Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042109 (urticaria)
 6,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histamine was the first allergic mediator identified in the early part of this century. It has three defined receptors, but most effects of histamine in allergic reactions are through the H1 receptor. The first H1 antagonists were introduced into clinical use in the late 1940s, and drugs of this class are still the preferred initial choice for management of allergic rhinitis and urticaria. The first-generation drugs were characterized by nonspecific binding to many receptors and penetration of the blood-brain barrier, resulting in multiple side effects. Within the central nervous system (CNS), interference with normal histamine binding to the H1 receptor is associated with drowsiness and psychomotor impairment. The second-generation drugs have a much improved benefit/adverse effect profile, largely based on greater potency, receptor specificity, and lower CNS penetration. The potency of antihistamines for blocking H1 receptors can be compared by their inhibition of the cutaneous wheal and flare response to histamine. These drugs seem to have additional antiallergic properties related to blockade of mediator release and interference with cellular recruitment and activation. Clinical trials comparing the efficacy of antihistamines in rhinitis and asthma are reviewed. Recent studies have explored the potential of antihistamines to prevent the progression of allergy and their enhanced efficacy when combined with leukotriene antagonists.
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PMID:Molecular pharmacology of second-generation antihistamines. 1089 14

This trial was designed to study the efficacy and tolerability of azelastine in controlling symptoms of chronic idiopathic urticaria, using ebastine as validation group. Fifty-two adult patients were randomised to receive azelastine (4 mg), ebastine (10 mg) or 18 placebo for 21 days. Patients were required to visit the investigating physicians on three different occasions (days 0, 7 and 21). On each of these three study days, investigators assessed itching, wheals and erythema, based on a 4-point scale, and quality of life using a visual-analogue scale and subscale 9 of the Short Form 36 (SF-36) Health Survey. Patients entered daily assessments of itching on diary cards also using a 4-point scale. Furthermore, investigators assessed global efficacy and tolerability of the study medication on day 21 or upon premature discontinuation of the trial. Side effects and compliance were evaluated on each visit. A statistically significant reduction in itching was found for both active treatments compared with placebo. These improvements, which were statistically significant already after 1 day of treatment, continued over the course of 3 weeks. Additionally, both azelastine and ebastine were effective in improving symptoms such as wheals and erythema when compared to placebo. The quality-of-life parameters were unaffected by either treatment. Taste perversion (2 cases) and somnolence (1 case) were the only adverse drug reactions of azelastine. Ebastine, however, seemed to cause more often and more severe symptoms such as fatigue, sleepiness and asthenia. Global assessments of efficacy and tolerability performed by the investigators, also favoured azelastine. In conclusion, both azelastine and ebastine are effective and safe drugs, able to control symptoms of chronic idiopathic urticaria since the first day of treatment, and along a period of 3 weeks.
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PMID:Azelastine tablets in the treatment of chronic idiopathic urticaria. Phase iii, randomised, double-blind, placebo and active controlled multicentric clinical trial. 1131 66

Fexofenadine is a non-sedating antihistamine indicated for relieving symptoms from allergic conditions with a rapid onset of action without cardiotoxic risks. Controlled studies showed that fexofenadine 180 mg daily provides significant relief of symptoms of chronic idiopathic urticaria (CIU). The purpose of this study was to demonstrate the efficacy and safety of fexofenadine 60 mg twice daily in Thai patients with CIU in a multicenter trial. Patients were assigned to receive twice daily doses of fexofenadine 60 mg for 6 weeks. Patients rated symptom severity every night, investigators rated patients' signs and symptoms at recruitment and at 1, 3 and 6 weeks. Ninety eight out of 108 patient (90.7%) completed the study. The patients reported 95 per cent improvement and, of those, 91 per cent had very favorable responses (excellent 15%, very good 42%, good 30%, fair 8%). The objective assessment by their physicians paralleled those responses. Fexofenadine provided a rapid clinical response that was significantly superior to before treatment in relieving symptoms of CIU (p < 0.001). Adverse events occurred in 20 cases (18.5%), mostly mild headache and drowsiness. Fexofenadine 60 mg twice daily provides effective relief of the symptoms of CIU with minimal adverse events.
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PMID:Multicenter study of the efficacy and safety of fexofenadine 60 mg. twice daily in 108 Thai patients with chronic idiopathic urticaria. 1133 71

