Prozac Side Effects Center

Last updated on RxList: 9/26/2022
Prozac Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Prozac?

Prozac (fluoxetine) is a type of antidepressant called a selective serotonin reuptake inhibitor (SSRI) used for treating

Prozac is available in generic form.

What Are Side Effects of Prozac?

Prozac may cause serious side effects including:

Get medical help right away, if you have any of the symptoms listed above.

Possible side effects of Prozac include:

Call your doctor at once if you have the following serious side effects:

  • blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
  • low levels of sodium in the body with severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or
  • severe nervous system reaction with very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Dosage for Prozac

  • The recommended dose of Prozac is 10-80 mg daily.
  • Prozac should not be administered for at least 14 days after stopping and MAOIs should not be administered for at least 5 weeks after Prozac has been stopped.

What Drugs, Substances, or Supplements Interact with Prozac?

  • Prozac should not be taken with monoamine oxidase inhibitors (MAOI) (for example, isocarboxazid [Marplan)].

Prozac During Pregnancy and Breastfeeding

  • Use of Prozac during the third trimester of pregnancy may lead to adverse effects in the newborn.
  • Tell your doctor if you become pregnant while taking Prozac.
  • Prozac may cause heart defects or serious lung problems in a newborn if you take the medication during pregnancy. However, you may have a relapse of depression if you stop taking your antidepressant.
  • Do not start or stop taking Prozac during pregnancy without your doctor's advice.
  • Prozac passes into breast milk and may harm a nursing baby.
  • Consult your doctor before breastfeeding.

Additional Information

Some patients may experience withdrawal reactions such nausea, nervousness, and insomnia upon stopping Prozac.

Our Prozac Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

QUESTION

Depression is a(n) __________ . See Answer
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Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

  • blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
  • low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or
  • severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

Common side effects may include:

  • sleep problems (insomnia), strange dreams;
  • headache, dizziness, drowsiness, vision changes;
  • tremors or shaking, feeling anxious or nervous;
  • pain, weakness, yawning, tired feeling;
  • upset stomach, loss of appetite, nausea, vomiting, diarrhea;
  • dry mouth, sweating, hot flashes;
  • changes in weight or appetite;
  • stuffy nose, sinus pain, sore throat, flu symptoms; or
  • decreased sex drive, impotence, or difficulty having an orgasm.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

SLIDESHOW

Learn to Spot Depression: Symptoms, Warning Signs, Medication See Slideshow
Prozac Professional Information

SIDE EFFECTS

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 BOX WARNING and WARNINGS AND PRECAUTIONS]
  • Serotonin Syndrome [see WARNINGS AND PRECAUTIONS]
  • Allergic Reactions and Rash [see WARNINGS AND PRECAUTIONS]
  • Screening Patients for Bipolar Disorder and Monitoring for Mania/Hypomania [see WARNINGS AND PRECAUTIONS]
  • Seizures [see WARNINGS AND PRECAUTIONS]
  • Altered Appetite and Weight [see WARNINGS AND PRECAUTIONS]
  • Abnormal Bleeding [see WARNINGS AND PRECAUTIONS]
  • Angle-Closure Glaucoma [see WARNINGS AND PRECAUTIONS]
  • Hyponatremia [see WARNINGS AND PRECAUTIONS]
  • Anxiety and Insomnia [see WARNINGS AND PRECAUTIONS]
  • QT Prolongation [see WARNINGS AND PRECAUTIONS]
  • Potential for Cognitive and Motor Impairment [see WARNINGS AND PRECAUTIONS]
  • Discontinuation Adverse Reactions [see WARNINGS AND PRECAUTIONS]
  • Sexual Dysfunction [see WARNINGS AND PRECAUTIONS]

When using PROZAC and olanzapine in combination, also refer to the Adverse Reactions section of the package insert for Symbyax.

Clinical Trials Experience

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 PROZAC have been administered to 10,782 patients with various diagnoses in US clinical trials. In addition, there have been 425 patients administered PROZAC 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.

Incidence In Major Depressive Disorder, OCD, Bulimia, And Panic Disorder Placebo-Controlled Clinical Trials (Excluding Data From Extensions Of Trials)

Table 3 enumerates the most common treatment-emergent adverse reactions associated with the use of PROZAC (incidence of at least 5% for PROZAC 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 5 enumerates treatment-emergent adverse reactions that occurred in 2% or more patients treated with PROZAC 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 4 provides combined data for the pool of studies that are provided separately by indication in Table 3.

