samarium Sm 153 lexidronam(sa-mar-ee-yum lex-i-droe-nam) ,
Pregnancy Category: D
ClassificationTherapeutic: nonopioid analgesics
Treatment of bone pain in patients with confirmed osteoblastic skeletal metastases that enhance on radionuclide bone scan.Ankylosing spondylitis, Paget’s disease, rheumatoid arthritis.
Preferentially taken up by bone tumors and metastatic bone lesions, where selective irradiation takes place.
Decreased pain from bony metastases.
Absorption: IV administration results in complete bioavailability.
Distribution: Taken up and is selectively retained by metastatic bone lesions.
Metabolism and Excretion: Unbound drug is excreted in urine.
Half-life: 65 min (radioactivity).
Time/action profile (pain relief)
Contraindicated in: Hypersensitivity; Obstetric / Lactation: Pregnancy or lactation.
Use Cautiously in: Women with childbearing potential; Diminished bone marrow reserve or other chronic debilitating illness (allow recovery from previous treatments); Patients with a life expectancy <6 mo; Pediatric: Children <16 yr (safety not established).
Adverse Reactions/Side Effects
- anemia (most frequent)
- neutropenia (most frequent)
- thrombocytopenia (most frequent)
- transient increase in bone pain
Drug-Drug interactionAdditive bone marrow toxicity with antineoplastics or previous radiation therapy.
Intravenous (Adults) 1 millicuries (mCi)/kg.
Radioactive Injection: 1850 megabecquerels/mL (50 mCi/mL) in 2 mL fill- and 3 mL fill-vials
- Assess pain (intensity, location) periodically during therapy. Patient may experience a transient increase in bone pain for 2–3 days beginning 2–3 days after administration. This is normal, and increasing analgesic doses may be required. Pain should begin to diminish after 1–2 wk or longer and may allow for reduction or discontinuation of analgesics. Effects may continue for several months.
- Lab Test Considerations: Beginning 2 wk after administration of samarium, monitor hematologic parameters (WBC, platelets) weekly for at least 8 wk and until adequate recovery of bone marrow function.
Potential Nursing DiagnosesAcute pain (Indications)
Deficient knowledge (Patient/Family Teaching)
- Should be administered only in facilities with personnel experienced in the safe use and handling of radiopharmaceuticals.
- Patient should drink or receive IV a minimum of 500 mL of fluids prior to injection. Instruct patient to void as often as possible following injection to minimize radiation exposure to bladder.
- Incontinent patients should have urinary catheters placed prior to administration to minimize the risk of radioactive contamination of clothing, linens, and the environment.
- Thaw at room temperature prior to administration; use within 8 hours of thawing or within 48 hours after time of calibration noted on the product label, whichever is earlier.
- Rate: Administer by slow injection over 1 min. Follow with a saline flush. A flushing sensation may be experienced following a rapid (<30 sec) injection
- Additive Incompatibility: Do not dilute or mix with other solutions or medications.
- Instruct patient to continue taking pain medication until samarium becomes effective. Analgesic doses may be decreased once the effects of samarium are known.
- Advise patient that no change in eating or drinking is necessary. Alcohol and caffeine need not be avoided unless advised by health care professional.
- Samarium is excreted in the urine for several hr after administration. Advise patient to use a normal toilet rather than a urinal if possible and to flush twice after use. Spilled urine or blood from a cut should be wiped up with a tissue and flushed. Good handwashing should be observed, and any linen contaminated with blood or urine should be immediately washed separately from other items and rinsed thoroughly or stored for 1–2 wk to allow for decay of samarium. If any urine collection device is used, the instructions on its use should be followed.
- Instruct male and female patients to use an effective form of contraception following samarium administration. May be harmful to fetus. Women of childbearing age should have a negative pregnancy test prior to administration of samarium.
- Instruct patient to notify any health care professional or caregiver of samarium therapy prior to treatment.
- Advise patient to contact health care professional if the effects of samarium decrease and pain returns.
- Emphasize the importance of periodic blood tests.
- Decrease in pain due to bony metastases.