pamidronate disodium
Pharmacologic class: Bisphosphonate, hypocalcemic
Therapeutic class: Bone resorption inhibitor
Pregnancy risk category C
Action
Inhibits normal and abnormal bone resorption and decreases calcium levels
Availability
Injection: 30 mg/vial, 90 mg/vial
Indications and dosages
➣ Hypercalcemia caused by cancer
Adults: For moderate hypercalcemia, 60 to 90 mg as a single-dose I.V. infusion over 2 to 24 hours. For severe hypercalcemia, 90 mg as a single-dose I.V. infusion over 2 to 24 hours.
➣ Osteolytic lesions caused by multiple myeloma
Adults: 90 mg I.V. as a 4-hour infusion q month
➣ Osteolytic bone metastases of breast cancer
Adults: 90 mg I.V. as a 2-hour infusion q 3 to 4 weeks
➣ Paget's disease
Adults: 30 mg I.V. daily as a 4-hour infusion for 3 days
Contraindications
• Hypersensitivity to drug, its components, or other bisphosphonates
Precautions
Use cautiously in:
• renal impairment
• pregnant or breastfeeding patients
• children (safety not established).
Administration
• Hydrate patient with saline solution as needed before starting therapy.
• Because of risk of renal failure, give no more than 90 mg in single doses.
☞ Reconstitute vial using 10 ml of sterile water for injection. When completely dissolved, dilute in 250 to 1,000 ml of half-normal or normal saline solution or dextrose 5% in water.
☞ Don't mix with solutions containing calcium, such as lactated Ringer's solution.
• Administer in I.V. line separate from all other drugs and fluids.
Adverse reactions
CNS: anxiety, headache, insomnia, psychosis, drowsiness, weakness
CV: hypertension, syncope, tachycardia, atrial flutter, arrhythmias, heart failure
EENT: sinusitis
GI: nausea, vomiting, diarrhea, abdominal pain, constipation, dyspepsia, stomatitis, anorexia, GI hemorrhage
GU: urinary tract infection
Hematologic: anemia, neutropenia, leukopenia, granulocytopenia, throm-bocytopenia
Metabolic: hypothyroidism
Musculoskeletal: bone pain, joint pain, myalgia
Respiratory: crackles, coughing, dyspnea, upper respiratory infection, pleural effusion
Other: fever, generalized pain, injection site reaction
Interactions
Drug-diagnostic tests. Creatinine: increased level
Electrolytes, hemoglobin, magnesium, phosphorus, platelets, potassium, red blood cells, white blood cells: decreased levels
Patient monitoring
• Monitor hydration status carefully.
• Monitor vital signs and ECG. Evaluate cardiovascular and respiratory status closely.
• Assess hematologic studies and creatinine level before each treatment course.
• Assess electrolyte levels, especially calcium, magnesium, and phosphorus.
• Closely monitor fluid intake and output. Watch for signs and symptoms of urinary tract infection.
Patient teaching
• Instruct patient to weigh himself regularly and report sudden gains.
☞ Advise patient to promptly report significant respiratory problems, peripheral edema, or GI bleeding.
☞ Inform patient that drug lowers resistance to some infections. Tell him to immediately report fever and other signs and symptoms of infection.
• Explain importance of undergoing laboratory tests before, during, and after therapy.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, cognition, and alertness.
• Tell patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.