SEARCH · PubMed Health

Results for “ANTIHISTAMINICS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources

PubMed2004

Reversal of an antihistamine-induced coma with flumazenil.

Flumazenil is a competitive antagonist with specific action at the central benzodiazepine receptor. It is used when benzodiazepine intoxication is suspected. Its use has also been reported in cannabis intoxication, chloral hydrate overdose, hepatic encephalopathy, and alcohol intoxication. We report the case of a 7-month-old male infant with a depressed level of consciousness after intentional intoxication of antihistamines, whose mental status fully recovered after administration of flumazenil. To our knowledge, this is the first case in children where flumazenil has been reported to reverse antihistamine-induced coma.

Child Abuse↗

PubMed1978

Performance studies with antihistamines.

1 Effect of four antihistamines, chlorpheniramine (4 mg), clemastine (1 mg), promethazine (10 mg) and terfenadine (60 mg), on visuo-motor coordination and on subjective assessments of performance and well-being were compared with placebo in six healthy females from 0.5--7.0 h after morning ingestion of each drug. The study was double-blind, and the doses used were believed to be equally potent in their antihistaminic activity. 2 There was impaired performance 1.5 h (P less than 0.01) after chlorpheniramine, 3.0 h (P less than 0.05) and 5.0 h (P less than 0.01) after clemastine, and 3.0 h (P less than 0.01) and 5.0 h (P less than 0.001) after promethazine. It was not possible to establish effects on performance after ingestion of terfenadine. Subjective assessments of performance were not altered. 3 The subjects as a group reported improved alertness (P less than 0.05) and improved wakefulness (P less than 0.05) 0.5 h and 3.5 h respectively after ingestion of terfenadine, and were less energetic (P less than 0.05) 7.0 h after ingestion of chlorpheniramine. There were not other consistent changes in assessments of well-being.

Adult↗

PubMed1979

Effect of the antihistamines, brompheniramine maleate and triprolidine hydrochloride, on performance in man.

1 Effects of brompheniramine maleate (4 and 12 mg) and triprolidine hydrochloride (2.5 and 10 mg) on visuo-motor coordination, and on subjective assessments of performance, well-being and sleep were each studied in six subjects at 0.5, 1.5, 3.0, 5.0 and 7.0 h after ingestion. The doses refer to immediate and sustained release preparations respectively. 2. Triprolidine hydrochloride (2.5 mg) had an immediate effect on performance which persisted to 3.0 h, and the sustained release preparation (10 mg) impaired performance from 1.5 to 5.0 h. Brompheniramine maleate (4 mg) impaired performance from 1.5 to 3.0 h, and the sustained release preparation (12 mg) impaired performance at 1.5 h. There were no consistent changes in the subjective assessments of performance, or of well-being and sleep. 3. The studies emphasize the variable effects of antihistamines on performance, and suggest that effects on performance of sustained release preparations may be similar to those of the usual form. Sustained release preparations may provide an advantage in clinical practice if the antihistaminic activity is prolonged.

Adult↗

PubMed1982

Antihistamines and visual function: studies on dynamic acuity and the pupillary response to light.

1 Effects of three antihistamines, triprolidine (10 mg) in a sustained release form, astemizole (10 mg) and terfenadine (60 mg), have been studied on dynamic visual acuity and on the response of the pupil to light, together with critical flicker fusion, digit symbol substitution and cancellation, and subjective assessment of mood. The study was double-blind and effects were observed from 0.5-4.0 h after ingestion. 2 Triprolidine impaired dynamic acuity and reduced the threshold for subjective fusion of a flickering light, but there were no changes with astemizole or terfenadine. The diameter of the pupil and its response to light were not changed by the drugs. 3 Performance on digit symbol substitution and cancellation was not altered by the drugs. 4 Astemizole and terfenadine are promising antihistamines for those involved in skilled activity.

Adult↗

PubMed1987

Thymoxamine: lack of antihistaminic effects in clinical doses in man.

