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PubMedDate not supplied

The economic impact of payer policies after the Rx-to-OTC switch of second-generation antihistamines.

OBJECTIVE: As a result of the over-the-counter (OTC) introduction of loratadine, health plans have been struggling to determine the best policy to incorporate this change within their existing drug benefit structure for second-generation antihistamines (SGA). The objective of this study was to examine the economic impact of payer policies in response to the Rx-to-OTC switch of loratadine. STUDY DESIGN: Decision analysis was used to model the budgetary impact and cost-effectiveness of four policies for SGA benefits for the managed care organization (MCO), employer, and Medicaid perspectives separately. PATIENTS AND METHODS: Outcomes included direct medical costs and lost productivity (employers only), discounted, quality-adjusted life-years (QALYs) saved because of amelioration of allergic rhinitis symptoms and avoidance of unintentional injuries associated with the use of first-generation antihistamines (FGA). Bayesian probabilistic sensitivity analysis was conducted using second-order Monte Carlo simulation. RESULTS: Providing limited OTC and second-tier prescription benefits would cost approximately 0.13 dollars and 0.30 dollars compared to third-tier prescription benefits for employers and MCOs, respectively, and would save Medicaid 0.02 dollars per member per month (PMPM). Providing limited coverage for OTC loratadine while retaining second-tier prescription benefits for SGA was the optimal policy for a willingness to pay below 26,200 dollars per QALY for all payers. CONCLUSIONS: Offering second-tier prescription and limited OTC benefits provides greater effectiveness and is not significantly more expensive PMPM than discontinuation. Some of the drug savings from limiting coverage of prescription SGA may be attenuated by the cost of lost productivity and direct medical expenditures due to unintentional injuries associated with increased FGA use in addition to the increased cost of therapeutic substitutes.

Bayes Theorem↗
PubMedDate not supplied

Cost and utilization impacts of oral antihistamines in the California Medi-Cal program.

OBJECTIVES: Newer oral allergic rhinitis (AR) medications, the second-generation antihistamines (SGAs) have gained widespread acceptance because of their efficacy and reduced side effects relative to first-generation antihistamines (FGAs). There are no empirical studies comparing the costs of treatment of SGAs relative to FGAs. METHODS: We analyzed data from a 20% beneficiary sample (approximately 120,000 continuously enrolled beneficiaries per year) for the Medi-Cal Fee-for-Service program during 1999 to 2000. AR medications available under Medi-Cal included three SGA medications (loratadine, fexofenadine, and cetirizine) and over 200 FGA products containing either diphenhydramine or chlorpheniramine or both. Because multiple medications were evaluated, a sample selection model was estimated using a two-stage multinomial logistic--variance components regression framework. RESULTS: SGA medications have significantly lower total direct health-care treatment costs per patient than FGA medications with costs ranging from US 347 dollars to US 448 dollars less (P < 0.001), despite higher AR medication costs. Total drug expenditures were also not significantly different for patients using SGA or FGA medications despite SGA prescriptions averaging US 47 dollars higher than FGAs. Emergency department visits, inpatient admissions and physician office visits were also significantly lower for patients using SGA medications. CONCLUSIONS: Significant cost and utilization reductions were associated with all of the SGA medications relative to FGA drugs, despite their higher acquisition costs. If facing higher copayments for prescription AR drugs, many patients, particularly lower income patients, may choose cheaper over-the-counter (OTC) FGAs rather than SGAs. Our analysis finds this might lead to increased overall health-care treatment costs, unless Medicaid and health insurance plans subsidize OTC AR medications.

Administration, Oral↗
PubMed1999

Lichenoid and subacute cutaneous lupus erythematosus-like dermatitis associated with antihistamine therapy.

