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PRACTICE: D A Andreae and M H Andreae Should antihistamines be used to treat anaphylaxis? BMJ 2009; 339: b2489 [Full text]

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There is a trial of promethazine

Arun S. Nanivadekar   (12 July 2009)

Re: Re: There is a trial of promethazine

Doerthe A Andreae, Michael H Andreae   (16 July 2009)

What primary outcome for an antihistamine trial

Simon G A Brown   (3 August 2009)

There is a trial of promethazine 12 July 2009
Arun S. Nanivadekar, Medical Research Consultant C-2, Flushel Apts, 21 Road, Bandra (W), Mumbai 400 050, India Send response to journal: Re: There is a trial of promethazine	I have read a trial of promethazine vs. placebo for prevention of anaphylaxis following anti-snake venom, using a sequential design, which showed a negative result.[1] 1. Fan HW, Marcopito LF, Cardoso JLC, et al. Sequential randomised and double blind trial of promethazine prophylaxis against early anaphylactic reactions to antivenom for bothrops snake bites. Brit Med J 1999; 318: 1451-53. Competing interests: None
Re: Re: There is a trial of promethazine 16 July 2009
Doerthe A Andreae, resident pediatrics St. Josefskrankenhaus, 79104 Freiburg, Germany, Michael H Andreae Send response to journal: Re: Re: Re: There is a trial of promethazine	Dear Dr. Nanivadekar, Thank you for your interest in our article and for alerting us to this study by Fan et al. This is a RCT on prophylaxis with intramuscular antihistamines prior to the clinical presentation of anaphylaxis in patients receiving antivenom therapy (but not on treatment after the development of allergic symptoms). You may counter that if antihistamines do not help to prevent, how will they help to treat anaphylaxis? Fair point, but strictly speaking, this conclusion cannot be made based on this study. It however underlines the potential for a trial in this patient group with a high incidence of allergic reactions. We would be happy to collaborate and support such a venture. Thank you again for your interest in our article. Yours Sincerely, Doerthe Adriana Andreae, MD & Michael H Andreae, MD Competing interests: None declared
What primary outcome for an antihistamine trial 3 August 2009
Simon G A Brown, Professor, Emergency Medicine Royal Perth Hospital, University of Western Australia, Perth, WA 6000, Australia Send response to journal: Re: What primary outcome for an antihistamine trial	Thank you for this review. I was interested to note a recommendation for future research that trials should use a primary outcome of "whether antihistamines result in reduced mortality". Given that death from anaphylaxis is rare, and that >50% of anaphylaxis deaths occur prior to reaching emergency medical care, I do not think this outcome will be useful. Perhaps we should first establish, using prospective observational studies in both hospital and community settings, what the clinical outcomes are with a simple protocol of supportive care including adrenaline and fluid resuscitation. The results of such studies may well remove the need for a clinical trial of antihistamines. Alternatively, they may suggest alternate, clinically relevant primary outcomes for a placebo-controlled trial of antihistamines, for example the incidence of side effects and/or the incidence of delayed phase ("biphasic") reactions. Competing interests: None declared