Table 3: Most Common Treatment-Emergent Adverse Reactions: Incidence in Major Depressive Disorder, OCD, Bulimia, and Panic Disorder Placebo-Controlled Clinical Trials1,2

Percentage of Patients Reporting Event
Major Depressive Disorder OCD Bulimia Panic Disorder
Body System/
Adverse Reaction
PROZAC
(N=1728)
Placebo
(N=975)
PROZAC
(N=266)
Placebo
(N=89)
PROZAC
(N=450)
Placebo
(N=267)
PROZAC
(N=425)
Placebo
(N=342)
Body as a Whole
  Asthenia 9 5 15 11 21 9 7 7
  Flu syndrome 3 4 10 7 8 3 5 5
Cardiovascular System
  Vasodilatation 3 2 5 - 2 1 1 -
Digestive System
  Nausea 21 9 26 13 29 11 12 7
  Diarrhea 12 8 18 13 8 6 9 4
  Anorexia 11 2 17 10 8 4 4 1
  Dry mouth 10 7 12 3 9 6 4 4
  Dyspepsia 7 5 10 4 10 6 6 2
Nervous System
  Insomnia 16 9 28 22 33 13 10 7
  Anxiety 12 7 14 7 15 9 6 2
  Nervousness 14 9 14 15 11 5 8 6
  Somnolence 13 6 17 7 13 5 5 2
  Tremor 10 3 9 1 13 1 3 1
  Libido decreased 3 - 11 2 5 1 1 2
  Abnormal dreams 1 1 5 2 5 3 1 1
Respiratory System
  Pharyngitis 3 3 11 9 10 5 3 3
  Sinusitis 1 4 5 2 6 4 2 3
  Yawn - - 7 - 11 - 1 -
Skin and Appendages
  Sweating 8 3 7 - 8 3 2 2
  Rash 4 3 6 3 4 4 2 2
Urogenital System
  Impotence3 2 - - - 7 - 1 -
  Abnormal ejaculation3 - - 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 PROZAC Major Depressive Disorder; N=410 placebo Major Depressive Disorder; N=116 PROZAC OCD; N=43 placebo OCD; N=14 PROZAC bulimia; N=1 placebo bulimia; N=162 PROZAC panic; N=121 placebo panic).

Table 4: Treatment-Emergent Adverse Reactions: Incidence in Major Depressive Disorder, OCD, Bulimia, and Panic Disorder Placebo-Controlled Clinical Trials1,2

Body System/
Adverse Reaction
Percentage of Patients Reporting Event
Major Depressive Disorder, OCD, Bulimia, and Panic Disorder Combined
PROZAC
(N=2869)
Placebo
(N=1673)
Body as a Whole
  Headache 21 19
  Asthenia 11 6
  Flu syndrome 5 4
  Fever 2 1
Cardiovascular System
  Vasodilatation 2 1
Digestive System
  Nausea 22 9
  Diarrhea 11 7
  Anorexia 10 3
  Dry mouth 9 6
  Dyspepsia 8 4
  Constipation 5 4
  Flatulence 3 2
  Vomiting 3 2
Metabolic and Nutritional Disorders
  Weight loss 2 1
Nervous System
  Insomnia 19 10
  Nervousness 13 8
  Anxiety 12 6
  Somnolence 12 5
  Dizziness 9 6
  Tremor 9 2
  Libido decreased 4 1
  Thinking abnormal 2 1
Respiratory System
  Yawn 3 -
Skin and Appendages
  Sweating 7 3
  Rash 4 3
  Pruritus 3 2
Special Senses
  Abnormal vision 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.

Associated With Discontinuation In Major Depressive Disorder, OCD, Bulimia, And Panic Disorder Placebo-Controlled Clinical Trials (Excluding Data From Extensions Of Trials)

Table 5 lists the adverse reactions associated with discontinuation of PROZAC treatment (incidence at least twice that for placebo and at least 1% for PROZAC 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.

Table 5: Most Common Adverse Reactions Associated with Discontinuation in Major Depressive Disorder, OCD, Bulimia, and Panic Disorder Placebo-Controlled Clinical Trials1

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%)
- - - Insomnia (2%) -
- Nervousness (1%) - - Nervousness (1%)
- - Rash (1%) - -
1 Includes US Major Depressive Disorder, OCD, Bulimia, and Panic Disorder clinical trials, plus non-US Panic Disorder clinical trials.

Other AdverseReactions 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 4 and 5. However, the following adverse reactions (excluding those which appear in the body or footnotes of Tables 4 and 5 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.

