pamidronate disodium

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.

See 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.

See 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.

See Advise patient to promptly report significant respiratory problems, peripheral edema, or GI bleeding.

See 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.