Evaluation of a low-dose oral contraceptive pill for primary dysmenorrhea: a placebo-controlled, double-blind, randomized trial.

Objective: To evaluate the efficacy and safety of low-dose oral contraceptives (IKH-01; 0.035 mg ethinyl estradiol and 1 mg norethisterone) for patients with primary dysmenorrhea.

Design: Placebo-controlled, double-blind, randomized trial.

Setting: Clinical trial sites in Japan.

Patient(s): One hundred fifteen patients with primary dysmenorrhea.

Intervention(s): Patients randomly assigned to receive IKH-01 or placebo for four cycles.

Main Outcome Measure(s): Total dysmenorrhea score, verbal rating scale defining pain according to limited ability to work and need for analgesics, and visual analog scale (VAS).

Result(s): Reduction in total dysmenorrhea score and VAS before and after treatment was significantly higher in the IKH-01 group than in the placebo group. Total dysmenorrhea score and VAS in the IKH-01 group significantly decreased from cycles 2 to 5. Overall incidence of adverse events was significantly higher in the IKH-01 group. Incidence decreased over time in the IKH-01 group; it was invariable in the placebo group. No serious adverse events occurred.

Conclusion(s): IKH-01 could be used as a single agent or in combination with analgesics for treatment of primary dysmenorrhea.