Drug information of Pamidronate

Pamidronate

Drug group:

Pamidronate is a bisphosphonate medicine that alters bone formation and breakdown in the body. Pamidronate is used to treat Paget's disease of bone. Pamidronate is also used to treat high blood levels of calcium caused by cancer (also called hypercalcemia of malignancy).

Pamidronate is also used to treat bone damage caused by certain types of cancer such as breast cancer or bone marrow cancer. Pamidronate does not treat the cancer itself.

Mechanism of effect

Bisphosphonate which inhibits bone resorption via actions on osteoclast activity, leading to an indirect increase in bone density.

Pharmacodynamic

Serum phosphate levels have been noted to decrease after administration of Pamidronate disodium, presumably because of decreased release of phosphate from bone and increased renal excretion as parathyroid hormone levels, which are usually suppressed in hypercalcemia associated with malignancy, return toward normal. Phosphate therapy was administered in 30% of the patients in response to a decrease in serum phosphate levels. Phosphate levels usually returned toward normal within 7 to 10 days.

Urinary calcium/creatinine and urinary hydroxyproline/creatinine ratios decrease and usually return to within or below normal after treatment with Pamidronate disodium. These changes occur within the first week after treatment.

Pharmacokinetics

Half-Life: 21-35 hours

Duration: hypercalcemia of malignancy (IV): 2 wk to 2 mth

Bioavailability: Poor; pharmacokinetic studies not available

Renal clearance: 49 mL/min

Excretion: Urine

Onset

  • Hypercalcemia of malignancy: Initial effect 1-2 days; max effect 5-7 days (IV)
  • Paget's disease: 1-3 months (maximum effect IV)

Dosage

owder for reconstitution

30mg

pamidronate injection solution as disodium

  • 3mg/mL
  • 6mg/mL
  • 9mg/mL

Hypercalcemia of Malignancy

Moderate hypercalcemia (ie, corrected serum calcium 12-13.5 mg/dL): 60-90 mg single-dose IV infusion over 2-24 hours

Severe hypercalcemia (ie, corrected serum calcium > 13.5 mg/dL): 90 mg single-dose IV infusion over 2-24 hours

Other information:

Longer infusions (ie, >2 hours) may decrease renal toxicity risk, especially with pre-existing renal insufficiency

May repeat after at least 7 days in patients showing partial or complete response if serum calcium does not remain in normal range

Paget's Disease

30 mg IV infused over 4 hours qDay for 3 consecutive days (ie, total cumulative dose 90 mg)

Osteolytic Bone Metastases of Breast Cancer

90 mg IV infusion over 2 hours q3-4Weeks

Osteolytic Bone Lesions of Multiple Myeloma

90 mg IV infusion over 4 hours qMonth

Prevention of Androgen Deprivation-induced Osteoporosis (Off-label)

60 mg IV infusion over 2 hours every 3 months or 90 mg administered once over 3-4 hours

Drug contraindications

pregnancy

Alerts

Electrolyte abnormalities and myelosuppression may occur

Increased risk of osteonecrosis of the jaw (advise patients against dental work during IV bisphosphonate treatment)

May cause fetal harm when administered to pregnant women; bisphosphonates are incorporated into the bone matrix and gradually released over periods of weeks to years

Points of recommendation

You should not use this medicine if you are allergic to mannitol, or to any bisphosphonate (alendronate, etidronate, ibandronate, pamidronate, risedronate, tiludronate, or zoledronic acid).

To make sure pamidronate is safe for you, tell your doctor if you have ever had:

  • an electrolyte imbalance (such as low levels of potassium or magnesium in your blood);
  • kidney disease;
  • liver disease; or
  • a dental problem (you may need a dental exam before you receive pamidronate).

In rare cases, this medicine may cause bone loss (osteonecrosis) in the jaw. Symptoms include jaw pain or numbness, red or swollen gums, loose teeth, or slow healing after dental work. The longer you use pamidronate, the more likely you are to develop this condition.

Pregnancy level

D


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