The authors report the occurrence of lichenoid and/or subacute lupus erythematosus-like eruptions in a group of patients receiving agents with antihistaminic properties. In 1 of the patients the eruption clinically resembled lichen planus, while in 5 patients the eruption resembled subacute cutaneous lupus erythematosus (SCLE). At a light microscopic level all cases showed a lichenoid dermatitis and in 4 cases the lesions were interpreted as representing subacute lupus-like eruptions by virtue of the presence of alternating cell poor and lichenoid interface dermatitis, suprabasilar lymphocytosis around degenerating keratinocytes, and dermal mucinosis. Despite the resemblance at a clinical and light microscopic level to SCLE, anti-Ro seropositivity could not be established in any of the cases. One case, however, did demonstrate antihistone antibodies in concert with a high antinuclear antibody titer. A causal association was implicated by virtue of lesional resolution following drug withdrawal. The association of cutaneous eruptions resembling SCLE with antihistamine intake is seemingly a novel one. The possible pathogenetic basis of the eruptions is discussed.

Aged↗
PubMed2006

Pediatric primary cutaneous marginal zone lymphoma: in association with chronic antihistamine use.

Primary cutaneous marginal zone lymphoma of the mucosa-associated lymphoid tissue predominantly occurs in adults and is rare in children. There have been no prior reports of this lymphoma occurring in American children. We present a case of a 15-year-old male with a history of atopic diathesis and chronic use of antihistamine agents who presented with an asymptomatic lesion on his left forearm of 6 months duration. Because histopathological and immunohistochemical studies were compatible with marginal zone lymphoma, and the patient had no associated extracutaneous disease, the diagnosis of primary cutaneous marginal zone lymphoma was rendered. Based on the patient's past medical history prior to appearance of lesion, it was postulated that the development of lymphoma was associated with the ingestion of antihistamines and further propagated by his underlying atopic diathesis.

Adolescent↗
PubMed1999

Antihistamines in the management of allergic pruritus in dogs and cats.

Antihistamines clearly have a place in the management of pruritus in the atopic dog and cat and, in this paper, important aspects of pharmacology and pharmacokinetics, adverse effects and precautions, and clinical use of these compounds are reviewed. Successful use of antihistamines is dependent on, among other considerations, the adherence to recommended doses and frequencies of administration, the recognition and control of concurrent and secondary factors, the willingness to try several different compounds, and the realisation that these agents are best employed in a preventive fashion.

Animals↗
PubMed1986

Antihistamine-sensitive active vasodilatation in the perfused hindquarters of the rat.

The innervated, constant flow perfused hindquarters of the rat have been used to evaluate post-stimulation vasodilatation, which is a model of active reflex vasodilatation in this species. The vasodilatation resulting from lumbar sympathetic stimulation was dependent on stimulation frequency and duration. Maximal vasodilatation (16 +/- 2%) was at 8 Hz for 15 s, while markedly reduced vasodilatation was seen after stimulation for longer than 30 s at all frequencies tested. The vasodilatation was transient. Atropine (2.0 mg kg-1 i.v.) failed to attenuate post-stimulation vasodilatation at a time when hindquarter vasodilatation to i.a. acetylcholine had been abolished. The H1 antihistamine, tripelennamine (2.5 mg kg-1 i.v.) significantly reduced (77%) post-stimulation vasodilatation relative to controls at a time when hindquarter vasodilatation due to i.a. histamine was essentially abolished. Reactive hyperaemia is an unlikely cause of vasodilatation since it is not blocked by H1 antihistamines; 60 s post-occlusion hyperaemia also, was not demonstrable. These data suggest that there is an active component of baroreceptor-mediated vasodilatation in the rat and that histamine, rather than acetylcholine, could be a mediator of this vasodilatation.

Animals↗
PubMed1997

Interactions of the nonsedating antihistamine loratadine with a Kv1.5-type potassium channel cloned from human heart.