The purpose of this study was to investigate whether the alpha 1-adrenoceptor antagonist thymoxamine possesses antihistaminic activity in clinical doses in man, as has been reported on the guinea pig ileum in vitro. Five normal subjects were given on three separate occasions intravenous infusions of thymoxamine (0.15 mg kg-1 loading dose followed by 0.15 mg kg-1 h-1), chlorpheniramine (1.5 mg loading dose followed by 1.5 mg h-1) and normal saline (placebo). Intravenous bolus doses of histamine (1 and 2 micrograms kg-1) were given after pretreatment with propranolol 10 mg to block the beta-adrenoceptor agonist effects of the catecholamines released by the histamine injections. Histamine caused a dose-dependent reduction of FEV1 and FVC that was antagonised by chlorpheniramine but not by thymoxamine, suggesting that thymoxamine has no antihistaminic activity in the doses used in man. Thymoxamine caused a small enhancement of the bronchoconstrictor effect of the lower dose of histamine. The relatively selective action of thymoxamine makes it a suitable agent for the investigation of alpha 1-adrenoceptors.

Chlorpheniramine↗

PubMed1988

Ebastine: the effect of a new antihistamine on psychomotor performance and autonomic responses in healthy subjects.

1. Ebastine, through its carboxylic acid metabolite has antihistamine (H1-receptor) activity in man. 2. We have examined in a single blind placebo controlled study the effects of 10 mg and 50 mg of ebastine on cardiovascular, autonomic and psychomotor function in healthy subjects. 3. Ebastine had no effect on blood pressure or heart rate and there was no evidence of any anticholinergic activity on circulatory reflexes or salivation. 4. Ebastine did not impair psychomotor performance as assessed by critical flicker fusion at either dose. 5. Ebastine 10 mg had no effect on sedation measured by visual analogue scale or direct questioning, however ebastine 50 mg did cause a modest increase in indices of sedation. 6. Ebastine did not have detectable sedative properties at the 10 mg dose where long-lasting antihistamine effects can be demonstrated.

Adult↗

PubMed2006

Brain histamine H receptor occupancy of orally administered antihistamines measured by positron emission tomography with (11)C-doxepin in a placebo-controlled crossover study design in healthy subjects: a comparison of olopatadine and ketotifen.

AIMS: The strength of sedation due to antihistamines can be evaluated by using positron emission tomography (PET). The purpose of the present study is to measure histamine H(1) receptor (H(1)R) occupancy due to olopatadine, a new second-generation antihistamine and to compare it with that of ketotifen. METHODS: Eight healthy males (mean age 23.5 years-old) were studied following single oral administration of olopatadine 5 mg or ketotifen 1 mg using PET with (11)C-doxepin in a placebo-controlled crossover study design. Binding potential ratio and H(1)R occupancy were calculated and were compared between olopatadine and ketotifen in the medial prefrontal (MPFC), dorsolateral prefrontal (DLPFC), anterior cingulate (ACC), insular (IC), temporal (TC), parietal (PC), occipital cortices (OC). Plasma drug concentration was measured, and correlation of AUC to H(1)R occupancy was examined. RESULTS: H(1)R occupancy after olopatadine treatment was significantly lower than that after ketotifen treatment in the all cortical regions (P < 0.001). Mean H(1)R occupancies for olopatadine and ketotifen were, respectively: MPFC, 16.7 vs. 77.7; DLPFC, 14.1 vs. 85.9; ACC, 14.7 vs. 76.1; IC, 12.8 vs. 69.7; TC, 12.5 vs. 66.5; PC, 13.9 vs. 65.8; and OC, 19.5 vs. 60.6. Overall cortical mean H(1)R occupancy of olopatadine and ketotifen were 15% and 72%, respectively. H(1)R occupancy of both drugs correlated well with their respective drug plasma concentrations (P < 0.001). CONCLUSION: It is suggested that 5 mg oral olopatadine, with its low H(1)R occupancy and thus minimal sedation, could safely be used an antiallergic treatment for various allergic disorders. Abbreviations histamine H(1) receptor (H(1)R), histamine H(1) receptor occupancy (H(1)RO), dopamine D(2) receptor (D(2)R), positron emission tomography (PET), blood-brain barrier (BBB), binding potential ratio (BPR), distribution volume (DV).

