What could happen if i took 2 50mg benadryl (diphenhydramine) pills at the same time?

Grogginess: It's not unusual to need higher doses of antihistamines for itchy rashes such as hives or eczema; even, but because the drug crosses into the brain, central nervous system sedation (grogginess, drowsiness, sleepiness) occurs. Don't drive - your reaction times will be slowed. Avoid alcohol. May get dry mouth, and guys with enlarged prostates will find it harder to go.