The use of nonsedating antihistamines may, on rare occasions, be associated with cardiac arrhythmias. This could be due to blockade of voltage-dependent K+ channels in the heart, leading to a prolongation in repolarization in the human myocardium. For this reason, we examined the effects of the nonsedating antihistamine loratadine on a rapidly activating delayed-rectifier K+ channel (Kv1.5) cloned from human heart and stably expressed in HEK 293 cells or mouse Ltk- cells. Using patch-clamp electrophysiology, we found that loratadine blocked Kv1.5 current measured from inside-out membrane patches at concentrations of > or = 100 nM, resulting in an IC50 value of 808 nM at +50 mV. The drug enhanced the rate of Kv1.5 current decay, and block was enhanced at membrane potentials near threshold relative to higher potentials. Loratadine did not alter the kinetics of Kv1.5 current activation or deactivation. Unitary Kv1.5 currents were recorded in cell-attached patches. At the single-channel level, the main effect of loratadine was to reduce the mean probability of opening of Kv1.5. This effect of loratadine was achieved by a reduced number of openings in bursts and burst duration. Finally, loratadine (10 microM) failed to inhibit HERG K+ channel currents expressed in Xenopus laevis oocytes. It is concluded that loratadine is an effective blocker of Kv1.5 that interacts with an activated state or states of the channel. This interaction suggests a potential for loratadine to alter cardiac excitability in vivo.

Animals↗
PubMed1984

Comparative trial of two non-sedative H1 antihistamines, terfenadine and astemizole, for hay fever.

Ninety patients participated in a randomised, double blind, placebo controlled comparison of terfenadine with astemizole in the treatment of hay fever. They entered the trial as a cohort before the grass pollen season and recorded daily their symptoms of itching eyes, sneezing, running nose, and blocked nose on visual analogue scales in diary cards. Over the eight weeks of the trial astemizole was significantly better than either terfenadine or placebo in alleviating itching eyes, sneezing, and running nose (p less than 0.0001) but no better than placebo for the treatment of blocked nose. The placebo was significantly better than terfenadine for the treatment of running nose and blocked nose (p less than 0.002). Neither of these H1 antihistamine drugs was associated with sedative adverse effects despite significantly inhibiting histamine induced skin weal responses. These results suggest that astemizole is a satisfactory non-sedative H1 antihistamine for maintenance treatment of hay fever. Terfenadine is ineffective by comparison.

Adolescent↗
PubMed1996

Cardiac actions of antihistamines.

Two of the nonsedating antihistaminic drugs, terfenadine and astemizole, have recently been recognized in rare cases to induce the syndrome of torsades de pointes, i.e. QT interval prolongation and life-threatening ventricular tachycardia. Each was found to prolong cardiac repolarization when its metabolic elimination was impaired, such as by liver disease or drugs that inhibit the 3A family of cytochrome P450. In vitro studies indicate that this action is due to blockade of one or more of the cardiac potassium channels that determine the duration of the action potential. Prescription guidelines are now available to reduce the risk of developing arrhythmias with these two drugs. Two agents recently marketed in the United States, Ioratidine and cetirizine, appear to lack the ability to prolong repolarization and induce torsades de pointes. Evaluation of the potential cardiac actions of investigational antihistamines is essential and may be of value for some of the older conventional agents.

Animals↗
PubMed1985

Suppression of endotoxin-induced corticosterone secretion in rats by H1-antihistamine.

Corticosterone (CS) secretion is stimulated in rats by an intraperitoneal injection of bacterial lipopolysaccharide (LPS) or by subjecting the animals to immobilization stress. LPS injection caused a significant increase in the lung histamine level and a sharp reduction in the number of intact peritoneal mast cells. Injection of compound 48/80, a histamine liberator, provoked an increase in the histamine levels of the blood and lung and a decrease in the number of intact peritoneal mast cells with a concomitant increase in CS secretion. Administration of histamine, at a dose of 10 mg/kg, induced a marked increase in CS release. LPS-induced CS secretion was attenuated by pretreatment with an H1-antihistamine, promethazine (PMZ), whereas an H2-antihistamine, metiamide, had no effect. In contrast, PMZ was ineffective on CS release provoked by immobilization stress. These results suggest that LPS-induced CS release is mediated, in part, by histamine released in the peripheral tissues, whereas an immobilization stress-induced increase is not mediated by the amine.

