Surname ปฐมฤทธิ์ (ปฐมฤทธิ์ 
, Pathomrit 
) , around the world, is a very rare last name. The cognomen ปฐมฤทธิ์ is characteristic of Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Much less frequently, ปฐมฤทธิ์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| ปฐมฤทธิ์ | Thailand |
| Pathomrit | United States, Thailand |