fluoxetine hydrochloride

(floo ox' e teen)

Apo-Fluoxetine (CAN), Novo-Fluoxetine (CAN), PMS-Fluoxetine (CAN), Prozac, Prozac Weekly, Sarafem

Pregnancy Category C

Drug classes

Antidepressant

SSRI

Therapeutic actions

Acts as an antidepressant by inhibiting CNS neuronal uptake of serotonin; blocks uptake of serotonin with little effect on norepinephrine; little affinity for muscarinic, histaminergic, and alpha₁-adrenergic receptors.

Indications

· Treatment of depression; most effective in patients with major depressive disorder

· Treatment of obsessive-compulsive disorder

· Treatment of bulimia

· Sarafem: Treatment of premenstrual dysphoric disorder (PMDD)

· Prozac: Treatment of panic disorder with or without agoraphobia

· Unlabeled use: Treatment of obesity, alcoholism, numerous psychiatric disorders, chronic pain, various neuropathies

Contraindications and cautions

· Contraindicated with hypersensitivity to fluoxetine, pregnancy.

· Use cautiously with impaired hepatic or renal function, diabetes mellitus, lactation, seizures, history of suicide attempts.

Available forms

Tablets—10, 20 mg; capsules—10, 20, 40 mg; liquid—20 mg/5 mL; DR capsules—90 mg

Dosages

ADULTS

· Antidepressant: The full antidepressant effect may not be seen for up to 4–6 wk. Initially, 20 mg/day PO in the morning. If no clinical improvement is seen, increase dose after several weeks. Administer doses > 20 mg/day on a bid schedule. Do not exceed 80 mg/day. Once stabilized, may switch to 90-mg DR capsules once a week.

· Obsessive-compulsive disorder: Initially, 20 mg/day PO. If no clinical improvement is seen, increase dose after several weeks. Usual dosage range, 20–60 mg/day; may require up to 5 wk for effectiveness. Do not exceed 80 mg/day.

· Bulimia: 60 mg/day PO in the morning.

· PMDD (Sarafem): 20 mg/day PO or 20 mg/day PO starting 14 days prior to the anticipated beginning of menses and continuing through the first full day of menses, then no drug until 14 days before next menses; do not exceed 80 mg/day.

· Panic disorder (Prozac): 10 mg/day PO for the first week, increase to 20 mg/day if needed. Maximum dose, 60 mg/day.

PEDIATRIC PATIENTS

< 7 yr: Safety and efficacy not established.

7–17 yr:

· Obsessive-compulsive disorder: Initially, 10 mg/day PO. After 2 wk increase to 20–60 mg/day. Suggested range, 20–60 mg/day PO.

8–18 yr:

· Major depressive order: 10 mg/day PO; may be increased to 20 mg/day after several weeks.

GERIATRIC PATIENTS OR PATIENTS WITH HEPATIC OR RENAL IMPAIRMENT

Give a lower or less frequent dose. Monitor response to guide dosage.

Pharmacokinetics

Route	Onset	Peak
Oral	Slow	6–8 hr

Metabolism: Hepatic; T_1/2: 2–9 days

Distribution: Crosses placenta; enters breast milk

Excretion: Urine and feces

Adverse effects

· CNS: Headache, nervousness, insomnia, drowsiness, anxiety, tremor, dizziness, light-headedness, agitation, sedation, abnormal gait, seizures

· CV: Hot flashes, palpitations

· Dermatologic: Sweating, rash, pruritus, acne, alopecia, contact dermatitis

· GI: Nausea, vomiting, diarrhea, dry mouth, anorexia, dyspepsia, constipation, taste changes, flatulence, gastroenteritis, dysphagia, gingivitis

· GU: Painful menstruation, sexual dysfunction, frequency, cystitis, impotence, urgency, vaginitis

· Respiratory: URIs, pharyngitis, cough, dyspnea, bronchitis, rhinitis

· Other: Weight loss, asthenia, fever

Interactions

Drug-drug

· Increased therapeutic and toxic effects of TCAs

· Do not use with thioridazine (increased levels of thioridazine)

· Decreased effectiveness if taken while smoking

· Increased toxicity of lithium; avoid this combination

· WARNING: Possible fatal reactions with MAOIs; do not administer together; 2-wk washout period needed

· Additive CNS effects if combined with benzodiazepines, alcohol; avoid these combinations

· Avoid administration with other serotonergic drugs; may lead to serotonin syndrome

Drug-alternative therapy

· Increased risk of severe reaction if combined with St. John's wort therapy.

Nursing considerations

CLINICAL ALERT!

Name confusion has been reported between Sarafem (fluoxetine) and Serophene (clomiphene); use caution.

Assessment

· History: Hypersensitivity to fluoxetine, impaired hepatic or renal function, diabetes mellitus, lactation, pregnancy, seizures

· Physical: Weight, T; skin rash, lesions; reflexes, affect; bowel sounds, liver evaluation; P, peripheral perfusion; urinary output, renal and liver function tests, CBC

Interventions

· Arrange for lower or less frequent doses in elderly patients and patients with hepatic or renal impairment.

· WARNING: Establish suicide precautions for severely depressed patients. Limit quantity of capsules dispensed.

· Administer drug in the morning. If dose of > 20 mg/day is needed, administer in divided doses.

· Monitor patient for response to therapy for up to 4 wk before increasing dose.

· Switch to once a week therapy by starting weekly dose 7 days after last 20 mg/day dose. If response is not satisfactory, reconsider daily dosing.

Teaching points

· It may take up to 4–6 wk before the full effect occurs. Take in the morning (or in divided doses if necessary). If you are taking the once weekly capsule, mark calendar with reminders of drug day.

· Do not take this drug during pregnancy. If you think that you are pregnant or wish to become pregnant, consult with your physician.

· You may experience these side effects: Dizziness, drowsiness, nervousness, insomnia (avoid driving or performing hazardous tasks); nausea, vomiting, weight loss (eat frequent small meals; monitor your weight loss); sexual dysfunction; flulike symptoms.

· Report rash, mania, seizures, severe weight loss.

· Keep this drug, and all medications, out of the reach of children.

Adverse effects in Italic are most common; those in Bold are life-threatening.