FLUOXETINE HYDROCHLORIDE

(flu'ox-e-tine)

Prozac, Prozac Weekly, Sarafem
Classifications: psychotherapeutic agent; selective serotonin reuptake inhibitor (ssri); antidepressant;
Therapeutic: antidepressant; ssri
Pregnancy Category: C

Availability

10 mg tablets; 10 mg, 20 mg capsules; 20 mg/5 mL solution; 90 mg sustained release capsules (Prozac Weekly)

Action

A selective serotonin reuptake inhibitor (SSRI). Antidepressant effect is presumed to be linked to its inhibition of CNS neuronal uptake of serotonin, a neurotransmitter.

Therapeutic Effect

Effectiveness may take from several days to 5 wk to develop fully. Drug has antidepressant, antiobsessive-compulsive, and antibulimic actions.

Uses

Depression, geriatric depression, obsessive-compulsive disorder (OCD), bulimia nervosa, premenstrual dysphoric disorder.

Unlabeled Uses

Obesity.

Contraindications

Hypersensitivity to fluoxetine or other SSRI drugs; concurrent administration with MAOIs, or thioridazine; pregnancy (category C), children <7 y for OCD, children <8 y for depression; suicidal ideation.

Cautious Use

Hepatic and renal impairment, renal failure, abrupt discontinuation, anorexia nervosa, mania, bleeding; hyponatremia, cardiac disease, dehydration, diabetes mellitus, patients with history of suicidal ideations; seizure disorders, ECT, hepatic disease. Older adults may require dose adjustments; lactation.

Route & Dosage

Depression, Obsessive-Compulsive Disorder
Adult: PO 20 mg/d in a.m., may increase by 20 mg/d at weekly intervals (max: 80 mg/d); 20 mg/d in a.m.; when stable may switch to 90 mg sustained release capsule qwk (max: 90 mg/wk)
Child (>7 y): PO 10–20 mg/d in a.m. (max: 60 mg/d for OCD)
Geriatric: PO Start with 10 mg/d

Premenstrual Dysphoric Disorder
Adult: PO 10–20 mg q.d. (max: 60 mg/d)

Bulimia Nervosa
Adult: PO 60 mg q.d.

Administration

Oral

Give as a single dose in morning. Give in two divided doses; one in a.m. and one at noon to prevent insomnia, when more than 20 mg/d prescribed.
Provide suicidal or potentially suicidal patient with small quantities of prescription medication.
Monitor for worsening of depression or expression of suicidal ideations.
Store at 15°–25° C (59°–77° F).

Adverse Effects (≥1%)

CNS: Headache, nervousness, anxiety, insomnia, drowsiness, fatigue, tremor, dizziness. CV: Palpitations, hot flushes, chest pain. GI: Nausea, diarrhea, anorexia, dyspepsia, increased appetite, dry mouth. Skin: Rash, pruritus, sweating, hypersensitivity reactions. Special Senses: Blurred vision. Body as a Whole: Myalgias, arthralgias, flu-like syndrome, hyponatremia. Urogenital: Sexual dysfunction, menstrual irregularities.

Interactions

Drug: Concurrent use of tryptophan may cause agitation, restlessness, and GI distress; mao inhibitors, selegiline may increase risk of severe hypertensive reaction and death; increases half-life of diazepam; may increase toxicity of tricyclic antidepressants; amphetamines, cilostazol, nefazodone, pentazocine, propafenone, sibutramine, tramadol, venlafaxine may increase risk of serotonin syndrome; may inhibit metabolism of carbamazepine, phenytoin, ritonavir; increased ergotamine toxicity with dihydroergotamine, ergotamine. antipsychotics like pimozide can cause QT prolongation. Herbal: St. John's wort may cause serotonin syndrome.

Pharmacokinetics

Absorption: 60–80% from GI tract. Onset: 1–3 wk. Peak: 4–8 h. Distribution: Widely distributed, including CNS. Metabolism: In liver to active metabolite, norfluoxetine. Elimination: >80% in urine; 12% in feces. Half-Life: Fluoxetine 2–3 d, norfluoxetine 7–9 d.

Nursing Implications

Assessment & Drug Effects

Monitor children and adolescents for changes in behavior and suicidal ideation.
Use with caution in the older adult patient or patient with impaired renal or hepatic function (may need lower dose).
Use with caution in anorexic patient, since weight loss is a possible side effect.
Monitor for S&S of anaphylactoid reaction (see Appendix F).
Lab tests: Periodic serum electrolytes; monitor closely plasma glucose in diabetes.
Monitor serum sodium level for development of hyponatremia, especially in patients who are taking diuretics or are otherwise hypovolemic.
Monitor diabetics for loss of glycemic control; hypoglycemia has occurred during initiation of therapy, and hyperglycemia during drug withdrawal.
Monitor for S&S of improved affect. Requires approximately 2–3 wk for therapeutic effects to be felt.
Weigh weekly to monitor weight loss, particularly in the older adult or nutritionally compromised patient. Report significant weight loss to physician.
Observe for and promptly report rash or urticaria and S&S of fever, leukocytosis, arthralgias, carpal tunnel syndrome, edema, respiratory distress, and proteinuria. Drug may have to be discontinued or adjunctive therapy instituted with steroids or antihistamines.
Observe for dizziness and drowsiness and employ safety measures (up with assistance, side rails, etc.) as indicated.
Monitor for and report increased anxiety, nervousness, or insomnia; may need modification of drug dose.
Monitor for seizures in patients with a history of seizures. Use appropriate safety precautions.
Supervise patients closely who are high suicide risks; especially during initial therapy.
Monitor patients with hepatic or renal impairment carefully for S&S of toxicity (e.g., agitation, restlessness, nausea, vomiting, seizures).

Patient & Family Education

Notify physician of intent to become pregnant.
Notify physician of any rash; possible sign of a serious group of adverse effects.
Do not drive or engage in potentially hazardous activities until response to drug is known; especially if dizziness noted.
Monitor blood glucose for loss of glycemic control if diabetic.
Note: Drug may increase seizure activity in those with history of seizure.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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