Samarium Sm 153 Lexidronam
(sa MAR ee um es em won fif tee three lex ID roe nam)
- Samarium-153 Lexidronam
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Quadramet: 1850 MBq/mL (3 mL)
Brand Names: U.S.
Samarium Sm-153 EDTMP has an affinity for bone and concentrates in areas of bone turnover in association with hydroxyapatite. Samarium Sm-153 EDTMP is taken up at the site of the bone metastases to deliver local radiation. In studies, samarium accumulated ~5 times more in osteoblastic lesions than in normal bone.
Excretion: Urine (34.5% ± 15.5% in the first 6 hours)
Onset of Action
Pain relief: 1 week; maximum pain relief occurs at 3 to 4 weeks
Use: Labeled Indications
Osteoblastic metastatic bone lesion pain: Relief of pain associated with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan.
Known hypersensitivity to ethylenediaminetetramethylenephosphonic acid (EDTMP), similar phosphonate compounds, or any component of the formulation
Note: Dose adjustments for extremes of weight have not been studied; use caution when determining dose for very thin or obese patients.
Osteoblastic metastatic bone lesion pain: IV: 1 mCi/kg (37 MBq/kg)
Dosing: Renal Impairment
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); use with caution, patients with renal insufficiency may not tolerate the recommended hydration.
Dosing: Hepatic Impairment
There are no dosage adjustments provided in the manufacturer's labeling. However, a need for dosage adjustment is unlikely since studies have not revealed hepatic excretion.
Radiopharmaceutical; use appropriate precautions for handling and disposal. Wear gloves and use adequate shielding for handling and administration. Measure the appropriate dose using a suitable radioactivity calibration system immediately prior to administration. Do not dilute or mix with other solutions. Thaw at room temperature prior to administration.
IV: Administer over 1 minute through a secure in-dwelling catheter, followed by a saline flush. Do not dilute or mix with other solutions. Give 500 mL of fluids (IV or orally) prior to administration. To minimize bladder exposure, patients should void as soon as possible after injection. Precautions should be taken for 12 hours following administration. If possible, patients should urinate in a toilet (rather than a urinal); flush the toilet several times after each use. Promptly clean any spilled urine; if blood or urine is on clothing, wash separately or store for 1 to 2 weeks to allow for radioactive decay.
Radiopharmaceutical; use appropriate precautions for handling and disposal.
Store frozen at -10°C to -20°C (14°F to -4°F) in a lead-shielded container. Product expires within 56 hours of calibration or within 8 hours of thawing, whichever occurs earlier.
>10%: Hematologic: Thrombocytopenia (69%), leukopenia (59%), anemia (41%)
1% to 10%:
Cardiovascular: Arrhythmias, hypertension, stroke
Central nervous system: Dizziness
Neuromuscular & skeletal: Bone pain, spinal cord compression
Respiratory: Bronchitis, epistaxis
Concerns related to adverse effects:
• Bone marrow suppression: May cause myelosuppression (leukopenia, thrombocytopenia, and anemia). White blood cell and platelet nadir usually occur within 3 to 5 weeks, with recovery by 8 weeks; monitor blood counts for at least 8 weeks or until adequate marrow recovery. Consider current hematologic status and history of myelosuppressive response to other myelotoxic agents prior to therapy. Due to potential for additive hematologic toxicity, avoid concurrent chemotherapy and external beam radiation therapy unless benefits outweigh risks.
• Bone pain flare: A transient increase in bone pain (usually mild) occurring within 3 days of administration has been reported in some patients; may be managed with analgesics.
• Disseminated intravascular coagulation (DIC): Active DIC may be a risk factor for severe thrombocytopenia following therapy; deaths have occurred in patients with DIC receiving beta-emitting radiopharmaceuticals.
• Heart failure: Use with caution in patients with heart failure; recommended hydration to promote urinary excretion may be poorly tolerated and may require additional supportive management.
• Hypocalcemia: Use with caution in patients at risk for developing hypocalcemia (low calcium levels have been reported).
• Incontinence: Incontinent patients may require urinary catheterization to reduce the risk of radioactive contamination of clothes or bed linens.
• Renal insufficiency: Use with caution in patients with renal insufficiency; recommended hydration to promote urinary excretion may be poorly tolerated and may require additional supportive management.
• Weight extremes: Dose adjustments for extremes of weight have not been studied; use caution when determining dose for very thin or obese patients.
• Radiopharmaceutical: Use appropriate precautions for handling, disposal, and minimizing exposure to patients and healthcare personnel. Use under supervision of individuals with experience/training in the handling of radioactive materials approved by the applicable regulatory authority.
• Appropriate use: Verify the radioactivity dose to be administered prior to administration. Patients should not be released until their radioactivity levels and exposure rates comply with federal and local regulations. Samarium Sm 153 lexidronam will not prevent and is not indicated for the treatment of spinal cord compression.
• Latex: Vial stopper may contain latex.
CBC with differential and platelets weekly for at least 8 weeks (or until adequate marrow recovery); signs/symptoms of disseminated intravascular coagulation (DIC); signs/symptoms of hypocalcemia (in patients at risk for developing hypocalcemia); fluid status in patients with renal insufficiency or heart failure
Pregnancy Risk Factor
Animal reproduction studies have not been conducted. Radiopharmaceuticals have the potential to cause fetal harm. Women of reproductive potential should have a negative pregnancy test prior to treatment and avoid becoming pregnant during or soon after treatment. Both males and females should use effective contraception following treatment.
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience diarrhea or increased bone pain. Have patient report immediately to prescriber signs of infection, signs of bleeding (vomiting blood or vomit that looks like coffee grounds; coughing up blood; blood in the urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a reason or that get bigger; or any bleeding that is very bad or that will not stop), severe loss of strength and energy, arrhythmia, or burning or numbness feeling (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.