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Pharmacologic class: Selective serotonin reuptake inhibitor
Therapeutic class: Antidepressant
Pregnancy risk category B
Selectively inhibits serotonin reuptake in CNS; has little to no effect on norepinephrine and dopamine reuptake
Capsules: 10 mg, 15 mg, 20 mg, 40 mg
Capsules (delayed-release): 90 mg
Oral solution: 20 mg/5 ml
Tablets: 10 mg, 15 mg, 20 mg
Indications and dosages
➣ Major depressive disorder (MDD)
Adults: 20 mg/day P.O. in morning. After several weeks, may increase by 20 mg/day at weekly intervals. Give dosages above 20 mg/day in two divided doses (morning and noon); don't exceed 80 mg/day. Patients stabilized on 20 mg/day may be switched to 90-mg/week delayed-release capsules (Prozac Weekly) 7 days after last 20-mg dose.
Children ages 8 to 18: Initially, 10 to 20 mg/day P.O. After 1 week at 10 mg daily, dosage should be increased to 20 mg/day. However, because of higher plasma levels in lower-weight children, starting and target dose in this group may be 10 mg/day. Dosage increase to 20 mg/day may be considered after several weeks if insufficient clinical improvement occurs.
➣ Obsessive-compulsive disorder (OCD)
Adults: Initially, 20 mg/day P.O. in morning. After several weeks, may increase dosage. Give doses above 20 mg/day once daily (morning) or in two divided doses b.i.d. (morning and noon). Dosage range of 20 to 60 mg/day is recommended; however, dosages of up to 80 mg/day have been well tolerated. Don't exceed 80 mg/day.
Children ages 7 to 17: Initially, 10 mg/day P.O. in morning in adolescents and higher-weight children; after 2 weeks, may increase dosage to 20 mg/day. Additional dosage increases may be considered after several more weeks if insufficient clinical improvement occurs. Dosage range of 20 to 60 mg/day is recommended. Initially, 10 mg/day P.O. in lower-weight children; may increase dosage after several more weeks if insufficient clinical improvement occurs. Dosage range of 20 to 30 mg/day is recommended. Experience with daily doses greater than 20 mg is very minimal; there is no experience with doses greater than 60 mg.
➣ Acute treatment of depressive episodes associated with bipolar I disorder
Adults: Initially, 20 mg fluoxetine P.O. with 5 mg olanzapine P.O. daily; dosage range of fluoxetine is 20 to 50 mg; olanzapine, 5 to 12.5 mg. Safety of fluoxetine doses above 75 mg and olanzapine doses above 18 mg haven't been established
➣ Bulimia nervosa
Adults: 60 mg/day P.O.; may be titrated upward over several days
➣ Panic disorder
Adults: 10 mg/day P.O. for 1 week; then, if needed, increase to 20 mg/day. Dosage increases of up to 60 mg/day may be considered after several weeks if patient doesn't respond to lower dosage.
➣ Premenstrual dysphoric disorder
Adults: 20 mg/day (Sarafem) P.O., not to exceed 80 mg/day
• Hepatic impairment
• Concurrent disease or multiple concomitant medications
• Pregnant women during third trimester
• Elderly patients
• Diabetic peripheral neuropathy
• Bipolar II disorder
• Borderline personality disorder
• Posttraumatic stress disorder
• Social phobia
• Hypersensitivity to drug
• MAO inhibitor use within past 14 days
• Concurrent use of thioridazine or within 5 weeks of discontinuing fluoxetine
• Concurrent use of pimozide
Use cautiously in:
• hepatic or renal impairment, diabetes mellitus, cardiovascular disease, concomitant illness, acute narrow-angle glaucoma
• history of seizures, serotonin syndrome or neuroleptic malignant syndrome, clinical worsening and suicidal thinking and behavior, activation of mania or hypomania
• hyponatremia in association with syndrome of inappropriate antidiuretic hormone secretion
• concurrent use of NSAIDs, aspirin, warfarin, or other drugs that affect coagulation
• concurrent use of tryptophan (use not recommended)
• pregnant patients (third trimester)
• breastfeeding patients (use not recommended)
• children younger than age 7 (in OCD use), younger than age 8 (in MDD use), younger than age 18 for all other uses (safety and efficacy not established).
