I used accutane maybe 10 years ago, although I wasn’t training at the time, so this will just be an extrapolation of how I felt. The side effect list will terrify you reading it all, because nearly every serious side effect possible is listed there.
The thing that got me quite bad, was it affected my mood. I was definitely depressed a bit, my energy levels were therefore very low, and would have certainly effected my desire to train. Just something to watch out for, and just realize you need to be prepared to give yourself some grace if you don’t feel like you want to train. Your skin will likely be verrrry dry sometimes, so just watch out for any irritation that might occur. Just like with anything else, cycling isn’t the whole world, the course of treatment is like 5 months if I remember right, so even if you have to cut back on your cycling, you will come out the other side. And hopefully with less acne! In the end though, listen to your doctors, if they tell you to cut back on training to avoid Rhabdo, they probably know what they are talking about. It’s better to not have permanently damaged kidneys , which the drug is already hard on.
As a side note, it basically cured my acne, and 10 years on, I rarely have any flareups.