As with any CNS-active drug, fluoxetine has the potential to impair judgment, thinking, or motor skills. Patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain that the drug treatment does not affect them adversely.
Because of the long elimination half-lives of the parent drug and its major active metabolite, changes in dose will not be fully reflected in plasma for several weeks, affecting both strategies for titration to final dose and withdrawal from treatment. This is of potential consequence when drug discontinuation is required or when drugs are prescribed that might interact with fluoxetine and norfluoxetine following the discontinuation of fluoxetine [see Clinical Pharmacology (12.3)] .
During marketing of fluoxetine, SNRIs, and SSRIs, there have been spontaneous reports of adverse reactions occurring upon discontinuation of these drugs, particularly when abrupt, including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paresthesias such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, and hypomania. While these reactions are generally self-limiting, there have been reports of serious discontinuation symptoms. Patients should be monitored for these symptoms when discontinuing treatment with fluoxetine. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the healthcare provider may continue decreasing the dose but at a more gradual rate. Plasma fluoxetine and norfluoxetine concentration decrease gradually at the conclusion of therapy which may minimize the risk of discontinuation symptoms with this drug.
Use of SSRIs, including fluoxetine, may cause symptoms of sexual dysfunction [see Adverse Reactions (6.1)]. In male patients, SSRI use may result in ejaculatory delay or failure, decreased libido, and erectile dysfunction. In female patients, SSRI use may result in decreased libido and delayed or absent orgasm.
It is important for prescribers to inquire about sexual function prior to initiation of fluoxetine and to inquire specifically about changes in sexual function during treatment, because sexual function may not be spontaneously reported. When evaluating changes in sexual function, obtaining a detailed history (including timing of symptom onset) is important because sexual symptoms may have other causes, including the underlying psychiatric disorder. Discuss potential management strategies to support patients in making informed decisions about treatment.
The following adverse reactions are discussed in more detail in other sections of the labeling:
- Suicidal Thoughts and Behaviors in Children, Adolescents, and Young Adults [see Boxed Warning and Warnings and Precautions (5.1)]
- Serotonin Syndrome [see Warnings and Precautions (5.2)]
- Allergic Reactions and Rash [see Warnings and Precautions (5.3)]
- Screening Patients for Bipolar Disorder and Monitoring for Mania/Hypomania [see Warnings and Precautions (5.4)]
- Seizures [see Warnings and Precautions (5.5)]
- Altered Appetite and Weight [see Warnings and Precautions (5.6)]
- Abnormal Bleeding [see Warnings and Precautions (5.7)]
- Angle-Closure Glaucoma [see Warnings and Precautions (5.8)]
- Hyponatremia [see Warnings and Precautions (5.9)]
- Anxiety and Insomnia [see Warnings and Precautions (5.10)]
- QT Prolongation [see Warnings and Precautions (5.11)]
- Potential for Cognitive and Motor Impairment [see Warnings and Precautions (5.13)]
- Discontinuation Adverse Reactions [see Warnings and Precautions (5.15)]
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect or predict the rates observed in practice.
Multiple doses of fluoxetine have been administered to 10,782 patients with various diagnoses in US clinical trials. In addition, there have been 425 patients administered fluoxetine in panic clinical trials. The stated frequencies represent the proportion of individuals who experienced, at least once, a treatment-emergent adverse reaction of the type listed. A reaction was considered treatment-emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation.
In c id e n c e in Major Depressive Disorder, OCD, bulimia, and Panic Disorder placebo-controlled clinical trials (excluding data from extensions of trials) — Table 2 enumerates the most common treatment-emergent adverse reactions associated with the use of fluoxetine (incidence of at least 5% for fluoxetine and at least twice that for placebo within at least 1 of the indications) for the treatment of Major Depressive Disorder, OCD, and bulimia in US controlled clinical trials and Panic Disorder in US plus non-US controlled trials. Table 4 enumerates treatment-emergent adverse reactions that occurred in 2% or more patients treated with fluoxetine and with incidence greater than placebo who participated in US Major Depressive Disorder, OCD, and bulimia controlled clinical trials and US plus non-US Panic Disorder controlled clinical trials. Table 3 provides combined data for the pool of studies that are provided separately by indication in Table 2.