An extensive body of research exists on CNS effects of H1-antagonists. There is great interest in this area due to the well-known adverse CNS effects associated with first-generation H1-antagonists, and the many new second-generation agents claiming to have nonsedative properties. Because the CNS effects of H1-antagonists are complex and cannot be reflected in one measurement, a variety of assessments of CNS function are required. These range from the subjective (e.g., self-rating of drowsiness) to the objective (e.g. 24 h EEG sleep latency, P300), and from the simple (e.g., critical flicker fusion) to the complex (e.g., actual driving). When these tests are applied to the evaluation of the H1-antagonists currently available, it is clear that there is a real distinction between the older first-generation H1-antagonists and the newer second-generation ones. At the recommended dosages, all the second-generation H1-antagonists are clearly less sedating in more patients than their predecessors. These newer medications do not cross the blood-brain barrier readily; are highly specific for H1-receptors; have little to no anticholinergic, antiserotoninergic, or anti-alpha-adrenergic effects; and do not enhance the adverse CNS effects of alcohol or other CNS-active substances such as the benzodiazepines. Since most second-generation H1-antagonists are found to be relatively nonsedating, their benefit/risk ratios will be determined more by their other properties such as non-CNS adverse effects (e.g., potential to cause cardiac arrhythmias), potency, onset of action, duration of action, ease of administration, and cost. The future role and usefulness of the older sedating H1-antagonists, given the availability of the safer second-generation agents, are unclear at the present time. When H1-antagonist treatment is indicated, physicians should recommend an effective H1-antagonist with a favorable clinical pharmacology profile and a wide margin of safety in patients of all ages. The common, often subclinical, adverse CNS effects produced by the old H1-antagonists remain a major concern and, therefore, these compounds are no longer medications of choice in the treatment of allergic rhinitis, allergic conjunctivitis, or urticaria.
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PMID:H1-antihistamines and the central nervous system. 1211 23

Old generation H1-type antihistamines are the standard therapeutic option for acquired cold urticaria (ACU), but adverse effects are common. New antihistamines are well tolerated but efficacy is often poor. The present study aims to evaluate efficacy and safety of cinnarizine in the treatment of ACU patients intolerant to old antihistamines and resistant to new drugs. We studied 14 patients (4 males and 10 females). Mean duration of the disease was 48.9 (range 7-102) months. Cold cube test was positive in 78.6 % of patients. Cold urticaria was idiopathic in 10 (71.4 %) patients. Cryoglobulins were detected in the serum of 4 cases (28.6 %). Cinnarizine (25 mg t.i.d.) was administered for 3 months, and then it was gently tapered off and stopped within 2 months. A complete or good response was obtained in 8 (57.1 %) and 2 (14.3 %) patients, respectively. Only two patients were unresponsive (21.4 %). Tapering off or stopping cinnarizine was followed by the relapse of cold urticaria in 7 cases (50.0 %). These patients were amenable to a second treatment cycle. Six patients (42.9 %) had a persistent remission. A patient interrupted the therapy because of severe vertigo. Three patients reported mild and transitory adverse effects including epigastralgia, weight gain and drowsiness. In conclusion, cinnarizine at high doses may be considered as an effective and well-tolerated treatment for ACU.
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PMID:Cinnarizine is a useful and well-tolerated drug in the treatment of acquired cold urticaria (ACU). 1260 83

We report the case of a 46-year-old man who tolerated 50 mg per day of cetirizine for the treatment of chronic idiopathic urticaria. The patient denied any sedation or somnolence and had no difficulty performing routine daily functions including driving. He had tried other antihistamines, including fexofenadine, loratadine, and hydroxyzine without improvement.
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PMID:High dose cetirizine: a case report. 1276 7

Histamine H1 receptor antagonists, or antihistamines, are very effective for treatment of various allergic disorders such as seasonal rhinitis and urticaria. Sometimes antihistamines induce sedative CNS side effects that might result in dangerous traffic accidents. That is why a lack of sedation is important for development of new antihistamines. It is clear that all antihistamines have a potential to produce subjective (sleepiness, fatigue etc.) and objective sedation (impaired performance), dependent on the histaminergic mechanisms involved in the control of arousal. We have proposed the usefulness of H1 receptor occupancy measurement with Positron Emission Tomography (PET) using 11C-doxepin as a tracer. The PET measurement is currently included as one of the three major factors defined by the international Consensus Group on New Generation Antihistamines (CONGA) for evaluation of antihistamines: 1) incidence of subjective sleepiness, 2) objective and psychomotor functions, and 3) PET measurement of H1 receptor occupancy. Merit of PET measurement is that we can directly calculate the receptor occupancy for each separate drug while the former two should be discussed based on the difference between placebo and active placebo. PET will be used more actively in the development of various new drugs in future.
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PMID:[A potential of positron emission tomography in the drug development of non-sedative antihistamines]. 1472 29

