Sorry, Androcur is not available in the US.
Yes, there are many alternatives to Spironolactone as an Androgen Blocker. Most of these drugs are used for prostate cancer and they all have side effects. In my opinion, Spironolactone is the safest Androgen Blocker today with most people not having any problem with their potassium levels.
One thing really bothers me, if your new doctor wants you to find alternatives to your HRT, that doctor is not doing their job. You are not expected to be an expert in HRT. The prescriber is the expert. If your new doctor doesn't have that knowledge base, then ask for a doctor who does, such as an endocrinologist, or better yet, a new primary care doctor who knows what they are doing.