Pamifos (Pamidronate Disodium)

Pamifos ​​​​  ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​  acts ​ ​ ​  on ​ ​  bone ​ ​  resorption pathways ​ ​  and ​ ​  is ​ ​  indicated ​ ​  for:

• Hyper‑  ​ ​ ​ ​ ​ ​  calcemia of malignancy: reduces serum calcium levels.
• Bone  ​ ​ ​ ​ ​ ​  metastases from solid tumours: helps prevent skeletal‑related events.
• Paget’s disease of bone: normalises bone turnover.
• Osteolytic lesions in multiple myeloma: decreases bone loss.
• Osteoporosis (off‑label in some regions): supports bone density maintenance.

• Pamidronate disodium binds to hydroxyapatite crystals at sites of active bone remodeling. When osteoclasts attach to the drug‑coated bone surface, it disrupts their ruffled border, inhibits the mevalonate pathway, and triggers apoptosis, thereby reducing osteoclast‑mediated bone resorption and stabilising skeletal integrity.

Pamifos may cause a range of adverse reactions, most of which are dose‑related and infusion‑associated.

Common Side Effects

• Flu‑like symptoms: fever, chills, myalgia.
• Musculoskeletal pain: bone or joint discomfort.
• Nausea or vomiting.
• Transient elevation of serum creatinine.
• Injection site reactions: erythema or discomfort.

Serious or Rare Side Effects

• Acute renal failure: sudden loss of kidney function.
• Severe hypocalcaemia: dangerously low calcium levels.
• Osteonecrosis of the jaw (ONJ): exposed bone in the oral cavity.
• Atypical femoral fractures: stress fractures of the femur.
• Anaphylactic reactions: severe allergic response requiring immediate care.

Before initiating Pamifos therapy, clinicians should evaluate renal function, calcium status, and concomitant medications.

• Renal monitoring: assess serum creatinine and eGFR before each dose.
• Calcium supplementation: ensure adequate calcium and vitamin D intake.
• Concomitant nephrotoxins: avoid or adjust dosing of other renal‑impairing agents.
• Dental health: perform dental examination and treat infections before therapy.
• Pregnancy and lactation: use only if clearly needed; discuss risks with a specialist.
• Store at 2‑8°C: keep refrigerated, protect from light, do not freeze or shake.

Pamifos can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Aminoglycoside antibiotics: increase risk of nephrotoxicity.
• Loop diuretics (e.g., furosemide): may exacerbate hypocalcaemia.

Moderate Interactions (Monitor Closely)

• Non‑steroidal anti‑inflammatory drugs (NSAIDs): can affect renal clearance.
• Corticosteroids: may potentiate bone loss if not monitored.
• Calcium‑containing antacids: reduce pamidronate absorption if given concurrently.