PAMIDRONATE DISODIUM
| PAMIDRONATE DISODIUM (pa-mi'dro-nate) Aredia Classifications: bisphosphonate (regulatory, bone metabolism); Therapeutic: regulatory, bone metabolism Prototype: Etidronate Pregnancy Category: X |
Availability
30 mg, 60 mg, 90 mg injection
Action
A bone-resorption inhibitor thought to absorb calcium phosphate crystals into bone. May also inhibit osteoclast activity, thus contributing to inhibition of bone resorption. Does not inhibit bone formation or mineralization.
Therapeutic Effect
Reduces bone turnover and, when used in combination with adequate hydration, it increases renal excretion of calcium, thus reducing serum calcium concentrations.
Uses
Hypercalcemia of malignancy and Paget's disease, bone metastases in multiple myeloma.
Unlabeled Uses
Primary hyperparathyroidism, osteoporosis.
Contraindications
Hypersensitivity to pamidronate; breast cancer, severe renal disease, hypercalcemia, hypercholesterolemia, polycythemia, pregnancy (category D), prostatic cancer. Safety and effectiveness in children are not established.
Cautious Use
Heart failure, nephrosis or nephrotic syndrome, moderate renal disease; hepatic disease, cholestasis; peripheral edema, prostate hypertrophy; chronic kidney failure; lactation.
Route & Dosage
| Moderate Hypercalcemia of Malignancy (corrected calcium 12–13.5 mg/dL) Adult: IV 60–90 mg infused over 4–24 h, may repeat in 7 d Severe Hypercalcemia of Malignancy (corrected calcium >13.5 mg/dL) Adult: IV 90 mg infused over 4–24 h, may repeat in 7 d Paget's Disease, Metastases in Multiple Myeloma Adult: IV 30 mg once daily for 3 d (90 mg total) |
Administration
| Intravenous PREPARE: IV Infusion: ??Add 10 mL sterile water for injection to reconstitute the 30 or 90 mg vial to yield 3 or 9 mg/mL, respectively. Allow to completely dissolve. IV Infusion for Hypercalcemia of Malignancy: Withdraw the required dose and dilute in D5W, NS, or ?NS as follows: use 1000 mL. IV Infusion for Paget's Disease and Multiple Myeloma: Withdraw the required dose and dilute in D5W, NS, or ?NS as follows: use 500 mL. IV Infusion for Breast Cancer Bone Metastases: Withdraw the required dose and dilute in D5W, NS, or ?NS as follows: use 250 mL. ADMINISTER: IV Infusion: Regulate infusion rate carefully. Rapid infusion may cause renal damage. IV Infusion for Hypercalcemia of Malignancy: Infuse over 2–24 h. IV Infusion for Paget's disease and Multiple Myeloma: Infuse over 4 h. IV Infusion for Breast Cancer Bone Metastases: Infuse over 2 h. INCOMPATIBILITIES Solution/additive: calcium-containing solutions (including lactated Ringer's). |
- Refrigerate reconstituted pamidronate solution at 2°–8° C (36°–46° F); the IV solution may be stored at room temperature. Both are stable for 24 h.
Adverse Effects (≥1%)
Body as a Whole: Fever with or without rigors generally occurs within 48 h and subsides within 48 h despite continued therapy; thrombophlebitis at injection site; general malaise lasting for several weeks; transient increase in bone pain. Metabolic: Hypocalcemia. GI: Nausea, abdominal pain, epigastric discomfort. CV: Hypertension. Skin: Rash.Interactions
Drug: Concurrent use of foscarnet may further decrease serum levels of ionized calcium.Pharmacokinetics
Absorption: 50% of dose is retained in body. Onset: 24–48 h. Peak: 6 d. Duration: 2 wk–3 mo. Distribution: Accumulates in bone; once deposited, remains bound until bone is remodeled. Metabolism: Not metabolized. Elimination: 50% excreted in urine unchanged. Half-Life: 28 h.Nursing Implications
Assessment & Drug Effects
- Assess IV injection site for thrombophlebitis.
- Lab tests: Monitor serum calcium and phosphate levels, CBC with differential, Hct & Hgb, and kidney function tests throughout course of therapy.
- Monitor for S&S of hypocalcemia, hypokalemia, hypomagnesemia, and hypophosphatemia.
- Monitor for seizures especially in those with a preexisting seizure disorder.
- Monitor vital signs. Be aware that drug fever, which may occur with pamidronate use, is self-limiting, usually subsiding in 48 h even with continued therapy.
- Monitor I&O and hydration status. Patient should be adequately hydrated, without fluid overload.
Patient & Family Education
- Be aware that transient, self-limiting fever with/without chills may develop.
- Generalized malaise, which may last for several weeks following treatment, is an anticipated adverse effect.
- Report to physician immediately perioral tingling, numbness, and paresthesia. These are signs of hypocalcemia.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug