title: Oral antihistamines reduce the side effects from rapid vancomycin infusion.
abstract: Rapid infusion of vancomycin causes histamine-mediated side effects, hypotension, and rash, known as "red man syndrome." In this prospective, randomized, double-blind, placebo-controlled study, we examined the ability of oral antihistamines to attenuate three clinical end points: rash, hypotension, and vancomycin discontinuation, and we compared these findings with those of a similar study using IV antihistamines. Patients (ASA physical status I-III) who required vancomycin prophylaxis for elective arthroplasty received either oral antihistamines (diphenhydramine < or = 1 mg/kg and cimetidine < or = 4 mg/kg, n = 20) or placebo (n = 10) 1 h before rapid vancomycin infusion (1 g over 10 min). The vancomycin infusion was discontinued if the mean arterial blood pressure decreased by > or = 20% or if itching was intolerable for the patient. Clinically significant hypotension developed in no treated patients, compared with five (50%) patients in the placebo group (P = 0.001). Rapid infusion was stopped for one treated patient (5%) and for five (50%) patients in the placebo group (P = 0.004). Incidence (P = 0.011) and severity of rash (P = 0.015) were also reduced in treated patients. Peak histamine levels were increased but were similar for patients in both groups (mean +/- SD, 1.9+/-2.5 vs 1.6+/-2.4 ng/mL; P = 0.75). Oral antihistamines were as effective as IV antihistamines. In conclusion, oral H1 and H2 antihistamine pretreatment is a practical, safe, and inexpensive option to attenuate histamine-mediated side effects associated with rapid vancomycin infusion.
  
  
  CONCLUSIONS
  Clinicians often must administer vancomycin faster than the 1-h recommended time, which can cause "red man syndrome" (rash, itching, hypotension). Our randomized, double-blind, placebo-controlled study showed that oral H1 and H2 antihistamine pretreatment significantly reduced the histamine-related side effects of rapid vancomycin infusion.
authors.affiliation: Department of Anesthesia and Critical Care, The University of Chicago, Illinois, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Renz
authors.forename: J D
authors.initials: JD
authors.lastname: Thurn
authors.forename: H A
authors.initials: HA
authors.lastname: Finn
authors.forename: J P
authors.initials: JP
authors.lastname: Lynch
authors.forename: J
authors.initials: J
authors.lastname: Moss
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006633:Histamine Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D014640:Vancomycin / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D000900:Anti-Bacterial Agents; D006633:Histamine Antagonists; D014640:Vancomycin