H2-antihistamines for the treatment of anaphylaxis with and without shock: a systematic review.

BackgroundAnaphylaxis is a serious allergic or hypersensitivity reaction, which is rapid in onset and sometimes can prove fatal. Although H2-antihistamines are often administered for emergency treatment in anaphylaxis, there is uncertainty about their effectiveness in this disease.ObjectiveTo assess the benefits and harms of H2-antihistamines in the treatment of anaphylaxis.MethodsA systematic review was performed of randomized controlled trials and quasi-randomized controlled trials comparing H2-antihistamines with placebo or no intervention in patients with anaphylaxis.ResultsThe authors failed to identify any eligible studies for inclusion in this systematic review.ConclusionWhen H2-antihistamines are recommended for anaphylaxis treatment, the status of the evidence base supporting their use should be described. Well-designed randomized controlled trials investigating the role of H2-antihistamines in anaphylaxis treatment are urgently needed.