You can google Primolut N and up will come several listings that give its consumer information. For example:
http://72.14.253.104/search?q=cache:GNWTjZ2HuuAJ:www.medsafe.govt.nz/Consumers/CMI/p/primolut-n.htm+primolut+N.&hl=en&ct=clnk&cd=3&gl=us
If you right-click the link I just listed, it will tell you about side effects and so forth. It sounds like deep vein thrombosis is the main concern, as with many similar medicines.