I am not sure what are the exact medications that you are taking because you have not mentioned it. But it is clear from your question that only with one dose your nose started bleeding. It is unlikely that it is due to the medicine. If you have nose bleeds apply ice on your nose as well as pinch your nose. If the bleeding continues and there isnt any particular reason for that then it is better if you visit your ENT specialist
to make sure there isnt anything grossly wrong.
I hope you found my response to be helpful and informative. If you have any additional concerns I would be happy to address them.