Samarium Sm 153 Lexidronam

INTRODUCTION

Indications

Treatment of bone pain in patients with confirmed osteoblastic skeletal metastases that enhance on radionuclide bone scan. Unlabeled Use: Ankylosing spondylitis, Paget's disease, rheumatoid arthritis.

Action

Preferentially taken up by bone tumors and metastatic bone lesions, where selective irradiation takes place. Therapeutic Effects: Decreased pain from bony metastases.

Adverse Reactions/Side Effects

CV: arrhythmias, hypertension. Hemat: anemia, neutropenia, thrombocytopenia. MS: transient increase in bone pain.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report any rhythm disturbances or symptoms of increased 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).

• Be alert for neutropenia (fever, sore throat, signs of infection), thrombocytopenia (bruising, nose bleeds, and bleeding gums), or unusual weakness and fatigue that might be due to anemia. Notify physician or nursing staff of these symptoms.

• Assess musculoskeletal pain and other variables (range of motion, muscle strength) to document whether this drug is successful in helping manage the patient's pain and decreasing impairments. Monitor any transient increase in bone pain, and report a sustained or severe increase in musculoskeletal pain.

Interventions

• Implement appropriate manual therapy techniques, physical agents, and therapeutic exercises to reduce pain and decrease the need for analgesic drugs.

• 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).

• Help patient explore other nonpharmacologic methods to reduce chronic pain, such as relaxation techniques, exercise, counseling, and so forth

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.

Distribution: Taken up and is selectively retained by metastatic bone lesions.

Metabolism and Excretion: Unbound drug is excreted in urine.

Half-life: 65 min (radioactivity).

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Pregnancy or lactation.

Use Cautiously in: Women with childbearing potential; Diminished bone marrow reserve or other chronic debilitating illness (allow recovery from previous treatments); Patients with a life expectancy <6 mo; Children <16 yr (safety not established).

Interactions

Drug-Drug:...