High dose eicosapentaenoic acid ethyl ester: effects on lipids and neutrophil leukotriene production in normal volunteers.

1. A 93% pure ethyl ester of eicosapentaenoic acid was investigated for tolerability and biochemical effects on neutrophil leukotriene synthesis and plasma lipoproteins when given in high dose. Six healthy volunteers received 6 g eicosapentaenoic acid ethyl ester daily for 6 weeks, followed by a 4 week wash-out and then 18 g daily for 6 weeks. 2. There was inhibition of neutrophil leukotriene B4 and 5-hydroxyeicosatetraenoic acid synthesis, with no significant differences between low and high dose. 3. There was a dose dependent increase in leukotriene B5 and 5-hydroxyeicosatetraenoic acid acid synthesis. 4. Plasma triglycerides were reduced maximally on 6 g daily, with no greater suppression at 18 g daily. 5. Plasma cholesterol was only suppressed significantly at 18 g daily. 6. The 6 g daily dose was well tolerated but the 18 g daily dose produced diarrhoea and steatorrhoea.