title: Samarium 153Sm lexidronam.
abstract: Samarium 153Sm lexidronam is a medium energy beta-emitting radioisotope chelated to the tetraphosphate, ethylenediaminetetramethylenephosphonic acid (EDTMP). 153Sm has a physical half-life of 1.9 days. Samarium 153Sm lexidronam concentrates in bone tissue and has a metastatic lesion: normal bone ratio of 4. Clearance of nonskeletal radioactivity after administration of samarium 153Sm lexidronam is rapid, and is almost complete from the blood and urine within 1 and 6 hours, respectively. Some degree of pain relief was achieved in 72% of patients with bone metastases after a single dose of samarium 153Sm lexidronam 1 mCi/kg (37 MBq/kg) compared with 44% of placebo recipients (p < 0.025). Relief was generally attained within 2 weeks and lasted for a median of 8 to 15 weeks. After recurrence of pain, a second dose of samarium 153Sm lexidronam may produce further pain relief in some patients. The dose-limiting toxicity of samarium 153Sm lexidronam is reversible myelosuppression.
authors.affiliation: Adis International Limited, Auckland, New Zealand. demail@adis.co.nz
authors.forename: H M
authors.initials: HM
authors.lastname: Lamb
authors.forename: D
authors.initials: D
authors.lastname: Faulds
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000493:pharmacokinetics* / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D006207:Half-Life; D006801:Humans; D009942:Organometallic Compounds / Q000493:pharmacokinetics* / Q000494:pharmacology* / Q000627:therapeutic use; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics* / Q000494:pharmacology* / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy*; D011868:Radioisotopes / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D014018:Tissue Distribution
chemical_list: D018712:Analgesics, Non-Narcotic; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D011868:Radioisotopes; C061972:samarium Sm-153 lexidronam