Fluoxetine HCl

A to Z Drug Facts

 Action Blocks reuptake of serotonin, enhancing serotonergic function.

 Indications

Prozac: Depression; obsessive-compulsive disorder (OCD); bulimia nervosa.

Sarafem: Premenstrual dysphoric disorder (PMDD). Unlabeled use(s): Alcoholism; anorexia nervosa; attention deficit hyperactivity disorder; bipolar II disorder; borderline personality disorder; chronic rheumatoid pain; diabetic peripheral neuropathy; kleptomania; levodopa-induced dyskinesia; migraine, chronic daily headaches, and tension-type headache; narcolepsy; panic disorder; schizophrenia; social phobia; trichotillomania.

 Contraindications Concurrent use with, or within 14 days of discontinuation of, MAOIs.

 Route/Dosage

Prozac

Depression

ADULTS: PO 20 to 80 mg/day. Weekly dosing (90 mg delayed-release capsule) may be started 7 days after last 20 mg/day dose. If response is not satsifactory, consider re-establishing daily dosage regimen.

OCD

ADULTS: PO 20 to 80 mg/day.

Bulimia Nervosa

PO 60 mg/day administered in morning.

Sarafem

PMDD:

ADULTS: PO 20 mg/day every day of menstrual cycle or daily starting 14 days prior to anticipated onset of menstruation through the first full day of menses and repeating for each new cycle (max dose, 80 mg/day).

 Interactions

5-HT₁ agonists (eg, naratriptan, rizatriptan, sumatriptan, zolmitriptan): Weakness, hyperreflexia, and incoordination have been reported rarely. Benzodiazepines: Coadministration of alprazolam and fluoxetine has resulted in increased alprazolam levels and decreased psychomotor performance. Halve the initial alprazolam dose and titrate to lowest effective dose. Beta Blockers: Excessive beta blockade (bradycardia) may occur with certain beta blockers (eg, carvedilol, metoprolol, propranolol). Buspirone: Effects of buspirone may be decreased. Carbamazepine: Increased carbamazepine levels, causing toxicity. Clozapine: Elevated serum clozapine levels have occurred. Closely monitor patients on concomitant administration. Cyclosporine: Concentrations of cyclosporine may be elevated, increasing the risk of toxicity. Cyproheptadine: Decreased or reversed effects of fluoxetine. Haloperidol: Serum concentrations of haloperidol may be increased; recall memory and attentional function tests may be delayed. Hydantoins (eg, phenytoin): Increased hydantoin levels, causing toxicity. Lithium: Lithium levels may be increased or decreased by fluoxetine with possible neurotoxicity and increased serotonergic effects. MAOIs: Combination may lead to serious, possibly fatal, reactions. Discontinue MAOI at least 14 days before starting fluoxetine; discontinue fluoxetine at least 5 wk before starting MAOI. Sympathomimetics (eg, amphetamine): Sensitivity of sympathomimetics and risk of “serotonin syndrome” may be increased. Tricyclic antidepressants: Increased toxic effects of tricyclic antidepressant.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Hot flashes; palpitations; angina; heart block; cerebral ischemia; MI; ventricular arrhythmias. CNS: Agitation; anxiety; nervousness; headache; insomnia; abnormal dreams; drowsiness; dizziness; tremor; fatigue; decreased libido; decreased concentration; seizures; delusions; hallucinations; coma. DERM: Increased sweating; rash; itching; erythema multiforme. EENT: Visual disturbances. GI: Nausea; vomiting; diarrhea; dry mouth; anorexia; upset stomach; constipation; abdominal pain; change in taste. GU: Painful menstruation; sexual dysfunction (decreased libido); frequent micturition; urinary tract infection. HEMA: Blood dyscrasias; leukopenia; petechiae; purpura; altered platelet function. META: Weight loss; hypoglycemia; hyponatremia. RESP: Flu-like symptoms; bronchitis; rhinitis; yawning; coughing; asthma; pneumonia; apnea; lung edema; pleural effusion. OTHER: Weakness; chills; joint or muscle pain; fever; hypersensitivity reaction.

 Precautions

Pregnancy: Category C. Lactation: Excreted in breast milk. Children: Safety and efficacy not established. Anorexia: Weight loss and decreased appetite are more likely to occur with fluoxetine than with tricyclic antidepressants. Diabetes mellitus: May alter glycemic control. Insulin dosing may need adjustment. Dose changes: The long elimination half-life of fluoxetine means that changes in dose will not be fully reflected in plasma for several weeks, affecting titration to final dose and withdrawal from treatment. Mania/Hypomania: Fluoxetine may precipitate mania/hypomania in susceptible patients. Renal or hepatic impairment: Use with caution. A lower or less-frequent dosing schedule may be required. Seizures: Use with caution in patients with a history of seizures. Suicide: Supervise depressed patients at risk during initial drug therapy.

 Administration/Storage

• Administer oral medication with food to minimize GI upset.
• Ensure that patient swallows capsule to avoid hoarding for suicide attempt.
• Capsules may be emptied and mixed with food or juice if patient has difficulty swallowing.
• Administer medication at least 6 hr before bedtime to prevent insomnia. Morning and early afternoon administration is advised.
• Store at room temperature. Avoid heat and moisture.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note recent use of MAOIs or history of drug or alcohol abuse.
• Assess vital signs and weight before beginning therapy and at regular intervals thereafter.
• Assess mental status, mood changes, affect, and suicidal tendencies daily.
• In patients with diabetes, monitor blood glucose levels before beginning and periodically during therapy.
• Assess for the following symptoms of blood dyscrasias: fever, sore throat, malaise, unusual bleeding, excessive bruising.
• Determine whether suicide precautions are advisable and implement them as necessary.
• Assist patient to ambulate and change positions to prevent postural hypotension.
• Weigh patient several times/wk on same scale at same time of day.
• Monitor I&O and evaluate bowel elimination.

Sarafem

• Reassess periodically to determine need for continued treatment.

 Patient/Family Education

• Instruct patient not to skip or double up on doses. Advise patient not to change dose except as directed by health care provider.
• Explain that improvement in mood and functioning may not be noted for several wk after initiation of drug therapy. Discuss fact that dosage may be increased or decreased by health care provider in effort to achieve optimal outcome.
• Instruct patient to avoid taking medication within 6 hr of bedtime as it may cause insomnia.
• Tell patient that doses over 20 mg can be taken as single dose or split into morning and noontime doses.
• Advise patient to take sips of water frequently, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
• Instruct patient to avoid sudden position changes to prevent orthostatic hypotension.
• Advise patients with diabetes that drug may cause loss of glycemic control.
• Instruct patient to report the following symptoms to health care provider: fever, malaise, unusual bleeding, excessive bruising, sore throat, persistent nausea or vomiting, severe headache, tachycardia, severe anorexia, weight loss.
• Advise patient to avoid caffeine, as this may increase stimulant effect of drug.
• Advise patient to avoid intake of alcoholic beverages or other CNS depressants (eg, analgesics, sedatives, antihistamines).
• Warn patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.
• Instruct patient not to take OTC medications without consulting health care provider.
• Advise patient to carry Medi-Alert information at all times describing medications being taken.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts