本品可引起轻微而短暂的不良反应。常见的有轻度口干、恶心、厌 食、便秘、头疼、震颤、乏力、失眠和性功能障碍。偶见神 经性水肿、荨麻疹、体位性低血压。罕见锥体外系反应的报道。
Paxil(Paroxetine)
Paroxetine, sold under the brand names Paxil and Seroxat among others, is an antidepressant of the selective serotonin reuptake inhibitor(SSRI) class.[5] 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.[5] It has also been used in the treatment of hot flashes due to menopause and premature ejaculation.[6][5] It is taken by mouth.[5]
Common side effects include drowsiness, dry mouth, loss of appetite, sweating, trouble sleeping, and sexual dysfunction.[5] Serious side effectsmay include suicide in those under the age of 25, serotonin syndrome, and mania.[5] While rate of side effects appear similar compared to other SSRIs and SNRIs, antidepressant discontinuation syndromes may occur more often.[7][8] Use in pregnancy is not recommended while use during breastfeeding is relatively safe.[9] It believed to work by blocking the re-uptake of the chemical serotonin by neurons in the brain.[5]
Paroxetine was approved for medical use in the United States in 1992 and initially sold by GlaxoSmithKline.[5][10] It is currently avaliable as a generic medication.[11] A month supply in the United Kingdom costs the NHS about 1.10 £ per month as of 2019.[11] In the United States the wholesale cost of this amount is about 2.40 USD.[12] In 2016, it was the 64th most prescribed medication in the United States, with more than 12 million prescriptions.[13] The United States Department of Justice fined GlaxoSmithKline $3 billion in 2012, for withholding data, unlawfully promoting use in those under 18, and preparing an article that misleadingly reported the effects of paroxetine in adolescent with depression following its clinical trial study 329.[14][15][16]
Medical uses
Paroxetine is primarily used to treat major depressive disorder, obsessive-compulsive disorder, post-traumatic stress disorder, social anxiety disorder, panic disorder, agoraphobia, generalized anxiety disorder, premenstrual dysphoric disorder and menopausal hot flashes.[17][18]
Depression
A variety of meta analyses have been conducted to evaluate the efficacy of paroxetine in depression. They have variously concluded that paroxetine is superior or equivalent to placebo and that it is equivalent or inferior to other antidepressants.[19][20][21] Despite this, there was no clear evidence that paroxetine was better or worse compared with other antidepressants at increasing response to treatment at any time point.[22]
Anxiety disorders
Paroxetine was the first antidepressant approved in the United States for the treatment of panic disorder.[23][page needed] Several studies have concluded that paroxetine is superior to placebo in the treatment of panic disorder.[24][25]
Paroxetine has demonstrated efficacy for the treatment of social anxiety disorder in adults and children.[26][27] It is also beneficial for people with co-occurring social anxiety disorder and alcohol use disorder.[28] It appears to be similar to a number of other SSRIs.[29]
Paroxetine is used in the treatment of obsessive-compulsive disorder.[30] Comparative efficacy of paroxetine is equivalent to that of clomipramine and venlafaxine.[31][32] Paroxetine is also effective for children with obsessive-compulsive disorder.[33]
Paroxetine is approved for treatment of PTSD in the United States, Japan and Europe.[34][35][36] In the United States it is approved for short term use.[35]
Paroxetine has also FDA approval for Generalized anxiety disorder.[37]
Menopausal hot flashes
On June 28, 2013, the U.S. Food and Drug Administration approved low-dose paroxetine for the treatment of moderate-to-severe vasomotor symptoms such as hot flashes and night sweats associated with menopause.[6] At the low dose used for menopausal hot flashes, side effects are similar to placebo and dose tapering is not required for discontinuation.[38]
Adverse effects
Common side effects include drowsiness, dry mouth, loss of appetite, sweating, trouble sleeping, and sexual dysfunction.[5] Serious side effects may include suicide in those under the age of 25, serotonin syndrome, and mania.[5] While rate of side effects appear similar compared to other SSRIs and SNRIs, antidepressant discontinuation syndromes may occur more often.[39][40] Use in pregnancy is not recommended while use during breastfeeding is relatively safe.[9]
Paroxetine shares many of the common adverse effects of SSRIs, including (with the corresponding rates seen in people treated with placebo in parentheses): nausea 26% (9%), diarrhea 12% (8%), constipation 14% (9%), dry mouth 18% (12%), somnolence 23% (9%), insomnia 13% (6%), headache 18% (17%), hypomania 1% (0.3%), blurred vision 4%(1%), loss of appetite 6% (2%), nervousness 5% (3%), paraesthesia 4% (2%), dizziness 13% (6%), asthenia (weakness; 15% (6%)), tremor 8% (2%), sweating 11% (2%), and sexual dysfunction (≥10% incidence).[4] Most of these adverse effects are transient and go away with continued treatment. Central and peripheral 5-HT3 receptor stimulation is believed to result in the gastrointestinal effects observed with SSRI treatment.[41] Compared to other SSRIs, it has a lower incidence of diarrhea, a higher incidence of anticholinergic effects (e.g., dry mouth, constipation, blurred vision, etc.), sedation/somnolence/drowsiness, sexual side effects, and weight gain.[42]
Due to reports of adverse withdrawal reactions upon terminating treatment, the Committee for Medicinal Products for Human Use (CHMP) at the European Medicines Agencyrecommends gradually reducing over several weeks or months if the decision to withdraw is made.[43] See also Discontinuation syndrome (withdrawal).
