pamidronate

Absorption: IV administration results in complete bioavailability.

Distribution: Rapidly absorbed by bone. Reaches high concentrations in bone, liver, spleen, teeth, and tracheal cartilage. Approximately 50% of a dose is retained by bone and then slowly released.

Metabolism/Excretion: 50% is excreted unchanged in the urine.

Half-Life: Elimination half-life from plasma is biphasic—1st phase 1.6 hr, 2nd phase 27.2 hr. Elimination half-life from bone is 300 days.

Time/Action Profile ⬆ ⬇

(effect on serum calcium)

ROUTE	ONSET	PEAK	DURATION
IV	24 hr	7 days	unknown

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to pamidronate, other bisphosphonates, or mannitol;
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Underlying cardiovascular disease, especially HF (initiate saline hydration cautiously);
Invasive dental procedures, cancer, receiving chemotherapy or corticosteroids, poor oral hygiene, periodontal disease, dental disease, anemia, coagulopathy, infection, or poorly fitting dentures (may ↑ risk of jaw osteonecrosis);
History of thyroid surgery (may be at ↑ risk for hypocalcemia);
Renal impairment (dose ↓ recommended);
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: arrhythmias, hypertension, syncope, tachycardia

EENT: blurred vision, conjunctivitis, eye pain/inflammation, rhinitis

Endo: hypothyroidism

F and E: hypocalcemia, hypokalemia, hypomagnesemia, hypophosphatemia, fluid overload

GI: nausea, abdominal pain, anorexia, constipation, vomiting

GU: nephrotoxicity

Hemat: leukopenia, anemia

Local: phlebitis at injection site

MS: muscle stiffness, pain, femur fractures, osteonecrosis (primarily of jaw)

Neuro: fatigue

Resp: rales

Misc: fever

Interactions ⬆ ⬇

Drug-drug:

Hypokalemia and hypomagnesemia may ↑ risk of digoxin toxicity.
Calcium and vitamin D will antagonize the beneficial effects of pamidronate.
Concurrent use of thalidomide may ↑ risk of renal impairment.

Route/Dosage ⬆ ⬇

Hypercalcemia of Malignancy

IV (Adults ): Moderate hypercalcemia: 30–90 mg; may be repeated after 7 days.

Osteolytic Lesions from Multiple Myeloma

IV (Adults ): 90 mg monthly.

Osteolytic Lesions from Metastatic Breast Cancer

IV (Adults ): 90 mg every 3–4 wk.

Paget’s Disease

IV (Adults ): 90–180 mg/treatment; may be given as 30 mg daily for 3 days up to 30 mg/wk for 6 wk. Single doses of 60–90 mg may also be effective.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 3 mg/mL; 6 mg/mL; 9 mg/mL

Assessment ⬆ ⬇

Monitor intake/output ratios and BP frequently during therapy. Assess for signs of fluid overload (edema, rales/crackles).
Monitor symptoms of hypercalcemia (nausea, vomiting, anorexia, weakness, constipation, thirst, and cardiac arrhythmias).
Observe for evidence of hypocalcemia (paresthesia, muscle twitching, laryngospasm, and Chvostek’s or Trousseau’s sign). Protect symptomatic patients by elevating and padding side rails; keep bed in low position.
Monitor IV site for phlebitis (pain, redness, swelling). Symptomatic treatment should be used if this occurs.
Assess for bone pain. Treatment with nonopioid or opioid analgesics may be necessary.

Lab Test Considerations:

Assess serum creatinine prior to each treatment. Withhold dose if renal function has deteriorated in patients treated for bone metastases.
- Monitor serum electrolytes (including calcium, phosphate, potassium, and magnesium), hemoglobin, and creatinine closely. Monitor CBC and platelet count during the first 2 wk of therapy. May cause hyperkalemia or hypokalemia, hypernatremia, and hematuria.
- Monitor renal function periodically during therapy.

Implementation ⬆ ⬇

Initiate a vigorous saline hydration, maintaining a urine output of 2000 mL/24 hr, concurrently with pamidronate therapy. Patients should be adequately hydrated, but avoid overhydration. Use caution in patients with underlying cardiovascular disease, especially HF. Do not use diuretics prior to treatment of hypovolemia.
- Patients with severe hypercalcemia should be started at the 90-mg dose.

IV Administration:

Hypercalcemia: Diluent: Dilute recommended dose in 1000 mL of 0.45% NaCl, 0.9% NaCl, or D5W. Solution is stable for 24 hr at room temperature.
Rate: Administer 60-mg infusion over at least 4 hr and 90-mg infusion over 24 hr.
Multiple Myeloma: Diluent: Dilute recommended dose in 500 mL of 0.45% NaCl, 0.9% NaCl, or D5W.
Rate: Administer over 4 hr.
Paget’s Disease: Dilute recommended dose in 500 mL of 0.45% NaCl, 0.9% NaCl, or D5W.
Rate: Administer over 4 hr.

Patient/Family Teaching ⬆ ⬇

Advise patient to report signs of hypercalcemic relapse (bone pain, anorexia, nausea, vomiting, thirst, lethargy) or eye problems (pain, inflammation, blurred vision, conjunctivitis) to health care professional promptly.
Advise patient to notify nurse of pain at the infusion site.
Encourage patient to comply with dietary recommendations. Diet should contain adequate amounts of calcium and vitamin D.
Advise patient to notify health care professional if bone pain is severe or persistent.
Advise patient to maintain good oral hygiene and have regular dental examinations. Instruct patient to inform health care professional of pamidronate therapy prior to dental surgery.
Emphasize the need for keeping follow-up exams to monitor progress, even after medication is discontinued, to detect relapse.
Rep: May cause fetal harm. Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected and to avoid breastfeeding during therapy. May impair female and male fertility.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