Pamidronate disodium
Class: bisphosphonate calcium regulator
Indications: hypercalcaemia of malignancy; osteolytic lesions and bone pain with bone metastases or multiple myeloma
Contraindications/cautions: severe renal impairment, dental surgery, oral disease, ensure adequate hydration; caution in severe hepatic impairment
Adverse reactions: less common: transient flu-like symptoms, slight increase in temperature, fever, hypocalcaemia, transient bone pain, nausea, headache, osteonecrosis (particularly of jaw); GI upset, hypertension
Metabolism/clearance: not metabolised, excreted by the kidneys after uptake into the bone
Interactions:
- incompatible with calcium containing infusion fluids
| Dosing: | |
|---|---|
| oral: | not available |
| subcut: | zoledronic acid is usually used instead |
| rectal: | not available |
| iv infusion: | bone pain 90 mg every 3 to 4 weeks hypercalcaemia 15 to 90 mg depending on corrected calcium concentration (see below) |
- rate of infusion should not exceed 60 mg/hour (20 mg/hour in renal impairment) and concentration should not exceed 90 mg/250 mL
Syringe driver: not applicable
Renal impairment: maximum infusion rate 20 mg/hour; avoid if CrCl < 30 mL/min except in life-threatening hypercalcaemia if benefit outweighs risk
Mechanism of action: bisphosphonates are adsorbed onto hydroxyapatite sites in bone, reducing osteoclast bone resorption and therefore reducing rate of bone turnover
Onset: hypercalcaemia: 1 to 2 days
Duration: hypercalcaemia: 2 weeks to 3 months bone pain: 3 to 4 weeks
Notes:
- 50% of patients with metastatic bone pain may be responsive
- Hypercalcaemia of malignancy (slow IV infusion):
Adult – according to initial serum Ca conc:
- Serum calcium <3 mmol/L – 15 to 30 mg
- Serum calcium 3 to 3.5mmol/L – 30 to 60 mg
- Serum calcium 3.5 to 4mmol/L – 60 to 90 mg
- Serum calcium > 4mmol/L – 90 mg