Ogawa 2002.

Methods	Double blind, randomised controlled trial
Participants	57 adults (aged 20 to 68 years), 39 male and 18 female, randomly assigned to 2 different treatment groups
Interventions	Group 1: the patients in the PGE1 group received a continuous infusion containing 60 mcg PGE1 and 100 mg hydrocortisone Group 2: the placebo group were treated with a continuous infusion of an inactive placebo and 100 mg hydrocortisone
Outcomes	1. Complete recovery ‐ all 5 frequencies of final audio </= 20 dB 2. Remarkable improvement: PTA improvement > 30 dB 3. Improvement: PTA improvement is 10 to 30 dB 4. No change or deterioration: PTA improvement is < 10 dB No significant differences were observed in the improvements of pure tone average and subjective symptoms between PGE1 and placebo groups, however significant improvement was noted in higher frequencies and tinnitus (44% versus 13%)
Notes	No adverse effects were documented in the study