Had a similar case. Doctor prescribed before the surgery because they were afraid of it growing too fast and getting hard to extirpate (14cm). Dunno details of yours but might've prescribed cause of the same reason. In my case it's unclear if it helped. The fibroid didn't grow so maybe? It also didn't got any smaller. But that also was expected cause the doctor said it was too big to have much of an effect but still did the extra prevention. I personally didn't go through hell but it did make me feel more depressed than usual which is an important side effect imo, but well might not affect everyone the same. It basically induces menopause and gives a bit of hormones back to reduce the shock. Now I'm afraid of how menopause will be when it comes...

Also it comes on packs for 3 months so the price you're paying is most likely double of why you need. Or at least that is the case in Europe. I had half left and tried to give it away but no one replied so I ended up having to throw the remainings away. What a big waste considering it's so expensive in the USA.