Mania or hypomania may occur in 1% of patients with depression and up to 12% of patients with bipolar disorder.[44] This side effect can occur in individuals with no history of mania but it may be more likely to occur in those with bipolar or with a family history of mania.[45]
Suicide
Like other antidep
ressants, paroxetine may increase the risk of suicidal thinking and behaviour in children and adolescents.[46][47] The FDA conducted a statistical analysis of paroxetine clinical trials in children and adolescents in 2004 and found an increase in suicidality and ideation as compared to placebo, which was observed in trials for both depression and anxiety disorders.[48] In 2015 a paper published in The BMJ that reanalysed the original case notes argued that in Study 329,[49] assessing paroxetine and imipramine against placebo in adolescents with depression, the incidence of suicidal behavior had been under-reported and the efficacy exaggerated for paroxetine.[50]
Sexual dysfunction
Sexual dysfunction, including loss of libido, anorgasmia, lack of vaginal lubrication, and erectile dysfunction, is one of the most commonly encountered adverse effects of treatment with paroxetine and other SSRIs. While early clinical trials suggested a relatively low rate of sexual dysfunction, more recent studies in which the investigator actively inquires about sexual problems suggest that the incidence is higher than 70%.[51] Symptoms of sexual dysfunction have been reported to persist after discontinuing SSRIs, although this is thought to be occasional.[52][53][54]
Pregnancy
The American College of Obstetricians and Gynecologists recommends that for pregnant women and women planning to become pregnant, "treatment with all SSRIs or selective norepinephrine reuptake inhibitors or both during pregnancy be individualized and paroxetine use among pregnant women or women planning to become pregnant be avoided, if possible".[55] It may be associated with a slightly increased risk of birth defects.[55][56]
According to the prescribing information, "epidemiological studies have shown that infants born to women who had first trimester paroxetine exposure had an increased risk of cardiovascular malformations, primarily ventricular and atrial septal defects (VSDs and ASDs). In general, septal defects range from those that are symptomatic and may require surgery to those that are asymptomatic and may resolve spontaneously. If a patient becomes pregnant while taking paroxetine, she should be advised of the potential harm to the fetus. Unless the benefits of paroxetine to the mother justify continuing treatment, consideration should be given to either discontinuing paroxetine therapy or switching to another antidepressant."[57] These conclusions are supported by multiple systematic reviews and meta-analyses that found that, on average, the use of paroxetine during pregnancy is associated with about 1.5–1.7-fold increase in congenital birth defects, in particular, heart defects.[58][59][60][61][62]
Discontinuation syndrome
Many psychoactive medications can cause withdrawal symptoms upon discontinuation from administration. Evidence has shown that paroxetine has among the highest incidence rates and severity of withdrawal syndrome of any medication of its class.[63] Common withdrawal symptoms for paroxetine include nausea, dizziness, lightheadedness and vertigo; insomnia, nightmares and vivid dreams; feelings of electricity in the body, as well as rebound depression and anxiety. Liquid formulation of paroxetine is available and allows a very gradual decrease of the dose, which may prevent discontinuation syndrome. Another recommendation is to temporarily switch to fluoxetine, which has a longer half-life and thus decreases the severity of discontinuation syndrome.[64][65][66]
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.[67][68] Along with the other SSRIs, sertraline and fluoxetine, paroxetine is considered a low-risk drug in cases of overdose.[69]
