Evening primrose oil (Efamol) in the treatment of Raynaud's phenomenon: a double blind study

Belch JJ

Published in Thrombosis and Haemostasis

Methodology

Double-blind placebo-controlled trial of evening primrose oil over 8 weeks in patients with Raynaud's phenomenon, with attack diaries plus objective measures of digital blood flow and cold challenge.

Key Findings

In 21 patients with Raynaud's phenomenon, evening primrose oil (Efamol) for 8 weeks reduced the frequency and severity of attacks compared with placebo, although objective measures of digital blood flow and cold-challenge responses did not change significantly.

Conclusions

Evening primrose oil produced symptomatic improvement in Raynaud's attacks without demonstrable change in measured blood flow, a small early trial that has not been convincingly replicated.

Limitations

Very small 1980s trial with limited reporting of randomisation and allocation concealment, symptom diaries as primary endpoint, short 8-week duration, and discordance between symptomatic and objective vascular findings.