|Percentage of Patients Reporting Event|
|Major Depressive Disorder||OCD||Bulimia||Panic Disorder|
|Body System/ Adverse Reaction||Fluoxetine (N=1728)||Placebo (N=975)||Fluoxetine (N=266)||Placebo (N=89)||Fluoxetine (N=450)||Placebo (N=267)||Fluoxetine (N=425)||Placebo (N=342)|
|Body as a Whole|
|Skin and Appendages|
|Abnormal Ejaculation 3||7||7||2||1|
1 Incidence less than 1%.
2 Includes US data for Major Depressive Disorder, OCD, Bulimia, and Panic Disorder clinical trials, plus non-US data for Panic Disorder clinical trials. 3 Denominator used was for males only (N=690 fluoxetine Major Depressive Disorder; N=410 placebo Major Depressive Disorder; N=116 fluoxetine OCD; N=43 placebo OCD; N=14 fluoxetine bulimia; N=1 placebo bulimia; N=162 fluoxetine panic; N=121 placebo panic).
|Percentage of Patients Reporting Event|
|Major Depressive Disorder, OCD, Bulimia and Panic Disorder Combined|
|Body System/ Adverse Reaction||Fluoxetine (N=2869)||Placebo (N=1673)|
|Body as a Whole|
|Metabolic and Nutritional Disorders|
|Skin and Appendages|
1 Incidence less than 1%. 2 Includes US data for Major Depressive Disorder, OCD, Bulimia, and Panic Disorder clinical trials, plus non-US data for Panic Disorder clinical trials.
Associated with discontinuation in Major Depressive Disorder, OCD, Bulimia, and Panic Disorder placebo-controlled clinical trials (excluding data from extensions of trials) — Table 4 lists the adverse reactions associated with discontinuation of fluoxetine treatment (incidence at least twice that for placebo and at least 1% for fluoxetine in clinical trials collecting only a primary reaction associated with discontinuation) in Major Depressive Disorder, OCD, Bulimia, and Panic Disorder clinical trials, plus non-US Panic Disorder clinical trials.
|Major Depressive Disorder, OCD, Bulimia, and Panic Disorder Combined (N=1533)||Major Depressive Disorder (N=392)||OCD (N=266)||Bulimia (N=450)||Panic Disorder (N=425)|
|Anxiety (1%)||–||Anxiety (2%)||–||Anxiety (2%)|
|–||Nervousness (1%)||–||–||Nervousness (1%)|
1 Includes US Major Depressive Disorder, OCD, Bulimia, and Panic Disorder clinical trials, plus non-US Panic Disorder clinical trials.
O the r adverse reactions in pediatric patients (children and adolescents) — Treatment-emergent adverse reactions were collected in 322 pediatric patients (180 fluoxetine-treated, 142 placebo-treated). The overall profile of adverse reactions was generally similar to that seen in adult studies, as shown in Tables 3 and 4. However, the following adverse reactions (excluding those which appear in the body or footnotes of Tables 3 and 4 and those for which the COSTART terms were uninformative or misleading) were reported at an incidence of at least 2% for fluoxetine and greater than placebo: thirst, hyperkinesia, agitation, personality disorder, epistaxis, urinary frequency, and menorrhagia.
The most common adverse reaction (incidence at least 1% for fluoxetine and greater than placebo) associated with discontinuation in 3 pediatric placebo-controlled trials (N=418 randomized; 228 fluoxetine-treated; 190 placebo-treated) was mania/hypomania (1.8% for fluoxetine-treated, 0% for placebo-treated). In these clinical trials, only a primary reaction associated with discontinuation was collected.
Male and female sexual dysfunction with SSRIs — Although changes in sexual desire, sexual performance, and sexual satisfaction often occur as manifestations of a psychiatric disorder, they may also be a consequence of pharmacologic treatment. In particular, some evidence suggests that SSRIs can cause such untoward sexual experiences. Reliable estimates of the incidence and severity of untoward experiences involving sexual desire, performance, and satisfaction are difficult to obtain, however, in part because patients and healthcare providers may be reluctant to discuss them. Accordingly, estimates of the incidence of untoward sexual experience and performance, cited in product labeling, are likely to underestimate their actual incidence. In patients enrolled in US Major Depressive Disorder, OCD, and bulimia placebo-controlled clinical trials, decreased libido was the only sexual side effect reported by at least 2% of patients taking fluoxetine (4% fluoxetine, <1% placebo). There have been spontaneous reports in women taking fluoxetine of orgasmic dysfunction, including anorgasmia.
There are no adequate and well-controlled studies examining sexual dysfunction with fluoxetine treatment.
Symptoms of sexual dysfunction occasionally persist after discontinuation of fluoxetine treatment.
Priapism has been reported with all SSRIs.
While it is difficult to know the precise risk of sexual dysfunction associated with the use of SSRIs, healthcare providers should routinely inquire about such possible side effects.
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