Other Reactions

Following is a list of treatment-emergent adverse reactions reported by patients treated with fluoxetine in clinical trials. This listing is not intended to include reactions (1) already listed in previous tables or elsewhere in labeling, (2) for which a drug cause was remote, (3) which were so general as to be uninformative, (4) which were not considered to have significant clinical implications, or (5) which occurred at a rate equal to or less than placebo.

Reactions are classified by body system using the following definitions: frequent adverse reactions are those occurring in at least 1/100 patients; infrequent adverse reactions are those occurring in 1/100 to 1/1000 patients; rare reactions are those occurring in fewer than 1/1000 patients.

Body as a Whole - Frequent: chills; Infrequent: suicide attempt; Rare: acute abdominal syndrome, photosensitivity reaction.

Cardiovascular System - Frequent: palpitation; Infrequent: arrhythmia, hypotension1.

Digestive System - Infrequent: dysphagia, gastritis, gastroenteritis, melena, stomach ulcer; Rare: bloody diarrhea, duodenal ulcer, esophageal ulcer, gastrointestinal hemorrhage, hematemesis, hepatitis, peptic ulcer, stomach ulcer hemorrhage.

Hemic and Lymphatic System - Infrequent: ecchymosis; Rare: petechia, purpura.

Investigations - Frequent: QT interval prolongation (QTcF ≥450 msec)3.

Nervous System - Frequent: emotional lability; Infrequent: akathisia, ataxia, balance disorder1, bruxism1, buccoglossal syndrome, depersonalization, euphoria, hypertonia, libido increased, myoclonus, paranoid reaction; Rare: delusions.

Respiratory System - Rare: larynx edema.

Skin and Appendages - Infrequent: alopecia; Rare: purpuric rash.

Special Senses - Frequent: taste perversion; Infrequent: mydriasis.

Urogenital System - Frequent: micturition disorder; Infrequent: dysuria, gynecological bleeding2.

1 MedDRA dictionary term from integrated database of placebo controlled trials of 15870 patients, of which 9673 patients received fluoxetine.

2 Group term that includes individual MedDRA terms: cervix hemorrhage uterine, dysfunctional uterine bleeding, genital hemorrhage, menometrorrhagia, menorrhagia, metrorrhagia, polymenorrhea, postmenopausal hemorrhage, uterine hemorrhage, vaginal hemorrhage. Adjusted for gender.

3 QT prolongation data are based on routine ECG measurements in clinical trials.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of PROZAC. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or evaluate a causal relationship to drug exposure.

Voluntary reports of adverse reactions temporally associated with PROZAC that have been received since market introduction and that may have no causal relationship with the drug include the following: aplastic anemia, atrial fibrillation1, cataract, cerebrovascular accident1, cholestatic jaundice, dyskinesia (including, for example, a case of buccal-lingual-masticatory syndrome with involuntary tongue protrusion reported to develop in a 77-year-old female after 5 weeks of fluoxetine therapy and which completely resolved over the next few months following drug discontinuation), eosinophilic pneumonia1, epidermal necrolysis, erythema multiforme, erythema nodosum, exfoliative dermatitis, galactorrhea, gynecomastia, heart arrest1, hepatic failure/necrosis, hyperprolactinemia, hypoglycemia, immune-related hemolytic anemia, kidney failure, memory impairment, movement disorders developing in patients with risk factors including drugs associated with such reactions and worsening of pre-existing movement disorders, optic neuritis, pancreatitis1, pancytopenia, pulmonary embolism, pulmonary hypertension, QT prolongation, Stevens-Johnson syndrome, thrombocytopenia1, thrombocytopenic purpura, ventricular tachycardia (including Torsades de Pointes–type arrhythmias), vaginal bleeding, and violent behaviors1.

1 These terms represent serious adverse events, but do not meet the definition for adverse drug reactions. They are included here because of their seriousness.

DRUG INTERACTIONS

As with all drugs, the potential for interaction by a variety of mechanisms (e.g., pharmacodynamic, pharmacokinetic drug inhibition or enhancement, etc.) is a possibility.

Monoamine Oxidase Inhibitors (MAOI)

[See DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, and WARNINGS AND PRECAUTIONS].

CNS Acting Drugs

Caution is advised if the concomitant administration of PROZAC and such drugs is required. In evaluating individual cases, consideration should be given to using lower initial doses of the concomitantly administered drugs, using conservative titration schedules, and monitoring of clinical status [see CLINICAL PHARMACOLOGY].

