You should discuss this with your doctor. You may get side effects, you may not. And you can die from ITP too, so if it's the only treatment they can offer you, it may be worth the risk. And the risk of death may not be as high in reality as you're finding on the internet. And those who die may have other reasons for being at increased risk. I don't know anything about you, or the severity of your ITP, or what treatments you've been on before, or this specific treatment, so the only person who can advise you is your doctor.