Excitability may occur
Alcohol, sedatives and tranquilizers may increase drowsiness
Drowsiness may occur
So I'm not sure if this thing was just trying to cover all it's bases but the pill can either cause excitability or drowsiness. That's like the weather forecast saying that it may rain, snow, or be sunny just to make sure they are never wrong. That part I can sort of understand, maybe some crazy will try to sue them if they take the pill then get sleepy. Or someone who takes the pill before going to bed may blame them for not being able to sleep. Perhaps they should have included that the pill may have no impact whatsoever on one's energy, just in case someone has a false expectation.
The middle warning is what really confuses me. Tranquilizers may increase drowsiness. I would hope so, if not what's the point of the tranquilizer? But one minor detail... this is not a tranquilizer, it's an allergy pill.
Why not include in there that speeding may cause an accident, or studying will cause you to do well on a test. It seems like a waste of print space to include that taking a sedative, or tranquilizer 'may' make you drowsy.
So I have created my own list that should be printed on the back of every medicine, in case someone should not know these things:
Opening your eyes may cause you to see something.
Listening may cause you to learn something.
Never shutting up may cause you to lose friends.
Drinking water may cause you to not be thirsty.
Swimming may cause wetness.
Owning chickens may cause you to get eggs in the morning.
Owning a rooster may cause you to lose sleep in the morning.
Watching Twilight may cause drowsiness.
Watching Twilight may cause excitability.
Reading this list may cause you to waste moments of your life that you will never get back.