Animals↗
PubMed1981

Inhibition of allergen-mediated histamine release from human cells by ketotifen and oxatomide. Comparison with other H1 antihistamines.

We have studied the ability of four H1 antihistamines, ketotifen, oxatomide, clemastine and promethazine, and of disodium cromoglycate (DSCG) to inhibit in vitro histamine release mediated by antigen from passively sensitized human lung and from basophilic leukocytes. Anaphylactic histamine release from human leukocytes is inhibited in a comparable fashion by oxatomide, clemastine and promethazine at concentrations just below those inducing histamine release in the absence of antigen. Ketotifen causes a significantly weaker inhibition without inducing histamine release and DSCG is not at all active in this model. On human lung, oxatomide, clemastine and promethazine give a strong and similar inhibition which is linearly related to the dose. Ketotifen markedly differs in this respect, inhibiting according to a bell-shaped dose-response curve and at concentrations closely comparable to that of DSCG. Thus, we confirm that H1 blockers, such as clemastine and promethazine, inhibit anaphylactic histamine release from basophils and human lung but only at high concentrations which may be cytotoxic. Oxatomide behaves very much like these antihistamines. Ketotifen, on the other hand, gives in both models a different pattern of inhibition, closely mimicking that of DSCG. This suggests that the antianaphylactic activity of ketotifen is not related to its H1 blocker properties and that this effect may be relevant to its therapeutic activity.

Allergens↗
PubMed1988

Effect of antihistamines on antigen-induced increase of rat tracheal mucous gel layer thickness.

The effect of orally administered H1 and H2 antihistamines on antigen-induced changes in tracheal mucous gel layer thickness of actively sensitized rats was determined. Cimetidine and ranitidine, H2 antagonists, produced dose-dependent inhibition of antigen-induced increase in gel thickness at doses ranging from 0.32 to 3.16 and from 0.10 to 1.0 mg/kg, respectively. H1 antagonists - like chlorpheniramine, diphenhydramine, and pyrilamine which possess anticholinergic properties - tended to enhance the antigen-induced gel thickening in a dose-dependent fashion, while astemizole and terfenadine had no effect. These data indicate that an antigen-induced increase of rat tracheal mucous gel layer thickness may result from stimulation of the H2 receptor, while histamine operating at the H1 receptor does not play a role. Therefore, an antihistamine that possesses both H1 and H2 antagonist properties while lacking anticholinergic properties appears to be the most appropriate for use in patients with asthma and associated bronchorrhea.

Animals↗
PubMed1985

Placebo-controlled study of the efficacy of topical antihistaminics against histamine-induced pruritus.

2 antipruritic ointments, when compared to placebo, were ineffective against histamine-induced itching applied in 2 volunteers after the intracutaneous injection of histamine. Testing of 11 topical antihistaminics after pretreatment for 30 and 60 min on 12 volunteers showed that some of the preparations reduced the histamine-induced itching significantly, while others were able to inhibit itching only slightly or were very close to placebo. Pain from pin pricks could not be attenuated significantly by pretreatment with the topical antihistaminics at any time.

Administration, Topical↗
PubMed1987

Intranasally and orally administered antihistamine treatment of experimental rhinovirus colds.

Although antihistamines are widely used for symptomatic treatment of seasonal (allergic) rhinitis, the role of histamines in the pathogenesis of infectious rhinitis is not clear. Two antihistamines, orally administered chlorpheniramine maleate (CM) and diphenhydramine hydrochloride (DH) administered by intranasal spray, were used under double-blinded, randomized, placebo-controlled conditions to assess both tolerance and efficacy in volunteers with experimental rhinovirus (RV) colds. In the initial trial, CM (4.0 mg per treatment) was ingested 4 times daily for 4 days beginning 24 h after intranasal inoculation of RV type 29 in susceptible volunteers. In the second trial, DH was sprayed intranasally 4 times daily (2 mg per treatment) for 5 days beginning 24 h after inoculation of RV type 39. Clinical colds occurred in 60% of the CM group (n = 13) and 73% of the placebo (n = 15) in the first study, and in 66% of the DH group (n = 12) compared with 81% in the placebo group (n = 11) in the second. Both CM and DH were well tolerated but had no significant effects on nasal symptoms or nasal mucus production. The findings provide additional evidence against an important role for histamine in the pathogenesis of nasal symptomatology in rhinovirus colds.