Atopic conditions include allergic rhinitis, atopic eczema, allergic conjunctivitis and asthma. Doctors and patients can choose from a variety of antiallergy medications, testifying that no one medication will suffice to treat all symptoms and that each has a different side-effect profile. Antiallergy medications target histamine receptors, as histamine release contributes to the unpleasant symptoms of itching, tearing, runny nose and skin urticaria. The ideal antihistamine would control the symptoms of atopic disease but cause very few side effects. Traditionally, unwanted effects include drowsiness and somnolence due to CNS depression, and digestive tract problems such as loss of appetite, nausea, vomiting and constipation or diarrhea. Some antihistamines also have anticholinergic effects that are mediated by muscarinic receptors. These atropine-like actions, which can affect the cardiovascular system, are sufficiently prominent in some drugs to be manifest during clinical usage. Epinastine hydrochloride minimally penetrates the blood/brain barrier and has almost no effect on the muscarinic receptors. This drug is marketed as having very few CNS-depressant side effects, few drug interactions and gastrointestinal side effects, and a low risk of cardiotoxicity.
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PMID:Epinastine hydrochloride for atopic disease. 1551 Feb 39

The only venomous reptile that naturally occurs in Poland is the adder or common viper (Vipera berus). Its bites are not of great epidemiological importance, but in some cases serious life-threatening symptoms may appear. The most common symptoms of adder envenomation are: local edema, reddening and pain of the bitten site and also the general symptoms coming from the alimentary tract (vomiting, diarrhoea, abdominal pain), the circulatory system (hypotension, shock, ECG abnormalities), the central nervous system (sleepiness, vertigo, disorientation, loss of consciousness), hematological symptoms (leukocytosis, hemolysis, coagulopathy) and allergic symptoms (fever, urticaria, angio-oedema). In the present study we described the case of a twenty-year-old patient hospitalized at the Toxicology Department of the Collegium Medicum UJ after a viper bite. Except for some above-mentioned symptoms he also developed ocular symptoms like ptosis and blurred vision. Such symptoms after the common viper bite have not been described in the literature till now. The cause of them seems to be an intense allergic reaction in the region of the orbit and eyelids all the more so because the patient had the positive allergy history. However, taking into account the latest reports from the literature, a neurotoxic action of some components of the Vipera berus venom may also play a role. Because of the developing general symptoms a specific equine antivenom was administered to the patient, apart from the supportive care, without any serious side effects that usually are observed after the use of such a kind of sera. It is thought that the sheep antivenom is better than the equine one considering a lack of allergic side effects. As a result of applied treatment the local and general symptoms including ocular symptoms subsided.
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PMID:[Envenoming by common viper (Vipera berus)--subject still exists...]. 1552 21

Along with antibiotics, antihistamines are the most widely used systemic drugs in dermatology. This is attributable to the major role played by histamine in common diseases such as urticaria and atopic eczema. Of the currently recognised four subtypes of G protein-coupled histamine receptors, only the H1 and H2 subtypes have been positively identified in human skin. Traditionally believed to be competitive antagonists of histamine, H1 and H2 antihistamines are now considered to behave as inverse agonists. By consensus, H1 antihistamines are classified as 'first generation' (associated with troublesome side-effects including somnolence, anti-adrenergic and atropine-like actions) and 'second-generation' compounds (in which these side-effects are reduced or absent). The main indications for H1 antihistamines in skin are suppression of pruritus in urticaria and atopic eczema, both of which are associated with increased mast cell numbers and tissue histamine levels. However the evidence basis for use in atopic eczema is ambiguous and controversial, even though these drugs are widely used in practice. Currently, significant side-effects are mainly confined to the first-generation compounds and are especially troublesome in the elderly. Psychomotor impairment may persist throughout the day following administration. Anti-cholinergic and anti-alpha-adrenergic blockade and cardiotoxicity (torsade de pointes) may also occur with first-generation antihistamines. Two early low-sedation second-generation antihistamines caused arrhythmias in a small number of patients but these compounds have now been withdrawn. Generally, the second-generation H1 antihistamines are well tolerated.
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PMID:Antihistamines in dermatology. 1601 20


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