Amphetamine Mixtures

INTRODUCTION

Indications

Narcolepsy. Attention deficit–hyperactivity disorder (ADHD).

Action

Causes release of norepinephrine from nerve endings. Pharmacologic effects are: CNS and respiratory stimulation, Vasoconstriction, Mydriasis (pupillary dilation). Therapeutic Effects: Increased motor activity, mental alertness, and decreased fatigue in narcoleptic patients. Increased attention span in ADHD.

Adverse Reactions/Side Effects

CNS: hyperactivity, insomnia, restlessness, tremor, behavioral disturbances, dizziness, hallucinations, headache, mania, irritability, thought disorder. CV: palpitations, tachycardia, cardiomyopathy (increased with prolonged use, high doses), hypertension, hypotension. GI: anorexia, constipation, cramps, diarrhea, dry mouth, metallic taste, nausea, vomiting. GU: erectile dysfunction, increased libido. Derm: urticaria. Endo: growth inhibition (with long term use in children). Misc: psychologic dependence.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

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

• 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 assess the effects of drug therapy.

• 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 and compare to normal values (See Appendix F). Report changes in blood pressure, either a problematic decrease in BP (hypotension), or a sustained increase in BP (hypertension).

• Be alert for signs of cardiomyopathy, especially at high doses for prolonged periods. Signs include breathlessness with exertion, fatigue, dizziness, palpitations, and peripheral and pulmonary edema. Report these signs to the physician.

• Assess growth rate in children receiving chronic therapy; report delayed or stunted growth to the physician.

Interventions

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

Patient/Client-related Instruction

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

Pharmacokinetics

Absorption: Well absorbed after oral administration.

Distribution: Widely distributed in body tissues, with high concentrations in ...