Do antihistamines have an effect on neurotransmitters?

Yes, antihistamines can affect neurotransmitters, particularly by blocking the action of histamine at H1 receptors in the brain. This can lead to sedative effects, as histamine is involved in promoting wakefulness and alertness. Additionally, some antihistamines may influence other neurotransmitter systems, such as acetylcholine, which can contribute to side effects like dry mouth and drowsiness. Overall, their primary role is to alleviate allergic symptoms by counteracting histamine's effects.