Serotonergic Drugs

[See DOSAGE AND ADMINISTRATION, CONTRAINDICATIONS, and WARNINGS AND PRECAUTIONS].

Drugs That Interfere With Hemostasis (e.g., NSAIDS, Aspirin, Warfarin)

Serotonin release by platelets plays an important role in hemostasis. Epidemiological studies of the case-control and cohort design that have demonstrated an association between use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding have also shown that concurrent use of an NSAID or aspirin may potentiate this risk of bleeding. Altered anticoagulant effects, including increased bleeding, have been reported when SNRIs or SSRIs are coadministered with warfarin. Patients receiving warfarin therapy should be carefully monitored when fluoxetine is initiated or discontinued [see WARNINGS AND PRECAUTIONS].

Electroconvulsive Therapy (ECT)

There are no clinical studies establishing the benefit of the combined use of ECT and fluoxetine. There have been rare reports of prolonged seizures in patients on fluoxetine receiving ECT treatment.

Potential For Other Drugs To Affect PROZAC

Drugs Tightly Bound to Plasma Proteins — Because fluoxetine is tightly bound to plasma proteins, adverse effects may result from displacement of protein-bound fluoxetine by other tightly-bound drugs [see CLINICAL PHARMACOLOGY].

Potential For PROZAC To Affect Other Drugs

Pimozide

Concomitant use in patients taking pimozide is contraindicated. Pimozide can prolong the QT interval. Fluoxetine can increase the level of pimozide through inhibition of CYP2D6. Fluoxetine can also prolong the QT interval. Clinical studies of pimozide with other antidepressants demonstrate an increase in drug interaction or QT prolongation. While a specific study with pimozide and fluoxetine has not been conducted, the potential for drug interactions or QT prolongation warrants restricting the concurrent use of pimozide and PROZAC [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and Drugs That Prolong The QT Interval].

Thioridazine

Thioridazine should not be administered with PROZAC or within a minimum of 5 weeks after PROZAC has been discontinued, because of the risk of QT Prolongation [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and Drugs That Prolong The QT Interval].

In a study of 19 healthy male subjects, which included 6 slow and 13 rapid hydroxylators of debrisoquin, a single 25 mg oral dose of thioridazine produced a 2.4-fold higher Cmax and a 4.5-fold higher AUC for thioridazine in the slow hydroxylators compared with the rapid hydroxylators. The rate of debrisoquin hydroxylation is felt to depend on the level of CYP2D6 isozyme activity. Thus, this study suggests that drugs which inhibit CYP2D6, such as certain SSRIs, including fluoxetine, will produce elevated plasma levels of thioridazine.

Thioridazine administration produces a dose-related prolongation of the QT interval, which is associated with serious ventricular arrhythmias, such as Torsades de Pointes-type arrhythmias, and sudden death. This risk is expected to increase with fluoxetine-induced inhibition of thioridazine metabolism.

Drugs Metabolized By CYP2D6

Fluoxetine inhibits the activity of CYP2D6, and may make individuals with normal CYP2D6 metabolic activity resemble a poor metabolizer. Coadministration of fluoxetine with other drugs that are metabolized by CYP2D6, including certain antidepressants (e.g., TCAs), antipsychotics (e.g., phenothiazines and most atypicals), and antiarrhythmics (e.g., propafenone, flecainide, and others) should be approached with caution. Therapy with medications that are predominantly metabolized by the CYP2D6 system and that have a relatively narrow therapeutic index (see list below) should be initiated at the low end of the dose range if a patient is receiving fluoxetine concurrently or has taken it in the previous 5 weeks. Thus, his/her dosing requirements resemble those of poor metabolizers. If fluoxetine is added to the treatment regimen of a patient already receiving a drug metabolized by CYP2D6, the need for decreased dose of the original medication should be considered. Drugs with a narrow therapeutic index represent the greatest concern (e.g., flecainide, propafenone, vinblastine, and TCAs). Due to the risk of serious ventricular arrhythmias and sudden death potentially associated with elevated plasma levels of thioridazine, thioridazine should not be administered with fluoxetine or within a minimum of 5 weeks after fluoxetine has been discontinued [see CONTRAINDICATIONS].

