triprolidine and fexofenadine

Most of the modern non-sedating H1 receptor antagonists (antihistamines) penetrate the brain poorly, allowing the use of doses large enough to counteract allergic processes in peripheral tissues without important central effects. The antihistamines reviewed here are acrivastine, astemizole, cetirizine, ebastine, fexofenadine, loratadine, mizolastine, and terfenadine. However, these drugs are not entirely free from central effects, and there are at least quantitative differences between them. Although psychomotor and sleep studies in healthy subjects in the laboratory may predict that an antihistamine does not cause drowsiness, the safety margin can be narrow enough to cause a central sedating effect during actual treatment. This might result from a patient's individual sensitivity, disease-induced sedation, or drug dosages that are for various reasons relatively or absolutely larger (patient's weight, poor response, reduced drug clearance, interactions). Mild to even moderate sedation is not necessarily a major nuisance, particularly if stimulants need be added to the regimen (e.g. in perennial rhinitis). Furthermore, patients can adjust doses themselves if needed. Sedating antihistamines are not needed for long-term itching, because glucocorticoids are indicated and more effective. It is wise to restrict or avoid using antihistamines (astemizole, terfenadine) that can cause cardiac dysrhythmias, because even severe cardiotoxicity can occur in certain pharmacokinetic drug-drug interactions. Histamine H1 receptor antagonists (antihistamines) are used in the treatment of allergic disorders. The therapeutic effects of most of the older antihistamines were associated with sedating effects on the central nervous system (CNS) and antimuscarinic effects causing dry mouth and blurred vision. Non-specific "quinidine-like" or local anaesthetic actions often led to cardiotoxicity in animals and man. Although such adverse effects varied from drug to drug, there was some degree of sedation with all old antihistamines. Non-sedating antihistamines have become available during the past 15 years. Some of them also have antiserotonin or other actions that oppose allergic inflammation, and they are not entirely free from sedative effects either. In small to moderate "clinical" concentrations they are competitive H1 receptor antagonists, although large concentrations of some of them exert non-competitive blockade. Daytime drowsiness and weakness are seldom really important,

Topics: Astemizole; Benzimidazoles; Butyrophenones; Central Nervous System; Cetirizine; Drug Interactions; Heart; Histamine H1 Antagonists; Humans; Hypnotics and Sedatives; Loratadine; Piperidines; Potassium Channel Blockers; Terfenadine; Triprolidine

To investigate the frequency with which sedation was reported in post-marketing surveillance studies of four second generation antihistamines: loratadine, cetirizine, fexofenadine, and acrivastine.. Prescription-event monitoring studies.. Prescriptions were obtained for each cohort in the immediate post-marketing period.. Event data were obtained for a total of 43 363 patients.. Reporting of sedation or drowsiness.. The odds ratios (adjusted for age and sex) for the incidence of sedation were 0.63 (95% confidence interval 0.36 to 1.11; P=0.1) for fexofenadine; 2.79 (1.69 to 4.58; P<0.0001) for acrivastine, and 3.53 (2.07 to 5.42; P<0.0001) for cetirizine compared with loratadine. No increased risk of accident or injury was evident with any of the four drugs.. Although the risk of sedation was low with all four drugs, fexofenadine and loratadine may be more appropriate for people working in safety critical jobs.

Topics: Adolescent; Adult; Adverse Drug Reaction Reporting Systems; Aged; Cetirizine; Child; Child, Preschool; Consciousness Disorders; Female; Histamine H1 Antagonists; Humans; Infant; Infant, Newborn; Loratadine; Male; Middle Aged; Product Surveillance, Postmarketing; Sleep Stages; Terfenadine; Triprolidine