Comparison of Oral Mefenamic Acid with Transdermal Glyceryl Trinitrate in the Management of Primary Dysmenorrhea

Treatment of dysmenorrhea in women is aimed to bring them to their normal condition. In the present study, the effect of mefenamic acid, a non-steroidal anti-inflammatory drug, was compared with that of transdermal glyceryl trinitrate (GTN) as a tocolytic drug in the management of primary dysmenorrhea.
A total of 160 nulliparous women aged 18-30 years with primary dysmenorrhea were included in this single blind, clinical trial, which was carried out from 2014 to 2015. The patients were randomly divided into two equal groups. At the beginning of menstruation cycle, the patients in group A received 500 mg oral mefenamic acid, followed by 250 mg mefenamic acid every 6 hours. The patients in group B initially were administered 2.5 mg transdermal glyceryl trinitrate 0.2% every 12 hours to the abdominal skin under the umbilical cord. Treatment was continued for up to 48 hours and repeated for three cycles. Pain scores were assessed by Numerical Rating Scale (NRS) every 4 hours. Adverse effects such as headache and gastrointestinal disorders were recorded. The decrease of pain scale was the primary outcome and adverse effects were the secondary outcome.
The mean pain severity score in in the first 24-hours in mefenamic acid group was lower than that of the glyceryl trinitrate group (p=0.01). On the second day, the mean pain severity scores were not significantly different between the two groups. The mean pain severity scores in the second day of second cycle (p The analgesic effects of oral mefenamic acid were better than transdermal glyceryl trinitrate in the management of primary dysmenorrhea. The adverse effects of these two drugs were not significantly different, but the type of complications was different in both groups.