Tricyclic Antidepressants (TCAs)

In 2 studies, previously stable plasma levels of imipramine and desipramine have increased greater than 2- to 10-fold when fluoxetine has been administered in combination. This influence may persist for 3 weeks or longer after fluoxetine is discontinued. Thus, the dose of TCAs may need to be reduced and plasma TCA concentrations may need to be monitored temporarily when fluoxetine is coadministered or has been recently discontinued [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Benzodiazepines

The half-life of concurrently administered diazepam may be prolonged in some patients [see CLINICAL PHARMACOLOGY]. Coadministration of alprazolam and fluoxetine has resulted in increased alprazolam plasma concentrations and in further psychomotor performance decrement due to increased alprazolam levels.

Antipsychotics

Some clinical data suggests a possible pharmacodynamic and/or pharmacokinetic interaction between SSRIs and antipsychotics. Elevation of blood levels of haloperidol and clozapine has been observed in patients receiving concomitant fluoxetine.

Anticonvulsants

Patients on stable doses of phenytoin and carbamazepine have developed elevated plasma anticonvulsant concentrations and clinical anticonvulsant toxicity following initiation of concomitant fluoxetine treatment.

Lithium

There have been reports of both increased and decreased lithium levels when lithium was used concomitantly with fluoxetine. Cases of lithium toxicity and increased serotonergic effects have been reported. Lithium levels should be monitored when these drugs are administered concomitantly [see WARNINGS AND PRECAUTIONS].

Drugs Tightly Bound To Plasma Proteins

Because fluoxetine is tightly bound to plasma proteins, the administration of fluoxetine to a patient taking another drug that is tightly bound to protein (e.g., Coumadin, digitoxin) may cause a shift in plasma concentrations potentially resulting in an adverse effect [see CLINICAL PHARMACOLOGY].

Drugs Metabolized by CYP3A4

In an in vivo interaction study involving coadministration of fluoxetine with single doses of terfenadine (a CYP3A4 substrate), no increase in plasma terfenadine concentrations occurred with concomitant fluoxetine.

Additionally, in vitro studies have shown ketoconazole, a potent inhibitor of CYP3A4 activity, to be at least 100 times more potent than fluoxetine or norfluoxetine as an inhibitor of the metabolism of several substrates for this enzyme, including astemizole, cisapride, and midazolam. These data indicate that fluoxetine’s extent of inhibition of CYP3A4 activity is not likely to be of clinical significance.

Olanzapine

Fluoxetine (60 mg single dose or 60 mg daily dose for 8 days) causes a small (mean 16%) increase in the maximum concentration of olanzapine and a small (mean 16%) decrease in olanzapine clearance. The magnitude of the impact of this factor is small in comparison to the overall variability between individuals, and therefore dose modification is not routinely recommended.

When using PROZAC and olanzapine and in combination, also refer to the Drug Interactions section of the package insert for Symbyax.

Drugs That Prolong The QT Interval

Do not use PROZAC in combination with thioridazine or pimozide. Use PROZAC with caution in combination with other drugs that cause QT prolongation. These include: specific antipsychotics (e.g., ziprasidone, iloperidone, chlorpromazine, mesoridazine, droperidol); specific antibiotics (e.g., erythromycin, gatifloxacin, moxifloxacin, sparfloxacin); Class 1A antiarrhythmic medications (e.g., quinidine, procainamide); Class III antiarrhythmics (e.g., amiodarone, sotalol); and others (e.g., pentamidine, levomethadyl acetate, methadone, halofantrine, mefloquine, dolasetron mesylate, probucol or tacrolimus). PROZAC is primarily metabolized by CYP2D6. Concomitant treatment with CYP2D6 inhibitors can increase the concentration of PROZAC. Concomitant use of other highly protein-bound drugs can increase the concentration of PROZAC [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS, Potential For PROZAC To Affect Other Drugs and CLINICAL PHARMACOLOGY].

Drug Abuse And Dependence

Dependence

PROZAC has not been systematically studied, in animals or humans, for its potential for abuse, tolerance, or physical dependence. While the premarketing clinical experience with PROZAC did not reveal any tendency for a withdrawal syndrome or any drug seeking behavior, these observations were not systematic and it is not possible to predict on the basis of this limited experience the extent to which a CNS active drug will be misused, diverted, and/or abused once marketed. Consequently, healthcare providers should carefully evaluate patients for history of drug abuse and follow such patients closely, observing them for signs of misuse or abuse of PROZAC (e.g., development of tolerance, incrementation of dose, drug-seeking behavior).

Read the entire FDA prescribing information for Prozac (Fluoxetine Hcl)

© Prozac Patient Information is supplied by Cerner Multum, Inc. and Prozac Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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