Related Experiment Video
Updated: Aug 19, 2026

Investigating the Effects of Antipsychotics and Schizotypy on the N400 Using Event-Related Potentials and Semantic Categorization
Published on: November 19, 2014
Central nervous system effects of antihistamines on evoked potentials
1Department of Neurology, Medical College of Georgia, Augusta.
Abstract:
Sedation is the most common side effect of antihistamine therapy. As with many behavioral constructs, attempts at quantification are difficult, and consequently, subjective reports of antihistamine sedation are frequently relied upon. Evoked potential activity is one method to quantitate the brain's response to subtle cognitive change. Evoked potentials are characteristic shifts in the brain's electrical activity that are obtained by time-locking the ongoing EEG to a stimulus over repeated trials. A late positive component of the evoked potential (P3) has been related to various psychologic properties including expectation, selective attention, and information processing speed. Because of this relationship, we employed the latency of the P3 evoked potential to measure the cognitive effects of chlorpheniramine and terfenadine. In healthy young subjects, we observed that terfenadine produces significantly less cognitive slowing of the P3 potential than chlorpheniramine. This finding supports the subjective findings of reduced sedative side effects of terfenadine.
More Related Videos
Related Concept Videos
Indirect-Acting Cholinergic Agonists: Pharmacological Actions
At the neuromuscular junction, these agents work by inhibiting the breakdown of acetylcholine, allowing it to remain bound to the receptor and bind to nearby receptors. This process leads to repetitive firing of the endplate, causing muscle...
Cholinergic Antagonists: Pharmacological Actions
Gastrointestinal Effects: Antimuscarinics reduce gut contractions, increase gastric emptying, and slow intestinal transit. They partly inhibit gastric acid secretion...
Local Anesthetics: Adverse Effects
Once absorbed into the systemic circulation, local anesthetics can affect the organs that depend on the functioning of sodium...
CNS Depressants: Barbiturates and Benzodiazepines
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Upper Respiratory Drugs: First and Second-Generation Antihistamines
Histamine binds to specific receptor sites, known as H1 receptors, on tissue cells, triggering inflammation and swelling. Antihistamines combat these effects by competing with histamine for these receptor sites. By...

