Can Diprivan be given to patients with an egg allergy since the formulation of "Diprivan" contains 1.2% egg yolk phospholipid?

The soybean oil which Zeneca uses in 'Diprivan' undergoes a stringent purification process whereby all protein within the oil is removed. Patients who are allergic to eggs are generally allergic to egg protein or albumin, not lecithin (the egg phosphatides which are present in the ‘Diprivan’ emulsion). A thorough search of the literature has revealed no evidence that lecithin is allergenic, or that it could act as a hapten, thus inducing allergenicity. The literature indicates that it is the glycoproteins found in food that are generally implicated as the allergenic component (Sampson and Cook, 1990).

The glycoproteins are characteristically water soluble, largely heat resistant and acid-stable, and commonly in the molecular weight range14-60 KDa. Sampson and Cook (1990) refer to four other papers where the specific allergenic components of egg and cow's milk have been isolated and characterised. They concluded that patients clinically allergic to egg and / or cows milk possess IgE and IgG antibodies to protein fractions in egg and cow's milk.

There is a recent case report by Bassett et. al. (1994) of an adverse allergic reaction to propofol in a patient with egg hypersensitivity. The authors state that 'propofol emulsion contains egg lecithin, a phosphatidylcholine found in egg yolk' and suggest that 'a history of egg allergy may have to be considered prior to administration of propofol'. This conclusion seems at odds with the studies quoted above. It seems more likely that the allergy in this case is due to either propofol or Intralipid, even though the incidence of allergy to either agent is very low. The incidence for propofol has been estimated to be 1 in 15 000 anaesthetics, irrespective of the mechanism involved and in 1 in 45 000 for immune reactions (Laxenaire et. al., 1992). The incidence with Intralipid is probably even lower. There have been very occasional reports of hypersensitivity following Intralipid eg., Kamath et.al., (1981) and Hiyama et. al. (1989). Hiyama et. al. (1989) using the RAST test demonstrated that an allergic response observed after Intralipid was probably due to soybean protein.

In conclusion, it does seem very likely that people who are allergic to eggs are allergic to the protein component. This could explain why 'Diprivan' is only very rarely a problem since the egg component in the emulsion is phospholipid. However, it is always advisable to ascertain the exact allergen in each individual case before deciding causality.

References

Bassett,C.W., Talusan-Canlas,E., Holtzin,L., Kumar,S., Chiaramonte,L.T.
An adverse reaction to propofol in a patient with egg hypersensitivity
Journal of Allergy and Clinical Immunology, 1994* 93 (1) Part 2: 242 Abs 476

Hiyama,D.T., Griggs,B., Mittman,R.J., et. al.
Hypersensitivity following lipid emulsion infusion in an adult patient
Journal of Parenteral and Enteral Nutrition, 1989, 13 (3) 318 - 320

Kamath,K.R., Berry,A.
Acute hypersensitivity reaction to Intralipid
New Engalnd Journal of Medicine, 1981, Feb 5* 360

Laxenaire,M.C., Maten-Bermejo,E., Moneret-Vautrin,D.A., Gueant,J.L.
Life-threatening anaphylactoid reactions to propofol ('Diprivan')
Anesthesiology, 1992, 77: 275 - 280

Sampson,H., Cook,S.K.
Food allergy and the potential allergenicity-antigenicity of microparticulated egg and cow's milk proteins
Journal of the Amercian College of Nutrition, 1990* 9 (4)* 410 – 417