Dronabinol

INTRODUCTION

Indications

Prevention of serious nausea and vomiting from cancer chemotherapy when other more conventional agents have failed. Management of anorexia associated with weight loss in patients with AIDS.

Action

Active ingredient in marijuana. Has a wide variety of CNS effects, including inhibition of the vomiting control mechanism in the medulla oblongata. Therapeutic Effects: Suppression of nausea and vomiting. Increased appetite in patients with AIDS.

Adverse Reactions/Side Effects

CNS: anxiety, concentration difficulty, confusion, dizziness, drowsiness, mood change, abnormal thinking, depression, disorientation, hallucinations, headache, impaired judgment, memory lapse, paranoia. EENT: dry mouth. CV: palpitations, syncope, tachycardia. GI: abdominal pain, nausea, vomiting. Derm: facial flushing. Neuro: ataxia, paresthesia. Misc: physical dependence, psychologic dependence (high doses or prolonged therapy).

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor improvements in GI symptoms (decreased nausea and vomiting, increased appetite) to help determine if drug therapy is successful.

• Assess dizziness, drowsiness, or ataxia 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.

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

• Monitor changes in mood and behavior such as anxiety, confusion, depression, disorientation, paranoia, memory lapses, impaired concentration, and hallucinations. Notify physician if these changes become problematic.

• Assess signs of paresthesia, including numbness, tingling, and muscle weakness. Perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

Interventions

• Because of the risk of arrhythmias, 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

• Advise patient about the risk of daytime drowsiness and decreased attention and mental focus. Use care if driving or in other activities that require strong concentration.

• Educate patient about the risk of physical and psychologic dependence during excessive or prolonged use; encourage patient to adhere to proper dosing schedule.

• Instruct patient to report bothersome GI side effects such as severe or prolonged nausea, vomiting, abdominal pain, or dry mouth.

Pharmacokinetics

Absorption: Extensively metabolized following absorption, resulting in poor bioavailability (10–20%).

Distribution: Enters breast milk in high concentrations. Highly lipid soluble. Persists in ...