Administration, Intranasal↗
PubMed1979

The effects of H1 and H2 antihistamines on histamine inhalation challenges in asthmatic patients.

This study was designed to examine the effect of an H1 antihistamine, chlorpheniramine, an H2 antihistamine, cimetidine, and the combination of chlorpheniramine and cimetidine on histamine-induced bronchoconstriction in a double-blind, randomized protocol on 11 patients with asthma. Each patient underwent a histamine inhalation challenge on 5 separate days. After a control day, histamine inhalation challenges were performed 2 h after the administration of a single oral dose of 8 mg of chlorpheniramine, 300 mg of cimetidine, the combination of chlorpheniramine and cimetidine, or placebo. Baseline pulmonary function measurements were not significantly altered by the 4 treatments. Body plethysmography data and measurements from the forced vital capacity maneuver were obtained before and after the histamine inhalation challenges. The provocation dose of histamine that produced a 20% decrease in forced expiratory volume in one second, a 35% decrease in mean forced expiratory flow during the middle half of the forced vital capacity, and a 50% decrease in specific airway conductance was significantly increased after administration of chlorpheniramine (p less than 0.002) and decreased after administration of cimetidine (p less than 0.02), where as no significant effect was noted after the combination of chlorpheniramine and cimetidine. The results suggest the presence of both H1 and H2 receptors in the airways of asthmatic patients.

Adolescent↗
PubMed1983

Antihistaminic versus anticholinergic effects of atropine on canine trachealis muscle.

To determine antihistaminic versus anticholinergic effects of atropine in airway smooth muscle, we used an in vitro preparation of canine trachealis muscle strips and determined atropine's effect on contractile responses induced by histamine or by electrical field stimulation of cholinergic nerves. In the first series of experiments, 53 strips had initial responses to field stimulation determined and were then randomly assigned to a control group or to a group treated with atropine before field stimulation was repeated and histamine was given. Atropine in concentrations of 10(-8), 10(-7), and 10(-6) M decreased the response to field stimulation to 61.4, 10.5, and 0% of the initial response, respectively, but had no effect on the responses to histamine. In the second series of experiments, 24 strips were treated with indomethacin to prevent histamine tachyphylaxis; these strips had initial responses to both field stimulation and histamine determined and were then assigned to a control group or to a group treated with atropine before field stimulation and histamine were repeated. In these experiments, a concentration of atropine (10(-6) M), which again completely blocked the response to field stimulation, still had no effect on histamine-induced contraction. We conclude that atropine in a concentration that completely blocks the response to cholinergic nerve stimulation has no antihistaminic effect.

Animals↗
PubMed2003

Desloratadine: a nonsedating antihistamine.

OBJECTIVE: To review information on desloratadine, a nonsedating antihistamine. DATA SOURCES: An English-language MEDLINE search was conducted (1966-July 2002). References of identified articles were subsequently reviewed for additional data. Schering Corporation provided unpublished information. STUDY SELECTION/DATA EXTRACTION: Articles and abstracts pertaining to desloratadine were considered for inclusion, with emphasis on randomized, placebo-controlled, double-blind trials. DATA SYNTHESIS: Desloratadine is approved for the treatment of symptoms associated with seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR), and chronic idiopathic urticaria (CIU) in patients aged > or =12 years. In placebo-controlled trials, desloratadine demonstrated superior efficacy as a once-daily treatment of SAR, PAR, and CIU. Data suggest that desloratadine has antiinflammatory and decongestant activity. CONCLUSIONS: Desloratadine appears to be a "me-too" agent, with no major differences compared with other second-generation antihistamines.

Adult↗