In a study by Akin et al,32 investigating the effectiveness
of heat patches and acetaminophen in relieving dysmenorrhea,
the pain severity during the first day of menstruation
was evaluated through 8 hours. This study found that
pain levels in the heat-patch group significantly decreased
compared to those in the acetaminophen group, after 1.5
hours of treatment, and that a significant difference existed
between the groups regarding the pain levels at the 3rd, 4th,
5th, and 6th hours of the intervention (P ! .05).