Yes, there are lots of chemicals in cigarettes (1000s) and tar/benzene/formaldehyde are some of them with 40 carcinogens. So it is time you realised stopping smoking
is the best way out.
Sulphur and nitrates are definitely added but unsure in what proportions (will vary with brand)
No tests can predict whether one will develop SJS to a drug, but if it is sulphur-related in your case, please steer clear of such drugs.