I've taken generic allegra a couple of hours ago. is it safe to take theraflu severe cold and cough nighttime now?

Yes, is safe but I prefer to use single medicines instead of combinations that are in the many combinations. For example, if you want a pain reliever get Tylenol, or if you want a decongestant use phenylephrine or better Afrin for 2- 3 days is ok. If you have allergies and nasal congestion, use fluticasone or Flonase, if you need cough suppressant use dextromethorphan. If you are very sick see MD