In connection with a Glaxo spokespersons statement that withdrawal reactions occur only in 0.2% of patients and are "mild and short-lived", the International Federation of Pharmaceutical Manufacturers Associations said GSK had breached two of the Federations codes of practice.Paroxetine prescribing information posted at GlaxoSmithKline has been updated related to the occurrence of a discontinuation syndrome, including serious discontinuation symptoms. Overdose
Acute overdosage is often manifested by emesis, lethargy, ataxia, tachycardia, and seizures. Plasma, serum, or blood concentrations of paroxetine may be measured to monitor therapeutic administration, confirm a diagnosis of poisoning in hospitalized patients or to aid in the medicolegal investigation of fatalities. Plasma paroxetine concentrations are generally in a range of 40–400 μg/L in persons receiving daily therapeutic doses and 200–2,000 μg/L in poisoned patients. Postmortem blood levels have ranged from 1–4 mg/L in acute lethal overdose situations. Along with the other SSRIs, sertraline and fluoxetine, paroxetine is considered a low-risk drug in cases of overdose. Interactions
Interactions with other drugs acting on the serotonin system or impairing the metabolism of serotonin may increase the risk of serotonin syndrome or neuroleptic malignant syndrome (NMS)-like reaction. Such reactions have been observed with SNRIs and SSRIs alone, but particularly with concurrent use of triptans, MAO inhibitors, antipsychotics, or other dopamine antagonists.
Paroxetine, sold under the brand names Paxil and Seroxat among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used to treat major depressive disorder, obsessive-compulsive disorder, panic disorder, social anxiety disorder, posttraumatic stress disorder, generalized anxiety disorder and premenstrual dysphoric disorder. It has also been used in the treatment of premature ejaculation and hot flashes due to menopause. It is taken by mouth.Common side effects include drowsiness, dry mouth, loss of appetite, sweating, trouble sleeping, and sexual dysfunction. Serious side effects may include suicidal thoughts in those under the age of 25, serotonin syndrome, and mania. While the rate of side effects appears similar compared to other SSRIs and SNRIs, antidepressant discontinuation syndromes may occur more often. Use in pregnancy is not recommended, while use during breastfeeding is relatively safe. It is believed to work by blocking the re-uptake of the chemical serotonin by neurons in the brain.Paroxetine was approved for medical use in the United States in 1992 and initially sold by GlaxoSmithKline. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. In 2019, it was the 78th most commonly prescribed medication in the United States, with more than 9 million prescriptions. In 2018, it was in the top 10 of most prescribed antidepressants in the United States.