Administration, Oral↗

PubMed1990

The antipruritic effect of a sedative and a non-sedative antihistamine in atopic dermatitis.

A double-blind, randomized, cross-over study was carried out on the effect of a sedative and a non-sedative antihistamine on 25 adults with atopic dermatitis. Intensity of itch was recorded using a computerized method for self-assessment (Pain-Track) and using conventional visual analogue scales. The antipruritic effect of 3 days of treatment with the non-sedative H1 antagonist terfenadine (60 mg b.i.d.) and with the sedative antihistamine, clemastine (2 mg b.i.d.) did not differ from that found with the placebo. Our findings support the view that histamine is not of importance in the pathogenesis of itch in atopic dermatitis.

Adolescent↗

PubMed2004

Effects of olopatadine hydrochloride, an antihistamine drug, on skin inflammation induced by repeated topical application of oxazolone in mice.

BACKGROUND: Olopatadine hydrochloride (olopatadine) is one of the second-generation antihistamines, which is prescribed for allergic disorders such as rhinitis, urticaria and eczema dermatitis. OBJECTIVES: To investigate the possible anti-inflammatory effect of olopatadine on the chronic contact hypersensitivity response to repeated topical application of oxazolone in mice. METHODS: The preventive and therapeutic effects of oral olopatadine were quantified by measurements of ear swelling, cytokine protein and mRNA expression in the ear lesion, and were compared with those of topical betamethasone 17-valerate (betamethasone). RESULTS: The ear receiving repeated applications of oxazolone exhibited erythema, oedema and abrasion. Both preventive and therapeutic administration of olopatadine (10 mg kg(-1) day(-1)) significantly inhibited the ear swelling and the increased production of interleukin (IL)-4, IL-1beta, granulocyte-macrophage colony-stimulating factor (GM-CSF) and nerve growth factor. In the histopathological analysis, olopatadine ameliorated epidermal hyperplasia and infiltration of inflammatory cells. Consistent with these results, olopatadine significantly reduced the increased expression of interferon-gamma and IL-4 mRNA. Although betamethasone (0.012 mg ear(-1) day(-1)) showed similar activities to olopatadine against these responses, it caused atrophy of the ear skin. CONCLUSIONS: These results indicate that olopatadine is an antihistamine agent having inhibitory activities against chronic inflammatory dermatitis, possibly resulting from its diminishing effect on elevated cytokines.

Adjuvants, Immunologic↗

PubMed1983

Astemizole: a new long-acting antihistamine in the treatment of seasonal allergic rhinitis.

Astemizole, a new long-acting antihistamine, (H1 receptor antagonist), 10 mg taken once daily was found to be an effective prophylactic treatment for the symptoms of allergic rhinitis in 75% (twelve from sixteen) of subjects in a double-blind placebo-controlled study. The success rate with placebo was less than 20% (three from sixteen). There were two treatment failures in highly atopic individuals taking the active drug. The classic side effects of antihistamines, most notably sedation, were minimal and reflected in the control group. Two subjects reported weight gain: one of these noted an increase in appetite during the 6-week trial period. Six of seven subjects who continued to take the drug for a longer period (up to 16 weeks) experienced marked weight gain: five of them reported an increase in appetite. Reactions to allergen skin tests were significantly reduced in patients taking astemizole.

Adolescent↗

PubMed1980

H2 antihistamines (cimetidine) and allergic-inflammatory reactions.

