What's inside salmeterol in prescription advair which could kill a few asthmatics?

See below. It's not the medication that has been linked to death itself. It's when this medication is used, all the beta receptors are blocked by the salmeterol thus the short acting beta agonist - your rescue inhaler - won't bind thus won't work as well or at all. this was primary seen in the black population.
Med... Salmeterol is a long acting beta-agonist, a type of bronchodilator (like albuterol!). A study found that use of long-acting beta-agonists was dangerous in some, but not all asthmatics. This is a prescription med so a doctor needs to prescribe it and monitor the patient carefully. This is another reason not to take someone else's medicine!
Good question. Studies have shown that salmeterol, used by itself, is not an effective treatment for asthma in some patient populations. The salmeterol does not kill anyone directly; rather, it is simply not effective enough to sufficiently treat the asthma and patients occassionally die of severe asthma attacks or related problems.