Dextroamphetamine

INTRODUCTION

Indications

Narcolepsy. Adjunct management of attention deficit hyperactivity disorder (ADHD). Unlabeled Use: Exogenous obesity.

Action

Produces CNS stimulation by releasing norepinephrine from nerve endings. Pharmacologic effects: CNS and respiratory stimulation, Vasoconstriction, Mydriasis (pupillary dilation), Contraction of the urinary bladder sphincter. Therapeutic Effects: Increased motor activity and mental alertness and decreased fatigue in narcoleptic patients. Increased attention span in ADHD.

Adverse Reactions/Side Effects

CNS: hyperactivity, insomnia, restlessness, tremor, behavioral disturbances, depression, dizziness, hallucinations, headache, irritability, mania, thought disorder. CV: palpitations, tachycardia, arrhythmias, hypertension. GI: anorexia, constipation, cramps, diarrhea, dry mouth, metallic taste, nausea, vomiting. GU: erectile dysfunction, increased libido. Derm: urticaria. Misc: physical dependence, psychologic dependence.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor attentiveness and behavior in patients with ADHD. Report any changes in attention and hyperactivity, and document whether this drug appears to be producing the desired effects.

• Monitor alertness in patients with narcolepsy; document the frequency and duration of sleeping episodes to help document the effects of drug therapy

• Be alert for signs of excessive CNS stimulation, including hyperactivity, restlessness, tremor, hallucinations, mania, irritability, or disordered thoughts. Report these signs to the physician.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report fast heart rate (tachycardia) or symptoms of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess blood pressure (BP) and compare to normal values (See Appendix F). Report a sustained increase in BP (hypertension).

• Assess dizziness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

Interventions

• Because of the risk of arrhythmias and abnormal BP responses, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (BP, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

Patient/Client-Related Instruction

• If used to promote weight loss, make sure patient has discussed this use with his/her physician. Advise patient about the potential cardiac and CNS risks of amphetamines, and counsel patient about safer methods for weight loss such as diet and exercise.

• Instruct patient and family/caregivers to report other troublesome side effects, including severe or prolonged headache, sleep loss, skin problems (hives, itching), sexual changes (increased libido, erectile dysfunction), or GI problems (nausea, vomiting, constipation, diarrhea, abdominal cramps, metallic taste, dry mouth).

Pharmacokinetics