title: Magnesium monitoring practice in monoclonal anti-epidermal growth factor receptor antibodies therapy.
abstract: OBJECTIVE
  It is now estimated that about 5% of cetuximab-treated patients and about 3% of panitumumab-treated patients will develop grade 3-4 hypomagnesemia. The aim of this study was to assess the extent of magnesium monitoring in patients treated with epidermal growth factor receptor (EGFR)-targeting antibodies and to estimate the incidence of hypomagnesemia in these patients at our institution.
  
  
  METHODS
  A 2-year retrospective study was carried out. At least four doses of weekly cetuximab or two doses of bi-weekly panitumumab were required for inclusion. Serum magnesium profiles were reviewed from 1 month before treatment until 3 months after treatment discontinuation, and patients with <2 determinations were excluded.
  
  
  CONCLUSIONS
  Two hundred and one patients received at least one dose of EGFR-targeting antibodies, but only 68 met the inclusion criteria. Seventy patients had <2 magnesium determinations. The overall hypomagnesemia was 58·82% (40 of 68 patients), with a 4·41% grade 3 hypomagnesemia (three of 68 patients). No grade 4 hypomagnesemia was detected.
  
  
  CONCLUSIONS
  There is a lack of magnesium monitoring in these patients. Serum magnesium determinations should be done every 4-8 weeks in patients treated with EGFR-targeting antibodies, as it is a useful surrogate marker for both toxicity and efficacy.
authors.affiliation: Pharmacy Department, Hospital Clinic de Barcelona, Barcelona, Spain. fdopazo@clinic.ub.es
authors.forename: F
authors.initials: F
authors.lastname: do Pazo-Oubiña
authors.forename: A
authors.initials: A
authors.lastname: Estefanell-Tejero
authors.forename: G
authors.initials: G
authors.lastname: Riu-Viladoms
authors.forename: H
authors.initials: H
authors.lastname: Anglada-Martínez
authors.forename: G
authors.initials: G
authors.lastname: Molas-Ferrer
authors.forename: N
authors.initials: N
authors.lastname: Creus-Baró
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000009:adverse effects*; D000068818:Cetuximab; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000276:immunology*; D005260:Female; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D000077544:Panitumumab; D012189:Retrospective Studies
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000077544:Panitumumab; D066246:ErbB Receptors; D008274:Magnesium; D000068818:Cetuximab