Sibutramine

INTRODUCTION

Indications

Treatment of obesity in patients with body mass index ≥30 kg/m² (or ≥27 kg/m² in patients with diabetes, hypertension, or other risk factors) in conjunction with other interventions (dietary restriction, exercise); used to produce and maintain weight loss.

Action

Acts as an inhibitor of the reuptake of serotonin, nor-epinephrine, and dopamine; increases the satiety-producing effects of serotonin. Therapeutic Effects: Decreased hunger with resultant weight loss in obese patients.

Adverse Reactions/Side Effects

CNS: SEIZURES, headache, insomnia, CNS stimulation, dizziness, drowsiness, emotional lability, nervousness. EENT: laryngitis/pharyngitis, rhinitis, sinusitis. CV: hypertension, palpitations, tachycardia, vasodilation. GI: anorexia, constipation, dry mouth, altered taste, dyspepsia, increased appetite, nausea. GU: dysmenorrhea. Derm: increased sweating, rash.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for new seizures or increased seizure activity, especially at the onset of drug treatment. Document the number, duration, and severity of seizures, and report these findings to the physician immediately.

• Be alert for signs of excessive CNS stimulation, including nervousness, 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 and drowsiness 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

• Implement therapeutic exercises (aerobic activities, resistive training) to complement the effects of drug therapy and help achieve optimal weight control.

• 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

• Instruct patient and family/caregivers to report other troublesome side effects, including severe or prolonged headache, sleep loss, skin problems (rash, sweating), nasal/pharyngeal/laryngeal irritation, menstrual abnormalities, or GI problems (nausea, constipation, altered taste, dry mouth, change in appetite).

Pharmacokinetics

Absorption: 77% absorbed, then rapidly undergoes extensive 1st-pass hepatic metabolism (via the P450 3A4 metabolic pathway) to active metabolites (M1 and M2).

Distribution: Widely and rapidly distributed; high concentrations in liver and ...