From the Guidelines
Naproxen makes menstrual periods lighter by inhibiting prostaglandin production, which reduces uterine contractions and inflammation, resulting in decreased blood flow and lighter menstrual bleeding. This is based on the mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs) like naproxen, which block the enzyme cyclooxygenase (COX), reducing prostaglandin synthesis in the uterine lining 1. When taking naproxen, it is typically recommended to take 250-500mg every 8-12 hours as needed, and some doctors suggest starting 1-2 days before the period begins and continuing through the heaviest days of flow. Some key points to consider when using naproxen for menstrual bleeding include:
- Naproxen can be used to treat spotting or light bleeding, as well as heavy or prolonged bleeding, in users of certain contraceptive methods, such as the copper intrauterine device (Cu-IUD) or the implant 1
- The treatment may be repeated as needed, but it is essential to follow the recommended dosage and consult with a healthcare provider if symptoms persist or worsen
- Naproxen may have side effects, such as stomach irritation, so taking it with food is advisable
- Individuals with certain conditions, like stomach ulcers, kidney problems, or bleeding disorders, should avoid naproxen or use it only under medical supervision.
From the Research
Mechanism of Naproxen in Reducing Menstrual Bleeding
- Naproxen, a nonsteroidal anti-inflammatory drug (NSAID), has been shown to decrease prostaglandin secretion from cultured human endometrial stromal cells, which can lead to reduced uterine contractility and pain 2.
- The reduction in prostaglandin secretion is associated with decreased expression of cyclooxygenase-2 (COX-2) and increased expression of hydroxyprostaglandin dehydrogenase (HPDG) 2.
- Naproxen has also been found to reduce the volume of menstrual blood loss, although the evidence is very uncertain 3.
Effect of Naproxen on Menstrual Pain and Bleeding
- Naproxen has been shown to be effective in reducing menstrual pain, with 80% of patients with significant primary dysmenorrhea experiencing adequate relief 4.
- A study found that naproxen reduced the number of days of sick leave per two menstruations from 40 to 7, and decreased the number of hours of bed rest from 16.4 to 1.2 5.
- Naproxen has also been found to change the amount of bleeding in some women, with 12 women experiencing a change in bleeding amount and 3 women experiencing delayed bleeding 5.
Comparison with Other Treatments
- Naproxen has been compared to other treatments, such as acetaminophen, and has been found to be more effective in reducing menstrual pain 6.
- A review of interventions to prevent or treat heavy menstrual bleeding or pain associated with intrauterine device use found that naproxen may reduce pain, but the evidence is low-certainty 3.