The cognitive effects of so-called "non-drowsy" antihistamines are typically unknown to the general public because they're usually taken in low doses over the short term.
However, on their doctor's advice, those with chronic urticaria are often on an extended high-dose treatment. It's important to note that almost all antihistamines can affect cognitive function since they cross the brain barrier. Problems with memory, attention, reaction times, decision-making, and psychomotor coordination have all been reported.
Most non-drowsy antihistamines are linked to problems with memory, attention, reaction times, decision-making, psychomotor coordination, etc.
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Always discuss any medical concerns with your doctor.