Romiplostim

INTRODUCTION

Indications

Treatment of thrombocytopenia associated with chronic immune (idiopathic) thrombocytopenic purpura that has not responded to corticosteroids, immunoglobulins, or splenectomy where there is risk of bleeding.

Action

Acts as thrombopoietin (TPO) receptor agonist. Therapeutic Effects: Improved platelet count with decreased sequelae of thrombocytopenia (bleeding).

Adverse Reactions/Side Effects

CNS: dizziness, insomnia, headache. GI: abdominal pain, dyspepsia. Hemat: bone marrow fibrosis, thrombosis/thromboembolism (dose related). MS: extremity pain, myalgia, arthralgia, shoulder pain. Neuro: paresthesia.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor abnormal blood coagulation, including venous thrombosis (lower extremity swelling, warmth, erythema, tenderness), arterial thrombosis (extreme coldness in the hands and feet, cyanosis, muscle cramping), and pulmonary embolism (shortness of breath, chest pain, cough, bloody sputum). Notify physician immediately, and request objective tests (Doppler ultrasound, others) if thrombosis is suspected.

• Monitor signs of anemia caused by bone marrow fibrosis. Signs include unusual fatigue, shortness of breath with exertion, pallor, and bruising. Notify physician immediately if these signs occur.

• Assess any muscle, joint, or extremity pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.

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

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

Interventions

• Because of the risk of thromboembolism, 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).

• If administered via local (subcutaneous) injection, do not apply massage or physical agents (heat, cold, electrotherapeutic modalities) at or near the application site. These interventions can affect drug absorption from subcutaneous tissues.

Patient/Client-Related Instruction

• Caution patient and family/caregivers about risks of thromboembolism, and review warning signs of these problems (see above under Evaluation and Examination).

• Instruct patient to report other troublesome side effects such as severe or prolonged headache, sleep loss, or GI problems (indigestion, abdominal pain).

Pharmacokinetics

Absorption: Well absorbed following subcutaneous administration.

Distribution: Binds to specific cellular receptors.

Metabolism and Excretion: Unknown.

Half-life: 1–34 days.