The idea that allergy pills 'stop working' after months of daily use isn't well supported by the evidence — but the FDA has flagged a real, different reaction to watch for when you quit.

It's not just distraction. Cortisol bottoms out at night while histamine activity rises, and mosquitoes themselves are built to hunt hardest at dusk and dawn.

The idea that Zyrtec or Claritin "stops working" after enough years is mostly folklore. The medicine that genuinely does lose its effect is the decongestant spray sitting next to it.