The best replacement for drowsiness is fatigue.

The best alternatives to drowsiness are rated as following:
★★★★★  fatigue
★★★  dizziness
★★★  sleepiness
★  drowsiness
★  somnolence

Your alternative for drowsiness is not listed? Suggest!
Speaking about drowsiness, one probably shouldn't forget about antihistamines.

Other search terms related to drowsiness and their ratings are:
★★★★★ antihistamines
★ anti depressants
You have in mind a companion for drowsiness and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of drowsiness in all years. Click on graph for more.
drowsiness
fatigue
dizziness