☞ Be aware that drug should be discontinued 5 weeks before MAO inhibitor or thioridazine therapy begins.
• Give before 2 P.M. to prevent nighttime insomnia.
• Be aware that drug should be gradually reduced rather than abruptly stopped whenever possible.
CNS: anxiety, drowsiness, headache, insomnia, abnormal dreams, dizziness, fatigue, nervousness, hypomania, mania, weakness, tremor, seizures, suicidal ideation
CV: chest pain, palpitations, prolonged QTc interval
EENT: visual disturbances, stuffy nose, sinusitis, pharyngitis
GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, dry mouth, anorexia
GU: urinary frequency, sexual dysfunction, dysmenorrhea
Metabolic: hypouricemia, hypocalcemia, hyponatremia, hyperglycemia, hypoglycemia
Musculoskeletal: joint, back, or muscle pain
Respiratory: cough, upper respiratory tract infection, dyspnea, respiratory distress
Skin: diaphoresis, pruritus, erythema nodosum, flushing, rash
Other: abnormal taste, weight loss, fever, flulike symptoms, hot flashes, serotonin syndrome, neuroleptic malignant syndrome (NMS), allergic reactions, hypersensitivity reactions
Drug-drug. Adrenergics: increased sensitivity to adrenergics, increased risk of serotonin syndrome
Alprazolam: decreased metabolism and increased effects of alprazolam
Antihistamines, opioids, other antidepressants, sedative-hypnotics: additive CNS depression
Aspirin, NSAIDs, warfarin, other drugs that affect coagulation: increased risk of GI or other bleeding
Buspirone: potentiation of fluoxetine effects, increased risk of seizures
Carbamazepine, clozapine, digoxin, haloperidol, lithium, phenytoin, warfarin: increased blood levels of these drugs, greater risk of adverse reactions
CYP450-2D6 inducers: increased effects of these drugs
Cyproheptadine: decrease in or reversal of fluoxetine effects
Digoxin, warfarin, other highly protein-bound drugs: increased risk of adverse reactions to either drug
Efavirenz, ritonavir, saquinavir, other CYP450 inhibitors: serotonergics, triptans: increased risk of serotonin syndrome
MAO inhibitors: confusion, agitation, seizures, hypertension, and hyperpyrexia (serotonin syndrome)
Pimozide: increased risk of drug interaction or QTc-interval prolongation
Thioridazine: increased risk of QTc-interval prolongation or potential for elevated thioridazine plasma level
Other antidepressants, phenothiazines, risperidone, tryptophan: increased risk of adverse reactions
Ritonavir: increased ritonavir blood level
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, blood urea nitrogen, creatine kinase, electrolytes, glucose: increased levels
Sodium: decreased level
Drug-herbs. St. John's wort: increased risk of serotonin syndrome
Drug-behaviors. Alcohol use: additive CNS depression
☞ Monitor patient for signs and symptoms of depression. Assess for suicidal ideation.
☞ Evaluate neurologic status, watching especially for seizures.
☞ Monitor cardiovascular status, particularly for prolonged QTc interval.
• Assess weight regularly. Watch for signs of eating disorders.
☞ Monitor patient for signs and symptoms of allergic reactions, serotonin syndrome, or NMS-like reactions. Discontinue drug immediately and initiate supportive treatment if these reactions occur.
• Encourage patient to establish effective bedtime routine to minimize sleep disorders.
• Tell patient drug may take 4 weeks or longer to be fully effective.
☞ Instruct patient to contact prescriber if he develops worsening depression or has suicidal thoughts.
☞ Instruct patient to immediately stop drug and report signs and symptoms of allergic reactions (rash), serotonin syndrome, or neuroleptic malignant syndrome-like reactions.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Tell female patient to inform prescriber if she is pregnant or breastfeeding.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.
PROzac Weekly(trade name),
Pharmacologic: selective serotonin reuptake inhibitors ssris
- Diabetic neuropathy,
- Raynaud’s phenomenon,
- Social anxiety disorder (social phobia),
- Posttraumatic stress disorder (PTSD).
