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Three Part Question

In [adults presenting to the emergency department with an acute porphyric attack requiring rapid sequence induction] is [suxamethonium safe and effective] at [inducing muscle relaxation]?

Clinical Scenario

A 24 year old female with acute intermittent porphyria presents to the emergency department with abdominal pain, paresis and difficulty breathing after a night of heavy drinking. You fear progression to respiratory paralysis so decide to perform rapid sequence induction. You wonder if the use of suxamethonium as a muscle relaxant may exacerbate the attack.

Search Strategy

Medline 1966-06/06, Embase 1980-06/06 and Cinahl 1982-06/06 via the Ovid interface
Medline:[suxamethonium .mp. or exp succinylcholine/ or muscle relaxant.mp. or exp muscle relaxants, central/] AND [exp porphyrias/ or porphyria.mp. or porphyrias.mp. or AIP.mp.] LIMITS humans and english
Embase and Cinahl:[suxamethonium .mp. or exp succinylcholine/ or muscle relaxant.mp. or exp muscle relaxants, central/] AND [exp porphyria/ or porphyria.mp. or porphyrias.mp. or AIP.mp.] LIMITS humans and english
Cochrane: porphyria

Search Outcome

Medline: 17 results-1 relevant
Embase:3 results-1 additional relevant
Cinahl: 0 results
Cochrane:32 results- 0 relevant
A manual search of the results of my other BETs on acute porphyria revealed 1 additional paper

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Mustajoki P, Heinonen J 1980 Finland	37 patients with acute porphyria who received various anaesthetics (including thiopenal, ketamine, hexobarbitol) on 62 occasions. There were 32 exposures to succinylcholine. 14 patients with acute porphyria who recieved anaesthetics during an acute attack on 16 occasions. 6 exposures to succinylcholine.	Retrospective case series. Data from hospital records and questionaires. Level 3 evidence.	Number of patients with symptoms suggestive of an acute attack (in patients not having an acute attack)	No acutes attack occured.	No data on urinary PBG Potentially porphyrinogenic anesthetics used alongside succinylcholine.
			Exacerbation of the attack (in patients who were having an acute attack)	Exacerbation of acute attack in 4 cases with death in 1 case-however these patients all recieved thiopental, known to exacerbate porphyria
Dover SB, Plenderleith, Moore MR, Mc Coll KEL 1994 UK	25 patients with acute porphyria undergoing 38 surgical operations under general anaesthetic.30 operations were performed in 20 patients with AIP,7 in 4 patients with variegate porphyria and one in a patient with hereditary coproporphyria. 19 patients were known to have porphyria and 8 were undiagnosed at the time of surgery.Suxamethonium was given on 10 occasions to the patients previously diagnosed with porphyria.	Combined retrospective and prospective case study. 5 patients (known to have porphyria) had ALA and PBJ measured perioperatively for variable durations between days -2 and 7 and any symptoms of an acute attack were noted in all patients.	Symptoms suggestive of an acute attack	None of the patients known to have porphyria at the time of surgery had symptoms of an acute attack but of the patients with undiagnosed porphyria 7 had crisis, 2 resulting in death (not reported if suxamethonium had been used in any of these cases).	The data was incomplete-only 5 patients had urinary PBG and ALA measured perioperatively and for variable amounts of time.There was no mention of the drugs each of these 5 patients recieved. The basic data was not adequately described-no exact figures were given-only a roughly drawn diagram and terms such as 'a transient rise (in PBG)' and '(PBG) nearly doubled' used when describing the perioperative changes in PBG and ALA. No statistical analysis was performed. Numbers do not add up. It says that the study was conducted in 25 patients but later says that 19 patients had diagnosed porphyria and 8 had undiagnosed porphyria at the time of the operation.
			Urinary PBG excretion	3 of the 5 patients with their PBG monitored had a 'transient rise' in ABG.
			Urinary ALA excretion	2 of the 5 patients with their ALA monitored showed increased ALA excretion-one more than 4 times the upper limit of normal and one within normal limits
Meissner, P.N., Harrison GG, Hift RJ. 1991 South Africa	13 patients with variegate porphyria requring general anaesthesia for elective surgery. Suxamethonium or atracurium were used for muscle relaxation. (All were given IV propofol.Other drugs recieved were fentanyl, alfentil and morphine were also used.)	Case series. Level 3 evidence.	Number of patients with symptoms suggestive of an acute attack after administration of propofol	No patients suffered symptoms suggestive of an acute attack of porphyria	Case series Level 3
			Urinary ALA, PBG measured on day before operation-day 0, day 1, day 3 and day 5	No significant increase in concentrations of ALA and PBG

Comment(s)

Suxamethonium was used safely as a muscle relaxant in over 42 patients with acute porphyria and there was no increase in porphyrin precursors where this was measured. Drug databases listing safe and unsafe drugs are a useful reference in the treatment of acute porphyria (Level 4 evidence). The information they provide is based on published case reports, previously published drug lists, theoretical considerations and clinical experience. Suxamethonium has been classified as safe in drug lists produced by the European Porphyria Initiative, The Welsh Medicines Information Centre University of Cape Town Porphyria Serviceand The Norwegian Porphyria Centre (NAPOS) [1-4].

Clinical Bottom Line

Suxamethonium is safe to use in patients with an acute porphyria.

References

1. Mustajoki P, Heinonen J General Anesthesia in Inducible Porphyrias Anesthesiology 1980:53;15-20
2. Dover SB, Plenderleith, Moore MR, Mc Coll KEL Safety of general anaesthesia and surgery in acute hepatic porphyria Gut 1994;35:1112-1115
3. Meissner, P.N., Harrison GG, Hift RJ. Propofol as an IV anaesthetic induction agent in variegate porphyria The British Journal of Anaesthesia 1991:66;60-65
4. The norweigan porphria centre Drug database for acute porphyria
5. The welsh medicines information centre Drugs that are considered safe for use in the acute porphyrias
6. University of Cape Town porphyria service Drug safety;alphabetical listing
7. European Porphyria Initative. Drugs and porphyria