Paxil® (paroxetine hydrochloride)
What is Paxil?
Paxil (paroxetine hydrochloride) and Paxil CR are antidepressant medications also used to treat anxiety disorders. Paxil was introduced into the United States in early 1993. They are members of the SSRI (selective serotonin reuptake inhibitor) family (along with Zoloft and Prozac). These medications are effective in alleviating the symptoms of major depression without causing some of the harmful side effects caused by the older tricyclic antidepressants (TCAs). Paxil is also approved for the treatment of anxiety disorders, including generalized anxiety disorder (GAD), panic disorder, post-traumatic stress disorder (PTSD), social anxiety disorder, and obsessive-compulsive disorder (OCD).
What does Paxil treat?
Depression and anxiety disorders are biologically based disorders, although social factors may contribute to these illnesses. Depression is associated with decreased activity of neurotransmitters in the brain (particularly serotonin and norepinephrine). These chemical messengers help regulate several functions and thoughts, including mood. Paxil blocks the reabsorption of serotonin and normalizes the brain’s chemical supply.
What are the advantages of Paxil over other antidepressants?
Paxil is as effective in relieving depression as TCAs such as imipramine. However, Paxil causes fewer adverse cardiovascular and anticholinergic effects (dry mouth, constipation, blurred vision, urinary retention) than the older TCAs. It does not usually cause drowsiness or low blood pressure. Paxil has no active metabolites and leaves one’s system 24 hours after it enters.
Who can benefit from taking Paxil?
Paxil is equally effective in elderly depressed patients as it is in younger patients. Paxil is effective in the treatment of anxiety which accompanies depression in some people. Those experiencing lethargy at the beginning of treatment can also take Paxil with positive results because Paxil does not impair psychomotor function.
What is the standard dose of Paxil?
The usual dose of Paxil is 20 mg taken once daily, usually in the morning. Paxil comes in either 10 mg tablets and 40 mg tablets. For the depressed elderly, the recommended starting dose is 10 mg once daily. Physicians may change the dose by 10 mg at a time and the dose should not exceed 50 mg per day (40 mg in geriatric patients). There should be a one-week interval between dose adjustments. The dose of Paxil for the anxiety disorders is generally the same as for depression, except that for patients with panic disorder it is recommended to start at 10 mg. Consumers with panic disorder often need to take 40 mg a day to feel better.
Can I take Paxil with other medications?
Paxil should not be used while taking any MAOI (monoamine oxidase inhibitor) medication. The interaction between the two could produce fatal results. Therefore, there should be a fourteen-day interval between stopping the MAOI and starting Paxil, or vice versa.
Patients with kidney or liver dysfunction should take Paxil with caution. Other combinations of medications require consultation with your doctor. Alcohol consumption is best avoided while one is taking Paxil. There are some potentially problematic interactions between Paxil and other drugs such as tricyclic antidepressants and beta-blockers.
What are the most common side effects of Paxil?
For the most part, the side effects of Paxil are mild and brief. The major side effect of Paxil is nausea, which can be reduced by taking Paxil with food. Paxil CR has a lower risk of nausea than Paxil. Side effects may include drowsiness, asthenia (lack of physical strength) tremors, nervousness, dizziness, insomnia, weight gain, sweating, ejaculatory delay, and other male genital dysfunction. Only a small percentage of people have had to discontinue their use of Paxil because of side effects. Both men and women commonly experience difficulty having an orgasm while on Paxil. Also, patients who stop taking Paxil abruptly often experience dizziness, nausea, vertigo and shock-like sensations. Therefore, slow tapering is recommended.
Women who become pregnant or who are nursing an infant should discuss with their doctors the effects of Paxil. People with kidney or liver dysfunction should use Paxil with caution.
How soon will I feel better?
Some people will notice improvements within a week or two, but it may take up to six weeks for the full therapeutic effect to be realized. Depressed mood, concentration problems, and slowed activity may improve in the first week, sleep disturbances within the second week.
How long should I stay on Paxil?
Paxil should be continued as directed by the prescribing physician. Paxil is effective in the treatment of both short-term and long-term depression, and it can be beneficial in preventing relapse into depression. Studies have shown that Paxil is easily tolerated for up to four years. It is important to be in close communication with the prescribing physician, and to promptly report any unusual or distressing symptoms or side effects.
For further information please contact the pharmaceutical company listed below.
One Franklin Plaza
P.O Box 7929
Philadelphia, PA 19101
Paxil Rx Assistance Program
Increase in the Risk of Birth Defects
Early results of new studies show that paroxetine increases the risk of birth defects, particularly heart defects, when women take it during the first three months of pregnancy. Paroxetine should usually not be taken during pregnancy, but for some women who have already been taking paroxetine, the benefits of continuing paroxetine may be greater than the potential risk to the baby. Women taking paroxetine who are pregnant, think they may be pregnant, or plan to become pregnant should talk to their physicians about the potential risks of taking paroxetine during pregnancy.
The early results of two studies showed that women who took paroxetine (Paxil) during the first three months of pregnancy were about one and a half to two times as likely to have a baby with a heart defect as women who received other antidepressants, and women in the general population. Most of the heart defects in these studies were not life-threatening, and happened mainly in the inside walls of the heart muscle where repairs can be done if needed (atrial and ventricular septal defects). Sometimes these septal defects resolve without treatment. In one of the studies, the risk of heart defects in babies whose mothers had taken paroxetine early in pregnancy was 2%, compared to a 1% risk in the whole population. In the other study, the risk of heart defects in babies whose mothers had taken paroxetine in the first three months of pregnancy was 1.5%, compared to 1% in babies whose mothers had taken other antidepressants in the first three months of pregnancy. This study also showed that women who took paroxetine in the first three months of pregnancy were about twice as likely to have a baby with any birth defect as women who took other antidepressants.
The FDA is currently in the process of gathering additional data to better understand these observations.
Suicidal Thoughts or Actions in Children and Adults
Patients with depression or other mental illnesses often think about or attempt suicide. Closely watch anyone taking antidepressants, especially early in treatment or when the dose is changed. Patients who become irritable or anxious, or have new or increased thoughts of suicide or other changes in mood or behavior (or their care givers) should contact their healthcare professional right away.
Taking antidepressants may increase suicidal thoughts and actions in about 1 out of 50 people 18 years or younger. Although paroxetine is prescribed for children, FDA has not approved paroxetine for use in children.
Several recent scientific publications report the possibility of an increased risk for suicidal behavior in adults who are being treated with antidepressant medications. Even before these reports became available, FDA began a complete review of all available data to determine whether there is an increased risk of suicidal thinking or behavior in adults being treated with antidepressant medications. It is expected that this review will take a year or longer to complete. In the meantime, FDA is highlighting that adults being treated with antidepressant medication, particularly those being treated for depression, should be watched closely for worsening of depression and for increased suicidal thinking or behavior.
This information reflects FDA’s preliminary analysis of data concerning this drug. FDA is considering, but has not reached a final conclusion about, this information.
Reviewed by Jack Gorman, M.D., Chair NAMI Scientific Council, Sept 2002