Antihistamines cognitive effects

Tharion, WJ, McMenemy, DJ and Rauch, TM (1994) Antihistamine effects on the central nervous system, cognitive performance and subjective states. Neurophsychobiol. 29 97-104. 

Gandon JM, Allain H. Lack of effect of single and repeated doses of levocetirizine, a new antihistamine drug, on cognitive and psychomotor functions in healthy volunteers. Br J din Pharmacol 2002 54(l) 51-8. 

Adverse reactions with antihistamines are the result of multiple mechanisms (see Figure 13-3). Muscarinic, a-adrenergic, and serotonin receptor blockade may result in mydriasis, dry mouth and eyes, urinary retention, constipation, and dizziness in first-generation antihistamines. When the neurotransmitter effect of histamine is interrupted, various CNS adverse reactions may occur. These side effects include increased sedation, decreased cognitive function, decreased psychomotor function, and headache. 

Kay GG, Harris AG. Loratadine a non-sedating antihistamine. Review of its effects on cognition, psychomotor performance, mood and sedation. Clin Exp Allergy 1999 29(Suppl 3) 147-50. 

I Sedation and Cognition. Sedation must be recognized as an antipsychotic side effect and not as an indication of therapeutic effect. It occurs more frequently with antipsychotics with antihistaminic properties. Chlorpromazine, thioridazine, mesoridazine, clozapine, olanzapine, and quetiapine are most frequently implicated. Administration of most or all of the daily dosage at bedtime (depending on the drug half-life) can decrease daytime sedation and in some patients eliminate the need for hypnotic agents. Sedation occurs early in treatment... 

First-generation HI antihistamines commonly result in sedation and impaired cognitive and psychomotor performance due to decreased CNS neurotransmission. Some first-generation HI antihistamines have been associated with accidental or intentional overdose and have been drugs of abuse. Second-generation HI antihistamines are less sedating and have few toxic effects in the setting of overdose. The effects on muscarinic receptors... 

Kay, G.G. Harris, A.G. (1999). Loratadine A Non-Sedating Antihistamine. Review of its Effects on Cognition, Psychomotor Performance, Mood and Sedation. Clinical Experimental Allergy, Vol. 29, No. Suppl 3, (July 1999), pp. 147-150, ISSN 0954-7894... 

Kay GG, 2000. The effects of antihistamines on cognition and performance. / Allergy Clin Immunol. 105 S622. 

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