRI’S in the third trimester of pregnancy have an increased likelihood of this condition. Babies born with PPHN have restricted blood flow through their heart and lungs, reducing the supply of oxygen to their bodies. This can make them very ill and increase their risk of death. If you’re pregnant or planning to become pregnant, consult with the doctor who’s managing your medications.

Other less serious side effects can include the following (Note: Many of these side effects are transient and occur when first taking these medications but do not persist.):

  • Sweating
  • Sleepiness
  • Insomnia
  • Nausea
  • Diarrhea
  • Tremor
  • Dry mouth
  • Loss of strength
  • Headache
  • Weight loss or gain
  • Dizziness
  • Restlessness
  • Mania
  • Changes in sexual function

Remember: Any antidepressant can take 2-3 weeks or even longer to become fully effective; it may take several weeks to work up to a therapeutic dose. This means that your depression may not lift for several weeks. I often tell patients that however they feel in the first two weeks is unlikely to be how they feel in a month so if they are feeling some early side effects, hold on because they will likely get better. Patience is important in getting these medications to work, but if you have any concerns about how you are feeling, you should contact your doctor. You will most likely have a follow-up visit with your doctor within a month or less of starting the medications; this is a good time frame for checking in to see if benefits have started or if side effects have faded or persisted.

Paxil has a reputation for causing more sedation and weight gain than the other SSRIs. In my practice, I have certainly seen evidence of this, However, Paxil is a powerful and effective antidepressant and anti-anxiety medication, and I do use it frequently. Paxil has a specific FDA indication for social anxiety, and I have found it to be extremely helpful in people with this condition even with severe symptoms. Social anxiety can co-exist with bipolar disorder.

I avoid using it first line in children, primarily because it was one of the first SSRIs that was found to have some increased risk of suicidal thoughts in children.

For more about Paxil, visit GlaxoSmithKlines PaxilCR page.

If you’ve taken any form of Paxil for bipolar depression or are a doctor who has prescribed it, please share your experiences, insights, and observations.