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Three Part Question

In [patients with anaphylaxis] is [intramuscular adrenaline better than intravenous adrenaline] at [treating the anaphylaxis and avoiding toxicity]?

Clinical Scenario

A 23 year American holiday maker arrives to emergency department after having Indian curry with nuts. He has severe allergic reaction and breathing difficulty. He has no cardiac conditions. You are about to give intravenous adrenaline, and your colleague arrives and tells you 'it's too risky', just give it intramuscular. You wonder whether there is any evidence.

Search Strategy

Medline 1966- 03/2007 using ovid interface
([exp adrenaline or epinephrine.mp. or adrenali*.mp. or epinephri*.mp] and [route or intramuscular or intravenous] and [hypersensitivity or anaphyla$.mp. or allerg$.mp.])
LIMIT to humans and English language
Cochrane databases:
Adrenaline for the treatment of anaphylaxis with or without shock(Protocol) Cochrane database of systematic reviews 2006

Search Outcome

164 papers found.
2 were relevant to the question.
Cochrane review protocol and expert opinions are discussed in the comments section.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Shaver K J, Adams C, Weiss S J July 2006 Canada	Case report Allergy to penicillin, 29 year patient without any previous cardiac problem	Level 4	Epinephrine induced coronary spasm with raised Troponin I ; Dose of epinephrine used: 0.1 mg of 1:10000 diluted to 10 cc preloaded syringe	Intramuscular injection may be safer	Single case report Co-incidental AMI can not be excluded in a highly charged emotional situation
Brown SGA et al Sept 2003 Australia	21 healthy adults with diagnostic sting challenge	Prospective randomized double blind controlled trial	Titrated adrenaline infusion combined with volume resuscitation is effective treatment of anaphylaxis	1 patient required intramuscular adrenaline, intravenous infusion was titrated according to patient condition; 3 other patient s also had complications	Healthy volunteers Several other drugs including Atropine and steroids were used Coronary vasospasm in one occurred in one patient, the cause of which can not be proved

Comment(s)

Adrenaline is an alpha- and beta-adrenergic agonist. It causes vasospasm and inotropic effect on the heart. Inappropriate dose or route of administration can cause more harm than beneficial effect. There have several case reports of epinephrine-inducing coronary vasospasm and arrhythmias. They all provide level four evidence hence only one of them is described in the table above. AMI due to adrenaline has responded well to nitroglycerine in all the reported cases, however in one case thrombolysis was done, but subsequent coronary catheterization was normal. Cochrane protocol has acknowledged that dose and route of adrenaline is largely based on extrapolation and assumption. Standard first line treatment in the form of epipen as intramuscular injection is widely upheld. In healthcare settings, the intramuscular &/or intravenous routes are preferred. The protocol suggests that mild to moderate reactions may improve without the use of adrenaline. In a letter to BMJ(2003), Gouglass J A and Professor O'Hehir has stated that intramuscular route is safer and has no cardiac toxicity to the best of their knowledge.

Clinical Bottom Line

Intramuscular injection is safer than intravenous adrenaline. Intramuscular adrenaline is recommended by the Resuscitation council of UK(2005).

References

1. Shaver K J, Adams C, Weiss S J Acute myocardial infarction after administration of low dose intravenous epinephrine for anaphylaxis Journal of the Canadian Association of Emergency Physicians Vol 8, Issue 4, Page 289-294
2. Brown S G A et al Insect sting anaphylaxis; prospective evaluation of treatment with intravenous adrenaline and volume resuscitation Emerg Med J 2004;21:149-154