ATOMOXETINE

ATOMOXETINe
(a-to-mox'e-teen)
Strattera
Classifications: psychotherapeutic agent, miscellaneous;
Therapeutic: adhd agent
Pregnancy Category: C

Availability

10 mg, 18 mg, 25 mg, 40 mg, 60 mg capsules

Action

Exact mechanism of action is unknown, but is thought to be related to selective inhibition of the pre-synaptic norepinephrine transporter, resulting in norepinephrine reuptake inhibition.

Therapeutic Effect

Improved attentiveness, ability to follow through on tasks with less distraction and forgetfulness, and diminished hyperactivity.

Uses

Treatment of attention deficit/hyperactivity disorder (ADHD) in adults and children.

Contraindications

Hypersensitive to atomoxetine or any of its constituents; concomitant use or use within 2 wk of MAOIs; narrow angle glaucoma; jaundice; suicidal ideation; pregnancy (category C).

Cautious Use

Severe liver injury may progress to liver failure or death in a small percentage of patients. Hypertension, tachycardia, cardiovascular or cerebrovascular disease; any condition that predisposes to hypotension; urinary retention or urinary hesitancy; concomitant use of CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine), albuterol or other beta-2 agonists, vasopressor drugs; history of bipolar disorder. Safety and efficacy in children <6 y and the older adult have not been established; lactation.

Route & Dosage

ADHD
Adult: PO Start with 40 mg in morning. May increase after 3 d to target dose of 80 mg/d given either once in the morning or divided morning and late afternoon/early evening. May increase to max of 100 mg/d if needed.
Child/Adolescent: PO <70 kg, start with 0.5 mg/kg/d. May increase after 3 d to target dose of 1.2 mg/kg/d. Administer once daily in morning or divide dose and give morning and late afternoon/early evening. Max dose is 1.4 mg/kg or 100 mg, whichever is less. >70 kg, the max total daily dose is 100 mg.

Hepatic Impairment
Child-Pugh Class B: Initial and target doses should be reduced to 50% of the normal dose.
Child-Pugh Class C: Initial dose and target doses should be reduced to 25% of normal.

Administration

Oral

Note that total daily dose in children and adolescents is based on weight. Determine that ordered dose is appropriate for weight prior to administration of drug.
Note manufacturer recommends dosage adjustments with concomitant administration of strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine). Consult physician.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Flu-like syndrome, flushing, fatigue, fever, rigors. CNS: Dizziness, headache, somnolence, crying, tearfulness, irritability, mood swings, insomnia, depression, tremor, early morning awakenings, paresthesias, abnormal dreams, decreased libido, sleep disorder, suicidal ideation. CV: Increased blood pressure, sinus tachycardia, palpitations. GI: Upper abdominal pain, constipation, dyspepsia, vomiting, decreased appetite, anorexia, dry mouth, diarrhea, flatulence, severe liver injury (rare). Endocrine: Hot flushes. Metabolic: Weight loss. Hepatic: Hepatotoxicity. Musculoskeletal: Arthralgia, myalgia. Respiratory: Cough, rhinorrhea, nasal congestion, sinusitis. Skin: Dermatitis, pruritus, increased sweating. Special Senses: Mydriasis. Urogenital: Urinary hesitation/retention, dysmenorrhea, ejaculation dysfunction, impotence, delayed onset of menses, irregular menstruation, prostatitis.

Interactions

Drug: Albuterol may potentiate cardiovascular effects of atomoxetine; fluoxetine, paroxetine, quinidine may increase atomoxetine levels and toxicity; maois may precipitate a hypertensive crisis; may attenuate effects of antihypertensive agents.

Pharmacokinetics

Absorption: Well absorbed from GI tract. Peak: 1–2 h. Metabolism: In liver by CYP2D6. Elimination: Primarily in urine. Half-Life: 5.2 h.

Nursing Implications

Assessment & Drug Effects

Evaluate for continuing therapeutic effectiveness especially with long-term use.
Monitor children and adolescents for behavior changes that may indicate suicidal ideation.
Monitor cardiovascular status especially with preexisting hypertension.
Monitor HR and BP at baseline, following a dose increase, and periodically while on therapy.
Lab tests: Periodic LFTs.
Report increased aggression and irritability as these may indicate a need to discontinue the drug.

Patient & Family Education

Instruct patients on S&S of liver toxicity.
Report any of the following to physician: chest pains or palpitations, urinary retention or difficulty initiating voiding urine, appetite loss and weight loss, or insomnia.
Make position changes slowly if you experience dizziness with arising from a lying or sitting position.
Do not drive or engage in potentially hazardous activities until reaction to the drug is known.

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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