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.
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