1. Reduction of the central nervous system adverse effects associated with antihistamines in the management of allergic disorders: Strategies and progress 
Fran M. Gengo, PharmD, FCP 
Journal of Allergy and Clinical Immunology 
Volume 98, Issue 6, Pages S319-S325 (December 1996)
DOI: /S (96)
Copyright © 1996 Mosby, Inc. Terms and Conditions

2. FIG. 1
Changes in recognition time. Magnitude of peak effect produced by dimenhydrinate on reaction time is in range of that expected with BAC in 0.08 gm/100 ml (g%) range. (Reproduced with permission from Manning C, Scandale L, Manning EJ, Gengo FM. Central nervous system effects of meclizine and dimenhydrinate: evidence of acute tolerance to antihistamines. J Clin Pharmacol 1992;32: )
Journal of Allergy and Clinical Immunology  , S319-S325DOI: ( /S (96) )
Copyright © 1996 Mosby, Inc. Terms and Conditions

3. FIG. 2
Relative potencies of hydroxyzine (top) and cetirizine (bottom) at six receptor-binding sites in rat brain membranes. Pharmacologic specificity of hydroxyzine is such that its activity at other neurotransmitter-receptor sites is as high as its activity at histamine-receptor sites in rat brain membranes. Data for voltage sensitive calcium channels (VS Ca2+ channel) are from binding assays with [3H]nitrendipine. Ligands and assay conditions are described by Snyders and Snowman.23 5HT-2 serotonin, 5-Hydroxytryptamine-2 serotonin. (Reproduced with permission from Snyders H, Snowman AM. Receptor effects of cetirizine. Ann Allergy 1987;59(Pt II):4-8.)
Journal of Allergy and Clinical Immunology  , S319-S325DOI: ( /S (96) )
Copyright © 1996 Mosby, Inc. Terms and Conditions

4. FIG. 2
Relative potencies of hydroxyzine (top) and cetirizine (bottom) at six receptor-binding sites in rat brain membranes. Pharmacologic specificity of hydroxyzine is such that its activity at other neurotransmitter-receptor sites is as high as its activity at histamine-receptor sites in rat brain membranes. Data for voltage sensitive calcium channels (VS Ca2+ channel) are from binding assays with [3H]nitrendipine. Ligands and assay conditions are described by Snyders and Snowman.23 5HT-2 serotonin, 5-Hydroxytryptamine-2 serotonin. (Reproduced with permission from Snyders H, Snowman AM. Receptor effects of cetirizine. Ann Allergy 1987;59(Pt II):4-8.)
Journal of Allergy and Clinical Immunology  , S319-S325DOI: ( /S (96) )
Copyright © 1996 Mosby, Inc. Terms and Conditions

5. FIG. 3
Effects of cetirizine and diphenhydramine on reaction time. In double-blind, five-way crossover study, 15 male volunteers, mean age 23.8 years, ingested placebo; cetirizine 5, 10, or 20 mg; or diphenhydramine 50 mg. Subjective measurements of drowsiness and objective measurements of mental performance were made 2 hours after dosing. During accident avoidance in automobile-driving simulation, diphenhydramine 50 mg slowed reaction time significantly compared with placebo and with cetirizine, 5, 10, or 20 mg. (Reproduced with permission from Gengo FM, Gabos C, Mechtler L. Ann Allergy 1990;64:520.)
Journal of Allergy and Clinical Immunology  , S319-S325DOI: ( /S (96) )
Copyright © 1996 Mosby, Inc. Terms and Conditions