- panic disorder,
Time/action profile (antidepressant effect)
|PO||1–4 wk||unknown||2 wk|
Adverse Reactions/Side Effects
Central nervous system
- neuroleptic malignant syndrome (life-threatening)
- seizures (life-threatening)
- suicidal thoughts (life-threatening)
- anxiety (most frequent)
- drowsiness (most frequent)
- headache (most frequent)
- insomnia (most frequent)
- nervousness (most frequent)
- abnormal dreams
Ear, Eye, Nose, Throat
- stuffy nose
- visual disturbances
- torsades de pointes (life-threatening)
- chest pain
- QT interval prolongation
- diarrhea (most frequent)
- abdominal pain
- abnormal taste
- dry mouth
- weight loss
- sexual dysfunction (most frequent)
- urinary frequency
- ↑ sweating (most frequent)
- pruritus (most frequent)
- erythema nodusum
Fluid and Electrolyte
- back pain
- tremor (most frequent)
- serotonin syndrome (life-threatening)
- allergic reactions
- flu-like syndrome
- hot flashes
- sensitivity reaction
Drug-Drug interactionDiscontinue use of MAO inhibitors for 14 days before fluoxetine therapy; combined therapy may result in confusion, agitation, seizures, hypertension, and hyperpyrexia (serotonin syndrome). Fluoxetine should be discontinued for at least 5 wk before MAO inhibitor therapy is initiated.Concurrent use with MAO-inhibitor-like drugs, such as linezolid or methylene blue may ↑ risk of serotonin syndrome; concurrent use contraindicated; do not start therapy in patients receiving linezolid or methylene blue ; if linezolid or methylene blue need to be started in a patient receiving fluoxetine, immediately discontinue fluoxetine and monitor for signs/symptoms of serotonin syndrome for 2 wk or until 24 hr after last dose of linezolid or methylene blue, whichever comes first (may resume fluoxetine therapy 24 hr after last dose of linezolid or methylene blue)Concurrent use with pimozide may ↑ risk of QT interval prolongation.↑ levels of thioridazine may ↑ risk of QT interval prolongation (concurrent use contraindicated; fluoxetine should be discontinued for at least 5 wk before thioridazine is initiated).QT interval prolonging drugs may ↑ the risk of QT interval prolongation with arrhythmias; avoid concurrent useInhibits the activity of cytochrome P450 2D6 enzyme in the liver and ↑ effects of drugs metabolized by this enzyme system.Medications that inhibit the P450 enzyme system (including ritonavir, saquinavir, and efavirenz ) may ↑ risk of developing the serotonin syndrome). For concurrent use with ritonavir ↓ fluoxetine dose by 70%; if initiating fluoxetine, start with 10 mg/day dose.↓ metabolism and ↑ effects of alprazolam (decrease alprazolam dose by 50%).Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SNRIs, fentanyl, buspirone, tramadol, and triptans ↑ risk of serotonin syndrome↑ CNS depression with alcohol, antihistamines, other antidepressants, opioid analgesics, or sedative/hypnotics.↑ risk of side effects and adverse reactions with other antidepressants, risperidone, or phenothiazines.May ↑ effectiveness/risk of toxicity from carbamazepine, clozapine, digoxin, haloperidol, phenytoin, lithium, or warfarin.May ↓ the effects of buspirone.Cyproheptadine may ↓ or reverse effects of fluoxetine.May ↑ sensitivity to adrenergics and increase the risk of serotonin syndrome.May alter the activity of other drugs that are highly bound to plasma proteins.↑ risk of serotonin syndrome with 5HT1 agonists.↑ risk of bleeding with NSAIDS, aspirin, clopidogrel, or warfarin.↑ risk of serotonin syndrome with St. John’s wort and SAMe.
Availability (generic available)
- Monitor mood changes. Inform health care professional if patient demonstrates significant increase in anxiety, nervousness, or insomnia.
- Assess for suicidal tendencies, especially during early therapy. Restrict amount of drug available to patient. Risk may be increased in children, adolescents, and adults ≤24 yr. After starting therapy, children, adolescents, and young adults should be seen by health care professional at least weekly for 4 wk, every 3 wk for next 4 wk, and on advice of health care professional thereafter.
- Monitor appetite and nutritional intake. Weigh weekly. Notify health care professional of continued weight loss. Adjust diet as tolerated to support nutritional status.
