How Do First Generation Antihistamines Affect Alertness?
It is of common knowledge that taking antihistamines can make people very tired and unable to focus during the day. This is due to the fact that these drugs, like Benadryl, can cross the blood-brain barrier and affect the processes of many neurotransmitters due to the drug’s lack of specificty. First generation antihistamines depress the central nervous system proceses causing sedation. In a randomized study by JM Wieler et al, “a 50mg dose of diphenhydramine (Benadryl) impared driving performance to a greater extent than alcohol; the alcohol dose produced an estimated blood alcohol concentration of 0.1 percent.
