dextroamphetamine sulfate

Action

Produces CNS and respiratory stimulation by promoting release of norepinephrine from nerve terminals

Availability

Capsules (sustained-release): 5 mg, 10 mg, 15 mg

Oral solution: 5 mg/ml

Tablets: 5 mg, 10 mg

Indications and dosages

➣ Attention deficit hyperactivity disorder

Adults: 5 to 60 mg P.O. daily in divided doses until optimal response is obtained

Children ages 6 and older: 5 mg (capsules, oral solution, or tablets) P.O. once or twice daily, increased by 5 mg at weekly intervals until optimal response is obtained

Children ages 3 to 5: 2.5 mg (oral solution) P.O. daily, increased by 2.5 mg at weekly intervals until optimal response is obtained

➣ Narcolepsy

Adults: 5 to 60 mg P.O. daily as a single dose or in divided doses

Children ages 12 and older: 10 mg P.O. daily, increased by 10 mg at weekly intervals until desired response occurs or adult dosage is reached

Children ages 6 to 11: 5 mg P.O. daily, increased by 5 mg at weekly intervals until desired response occurs or adult dosage is reached

Contraindications

• Hypersensitivity to drug or tartrazine

• Glaucoma

• Psychotic disorders, agitated states

• Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension

• Hyperthyroidism

• MAO inhibitor use within past 14 days

• Pregnancy or breastfeeding

Precautions

Use cautiously in:

• cardiovascular disease, hypertension, diabetes mellitus

• history of substance abuse

• elderly patients.

Administration

• Make sure patient swallows sustained-release capsules whole without chewing or crushing.

• Before starting therapy, perform complete cardiac evaluation, including ECG and echocardiogram.

• Give last daily dose at least 6 hours before patient's bedtime.

See Don't give within 14 days of MAO inhibitor, because potentially fatal reaction may occur.

Adverse reactions

CNS: hyperactivity, insomnia, restlessness, tremor, depression, dizziness, headache, irritability

CV: palpitations, tachycardia, hypertension, hypotension, arrhythmias

GI: nausea, vomiting, constipation, diarrhea, abdominal cramps, dry mouth

GU: erectile dysfunction, increased libido

Skin: urticaria

Other: metallic taste, decreased appetite, physical or psychological drug dependence

Interactions

Drug-drug. Acetazolamide, sodium bicarbonate: urine alkalization, leading to increased dextroamphetamine effects

Adrenergic blockers: additive effects

Ammonium chloride, ascorbic acid (large doses): urine acidification, leading to decreased dextroamphetamine effects

Beta-adrenergic blockers, tricyclic antidepressants: increased risk of adverse cardiovascular effects

Guanethidine: reversal of hypotensive effect

MAO inhibitors: hypertensive crisis

Phenothiazines: decreased dextroamphetamine effects

Selective serotonin reuptake inhibitors: increased risk of serotonin syndrome

Drug-diagnostic tests. Plasma corticosteroids: increased levels

Drug-food. Caffeine: increased stimulant effect

Drug-herbs. Caffeine-containing herbs, ephedra (ma huang): increased stimulant effect

Patient monitoring

• Interrupt therapy or reduce dosage periodically to assess drug efficacy in patients with behavior disorders.

• Monitor patient for new or worsening aggressive behavior.

• Monitor blood and urine glucose levels carefully in diabetic patient. Drug may alter regular insulin requirements.

Patient teaching

• Tell patient to swallow sustained-release capsules whole with liquid without chewing or crushing.

• Advise patient to take drug early in day to avoid insomnia.

See Instruct patient to immediately notify prescriber if chest pain, irregular pulse, or worsening aggressive behavior occurs.

• Instruct patient to avoid driving and other hazardous activities until he knows how drug affects him.

• Caution patient not to stop therapy abruptly but to taper dosage gradually.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.