- Assess for sensitivity reaction (urticaria, fever, arthralgia, edema, carpal tunnel syndrome, rash, hives, lymphadenopathy, respiratory distress) and notify health care professional if present; symptoms usually resolve by stopping fluoxetine but may require administration of antihistamines or corticosteroids.
- Assess for sexual side effects (erectile dysfunction; decreased libido).
- Monitor for development of neuroleptic malignant syndrome (fever, respiratory distress, tachycardia, seizures, diaphoresis, arrhythmias, hypertension or hypotension, pallor, tiredness, severe muscle stiffness, loss of bladder control). Report immediately.
- Assess for serotonin syndrome (mental changes [agitation, hallucinations, coma], autonomic instability [tachycardia, labile BP, hyperthermia], neuromuscular aberrations [hyperreflexia, incoordination], and/or GI symptoms [nausea, vomiting, diarrhea]), especially in patients taking other serotonergic drugs (SSRIs, SNRIs, triptans).
- OCD: Assess for frequency of obsessive-compulsive behaviors. Note degree to which these thoughts and behaviors interfere with daily functioning.
- Bulimia Nervosa: Assess frequency of binge eating and vomiting during therapy.
- PMDD: Monitor mood prior to and periodically during therapy.
- Lab Test Considerations: Monitor CBC and differential periodically during therapy. Notify health care professional if leukopenia, anemia, thrombocytopenia, or increased bleeding time occurs.
- Proteinuria and mild ↑ in AST may occur during sensitivity reactions.
- May cause ↑ in serum alkaline phosphatase, ALT, BUN, creatine phosphokinase, hypouricemia, hypocalcemia, hypoglycemia or hyperglycemia, and hyponatremia.
- May cause hypoglycemia in patient with diabetes.
Potential Nursing DiagnosesIneffective coping (Indications)
Risk for injury (Side Effects)
Sexual dysfunction (Side Effects)
- Do not confuse fluoxetine with duloxetine, paroxetine, or Loxitane (loxapine). Do not confuse Prozac with Prilosec (omeprazole), Prograf (tacrolimus), or Provera (medroxyprogesterone). Do not confuse Sarafem (fluoxetine) with Serophene (clomiphene).
- Oral: Administer as a single dose in the morning. Some patients may require increased amounts, in divided doses, with a 2nd dose at noon.
- May be administered with food to minimize GI irritation. Do not open, dissolve, chew, or crush delayed-release capsules.
- Instruct patient to take fluoxetine as directed. Take missed doses as soon as remembered unless almost time for next dose, then omit and return to regular schedule. Do not double doses or discontinue without consulting health care professional; discontinuation may cause anxiety, insomnia, nervousness.
- May cause drowsiness, dizziness, impaired judgment, and blurred vision. Caution patient to avoid driving and other activities requiring alertness until response to the drug is known.
- Advise patient, family, and caregivers to look for suicidality, especially during early therapy or dose changes. Notify health care professional immediately if thoughts about suicide or dying, attempts to commit suicide, new or worse depression or anxiety, agitation or restlessness, panic attacks, insomnia, new or worse irritability, aggressiveness, acting on dangerous impulses, mania, or other changes in mood or behavior or if symptoms of serotonin syndrome occur.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications. Advise patient to avoid taking other CNS depressants or alcohol.
- Caution patient to change positions slowly to minimize dizziness.
- Inform patient that frequent mouth rinses, good oral hygiene, and sugarless gum or candy may minimize dry mouth. If dry mouth persists for more than 2 wk, consult health care professional regarding use of saliva substitute.
- Caution patient to wear protective clothing and use sunscreen to prevent photosensitivity reactions.
- Inform patient that medication may cause decreased libido.
- Advise patient to notify health care professional if symptoms of sensitivity reaction occur or if headache, nausea, anorexia, anxiety, or insomnia persists.
- Instruct female patients to inform health care professional if pregnancy is planned or suspected, or if breast feeding.
- Emphasize the importance of follow-up exams to monitor progress.
- Increased sense of well-being.
- Renewed interest in surroundings. May require 1–4 wk of therapy to obtain antidepressant effects.
- Decrease in obsessive-compulsive behaviors.
- Decrease in binge eating and vomiting in patients with bulimia nervosa.
- Decreased incidence frequency of panic attacks.
- Decreased mood alterations associated with PMDD.