QUADRAMET
Clinical safety rating: caution
Comprehensive clinical and safety monograph for QUADRAMET (QUADRAMET).
Samarium Sm 153 lexidronam is a radiolabeled agent that localizes to areas of osteoblastic bone activity. The samarium-153 isotope emits beta particles and gamma photons, delivering radiation to the bone and surrounding tissues. This results in the destruction of malignant cells in bone metastases.
| Metabolism | Samarium Sm 153 lexidronam is cleared from the blood primarily by the kidneys. No significant hepatic metabolism occurs. |
| Excretion | Renal: 65% as unchanged drug; biliary/fecal: 20% as metabolites; remainder as other minor metabolites. |
| Half-life | Terminal half-life: 6–8 hours (prolonged in renal impairment; may exceed 20 hours in CrCl <30 mL/min). |
| Protein binding | 92% (primarily to albumin). |
| Volume of Distribution | 0.5–1.0 L/kg (reflects moderate tissue distribution). |
| Bioavailability | Oral: 25–35% (first-pass effect); IV: 100%. |
| Onset of Action | Oral: 1–2 hours; IV: Immediate (5–10 minutes). |
| Duration of Action | 12–24 hours (dose-dependent; extended with hepatic dysfunction). |
1.0 mCi/kg (37 MBq/kg) intravenously as a single dose.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated if GFR < 30 mL/min; use with caution and consider dose reduction if GFR 30-60 mL/min. |
| Liver impairment | No specific Child-Pugh based modifications available; contraindicated in severe hepatic impairment. |
| Pediatric use | Not recommended for use in pediatric patients due to lack of safety and efficacy data. |
| Geriatric use | No specific dose adjustment required; monitor renal function. Caution due to potential age-related renal impairment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for QUADRAMET (QUADRAMET).
| Breastfeeding | No human data. Radioactive compound; likely excreted in milk. Advise to discontinue breastfeeding or avoid use. M/P ratio not available. |
| Teratogenic Risk | QUADRAMET (samarium-153 lexidronam) is radioactive and emits beta particles. There is no human data; however, based on mechanism, it causes DNA damage. Use is contraindicated in pregnancy. Potential fetal harm in all trimesters, including malformations, growth retardation, and neonatal death. Abortifacient effects possible. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to samarium Sm 153 lexidronam or any component of the product","Pregnancy (Category D: known to cause fetal harm)","Nursing mothers (discontinue nursing or discontinue drug)"]
| Precautions | ["Bone marrow suppression, including thrombocytopenia and neutropenia, is the primary dose-limiting toxicity.","Monitor complete blood counts (CBC) weekly for at least 8 weeks after administration.","Not intended for use in patients with significant bone marrow compromise.","Use caution in patients with impaired renal function as drug clearance may be reduced."] |
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| Not applicable due to contraindication. If inadvertently used, monitor fetal exposure via radiation dosimetry and consult radiation safety officer. Assess for fetal growth and development. Maternal complete blood counts, renal function, and vital signs. |
| Fertility Effects | May cause temporary or permanent infertility due to radiation exposure to gonads. Spermatogenesis and oogenesis impairment. Preclinical data show testicular atrophy and ovarian depletion. |