Experiments in the skin and synovialis have thrown new light on the allergic-inflammatory reactions. The inflammatory effect of histamine is thus due to stimulation of two different types of receptors in the vessels, i.e. histaminergic H1 and H2 receptors. Both types of receptors are of importance for the immediate cutaneous response to allergens and histamine. Treatment with a combination of H1 antagonists (classical antihistamines) and the H2 antagonist cimetidine will thus cause a much stronger inhibition of the urticarial reactions than treatment with the H1 and H2 antagonist alone. It is therefore probable that a combination therapy could have an advantage over the traditional treatment with classical antihistamines in urticaria and other histamine-mediated skin diseases. Histamine might also be of importance for the swelling of the joints in inflammatory diseases such as rheumatoid arthritis, and clinical trials with H1 and H2 antagonists are in progress.

Agranulocytosis↗

PubMed1988

Efficacy of an oral antihistamine, astemizole, as compared to a nasal steroid spray in hay fever.

The efficacy and side effects of the oral H1-antihistamine, astemizole, were compared with those of nasal beclomethasone in 158 adult birch-pollen allergic hay fever patients. 148 patients completed the 5-week, controlled trial which took place in Stockholm, May 1986, during the birch pollen season. Daily pollen counts were found to be at a rather low level throughout the study period. The effect and tolerability of both drugs were found to be excellent, although beclomethasone reduced nasal symptoms (sneezing, rhinorrhoea, blocked nose) significantly more effectively than astemizole. Eye symptoms were mild and equal in both groups. The results indicate that oral astemizole is an effective non-sedating antihistamine, though less so than nasal beclomethasone, in the treatment of nasal hay fever symptoms.

Administration, Oral↗

PubMed1989

Effect of a non-sedative antihistaminic (loratadine) in moderate asthma. A double-blind controlled clinical crossover-trial.

Seventeen patients with perennial asthma, stable on a moderate dose of inhaled steroid, participated in a crossover study comparing the clinical effect of a non-sedative, potent and highly selective H1 antagonist (loratadine 10 mg) with placebo. Each treatment period began with 2 weeks run-in followed by 8 weeks on either antihistamine or placebo. During the 8-week periods inhaled steroid was gradually tapered according to a fixed scheme. One patient was withdrawn from active treatment and three from placebo periods because of decreasing lung function (P greater than 0.1). Among the remaining 13 patients there was a threefold (1.8-4.8) decrease in the bronchial sensitivity to histamine during treatment with antihistamine compared to placebo (P less than 0.01). There was a trend in favour of active treatment with regard to changes in all symptom scores, lung function and use of escape medication, but these differences were not statistically significant. The increase in FEV1 was less than 5% of predicted normal (P less than 0.05). We concluded that the bronchial response to histamine can be attenuated by loratadine, an oral H1 receptor antagonist, but further studies are necessary to assess the clinical usefulness and place of loratadine in the therapy of asthma.

Adult↗

PubMed1997

Antihistamines in the treatment of asthma.

Antihistamines were investigated for use in asthma shortly after discovery over fifty years ago. Earlier compounds proved ineffective because of side effects: this class of drugs was not thought useful for asthma, and were actually considered contraindicated. More recent drugs have greater potency, fewer side-effects, and no evidence of adverse effects in asthma. There are some studies showing second generation antihistamines, especially cetirizine, improve certain parameters of asthma.

Asthma↗

PubMed2004

Antihistamines: do they work? Further well-controlled trials involving larger samples are needed.

Histamine is one of the most important steps in the phlogistic allergic reaction. Its activity is due to the link to specific receptors on the cellular surface. H1-receptors of second generation are the most currently prescribed drugs in allergic diseases for their high selectivity, little or no central sedative effect, rapid onset of action and long half lives. Antihistamines can modulate part of immunological mechanisms involved in the pathogenesis of allergic inflammation reducing mediator release and expression of adhesion molecules, regulating the release of cytokines, chemokines and consequently inflammatory cells recruitment. The anti-inflammatory effects of cetirizine, desloratadine and levocetirizine are reviewed. Quality of life is considered too, as a main parameter in a global evaluation of the antihistamine's effects.

