Anaesthetic doses will render you either unconscious or too disoriented to take the SN or a 2nd drink.
If you take it after the SN and a large enough dose, it would anesthetize you. FDCK will cause hallucinations and often dizziness in moderate to large doses, which can be uncomfortable for many people in itself, especially when you are dying; it may increase SI.
I would personally recommend a different painkiller, or a blackout dose of benzodiazepines.
Any additional drugs will increase your chances of vomiting.