Drugs online research references
Pharm Res. 2001 May;18(5):694-701.
Lipophilicity behaviour of the Zwitterionic antihistamine cetirizine in phosphatidylcholine liposomes/water systems.
Plember van Balen G, Caron G, Ermondi G, Pagliara A, Grandi T, Bouchard G, Fruttero R, Carrupt PA, Testa B.
Institut de Chimie Therapeutique, Section de Pharmacie, Universite de Lausanne, Switzerland.
PURPOSE: The partitioning of cetirizine in a phosphatidylcholine liposomes/water system was compared with that of hydroxyzine and acrivastine to gain insight into the mechanisms of interaction of its various electrical species with membranes. METHODS: The lipophilicity profiles of the compounds were obtained from equilibrium dialysis and potentiometry, and compared with changes in NMR relaxation rates. RESULTS: The neutral form of hydroxyzine interacted mainly via hydrophobic interactions with the bilayer lipid core of the membrane, whereas for the cationic form both hydrophobic and electrostatic interactions were involved. Zwitterionic and anionic cetirizine were less lipophilic than its cation, which behaved like the corresponding species of hydroxyzine. Zwitterionic cetirizine interacted more by weak electrostatic interactions with the polar headgroups of phospholipids than by hydrophobic interactions with the membrane interior. The lipophilicity of its anion reflected the balance of repulsive electrostatic interactions between the carboxylate and phosphate groups and the hydrophobic interactions with the lipid core. CONCLUSION: The study confirms that various mechanisms influence the interaction of solutes with liposomes. Combining experimental techniques and using suitable reference compounds proves useful.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11465428&dopt=Abstract
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Am J Manag Care. 2001 Oct;7(15 Suppl):S459-68.
The costs of nonsedating antihistamine therapy for allergic rhinitis in managed care: an updated analysis.
Liao E, Leahy M, Cummins G.
PharMetrics, Inc, 150 Coolidge Avenue, Watertown, MA 02471, USA.
OBJECTIVE: To update a prior study evaluating the use and costs of new-generation antihistamines for the treatment of allergic rhinitis in a managed care population. STUDY DESIGN: A retrospective database review of rhinitis-related medical and pharmacy-related claims during a treatment period of 12 months. METHODS: Patients who had been diagnosed as having allergic rhinitis and had at least 1 prescription claim were identified from a database containing patient-level medical and pharmaceutical claims. The treatment patterns for patients meeting study criteria were documented for a 12-month period to describe how nonsedating antihistamines are being used in allergic rhinitis, and to assess the associated costs of various medications. Subanalyses of patients categorized by comorbidity status were also performed. RESULTS: A total of 105,696 patients were included in this updated analysis, covering calendar year 1999. Nonsedating antihistamines were used by 68% of the sample, with loratadine and fexofenadine being the most commonly prescribed agents. The mean annual rhinitis-specific charge for fexofenadine-treated patients was $409 (standard deviation [SD] 727), which was significantly lower compared with charges for loratadine-treated patients, $424 (SD 740), P = .0144, or cetirizine-treated patients, $444 (SD 625), P < .0001. This trend was also observed in comparisons of patient subgroups. CONCLUSIONS: Consistent with our prior study, loratadine and cetirizine were generally associated with significantly higher treatment charges than fexofenadine. This result was observed across different stratifications of patients, including those with comorbid respiratory illness, concomitant use of nasal steroids, and asthma and/or sinusitis. These results provide further useful insights into the differential costs associated with the use of nonsedating antihistamines for allergic rhinitis treatment.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11680261&dopt=Abstract
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psychology.unimaas.nl
The most pronounced side effect of antiallergic histaminergic drugs (H1 antagonists) is sedation. These effects have been linked with the effects of histaminergic drugs on central H1 receptors. In the present study, we investigated the dose-response relationship of different antihistamines on the performance in a reaction-time task that has been developed for rats. The dose-response relationship of diphenhydramine, cetirizine and terfenadine were examined for the various behavioural measures in this task (i.e., reaction time, motor time, premature responses and number of trials completed). In addition, the effects of scopolamine were assessed to evaluate the cholinergic profile in this task. Diphenhydramine did not reliably affect the reaction time, but increased the motor time and the proportion of premature responses, and decreased the number of trials completed in a session. A low dose of cetirizine decreased the reaction time, whereas an increase in reaction time was found for the high dose. The motor time was increased after both doses of cetirizine. Terfenadine did not affect the responding of rats in the reaction-time task at the doses tested. The effects of scopolamine were very similar to those of diphenhydramine. The reaction-time task used in this study was able to dissociate different types of antihistamines on aspects of psychomotor function, which were likely to be related to central muscarinic or H1 antagonism. These findings suggest that the reaction-time task may be a sensitive tool for assessing effects of drugs on psychomotor function.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11701216&dopt=Abstract
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