Do aircomb (montelukast&desloratadine) and rupafin (rupatadine) meds contain promethazine? if so, how long will it take to get them out of my system?

No: promethazine is not that commonly used anymore and it is not present in any of the medication you are taking. As a rule of thumb, it will likely take about a week for a medication to clear completely some long-acting drug may take longer) but 1/2 of the drugs is usually gone in less than 24 hours. However each person has a different drug breakdown (catabolism) profile as would be each drug.