Anti-Allergic Agents↗

PubMed2004

The ARIA/EAACI criteria for antihistamines: an assessment of the efficacy, safety and pharmacology of desloratadine.

BACKGROUND: The definition of allergic rhinitis and the classification of its severity and treatment have advanced in recent years following the publication of the Allergic Rhinitis and its Impact of Asthma (ARIA) document. The ARIA and the European Academy of Allergology and Clinical Immunology (ARIA/EAACI) have published a set of recommendations that outline the pharmacological and clinical criteria to be met by medications commonly used in the treatment of allergic rhinitis. METHODS: An international group of experts met to assess the profile of the antihistamine, desloratadine, under the ARIA/EAACI criteria. Data on desloratadine were collected from peer-reviewed clinical studies and review articles, which were corroborated and augmented by comprehensive public access documents from the European Medicines Evaluation Agency (EMEA). RESULTS AND CONCLUSION: Based on this systematic review, it was concluded that the efficacy, safety and pharmacology of desloratadine broadly meet the ARIA/EAACI criteria for antihistamines.

Animals↗

PubMed1996

Adverse central nervous system effects of older antihistamines in children.

Although older, potentially sedating, "first-generation" antihistamines (H1-receptor antagonists) are commonly used in childhood, their central nervous system (CNS) effects have not been well-documented in young subjects. We hypothesized that diphenhydramine and hydroxyzine would affect CNS function adversely in this population. Our objective was to evaluate the effects of these medications on central and peripheral histamine H1-receptors in children. Fifteen subjects with allergic rhinitis were tested before and 2-2.5 h after administration of diphenhydramine, hydroxyzine, or placebo in a double-blind, single-dose, three-way crossover study. Impairment of cognitive processing was assessed objectively by the latency of the P300 event-related potential (P300). Somnolence was assessed subjectively by a visual analog scale. Peripheral H1-blockade was assessed by suppression of the histamine-induced wheals and flares. At the central (Cz) and frontal (Fz) electrodes, diphenhydramine and hydroxyzine increased the P300 latency significantly (P < 0.05) compared to baseline. Hydroxyzine increased somnolence, as recorded on the visual analog scale, significantly compared to baseline (P < 0.05), with a similar trend for diphenhydramine (P = 0.07). Both antihistamines reduced histamine-induced wheals and flares significantly compared to baseline and compared to placebo. In children, diphenhydramine and hydroxyzine are effective H1-receptor antagonists, but both these medications cause CNS dysfunction, as evidenced by increased P300 latency, a measure of cognitive function, and by increased subjective somnolence.

Child↗

PubMed1976

Antagonism by some antihistamines of the amino acid-evoked responses recorded from the lobster muscle fibre and the frog spinal cord.

1 The effects of some antihistamines on the lobster muscle fibre and the frog spinal cord were investigated using intracellular and extracellular recordings, respectively. 2. On lobster muscle, histamine H1-blockers reversibly antagonized responses to bath-applied glutamate, aspartate and quisqualate but not responses to gamma-aminobutyric acid (GABA). Iontophoretic glutamate potentials were also reduced. Histamine (up to 1 mM) had no effect on this preparation. 3 The H1-antagonists produced a small increase in muscle membrane conductance and a slight hyperpolarization. These effects were largely unchanged in a low C1- bathing solution. Procaine (1 mM) decreased membrane conductance and did not affect responses to GABA or glutamate. 4 The H2-antagonist burimamide blocked both glutamate and GABA-evoked responses on the lobster muscle without affecting resting potential or conductance. 5 In the frog cord, bath-applied histamine produced ventral root depolarizations and dorsal root hyperpolarizations (sometimes biphasic responses). These effects were reduced by tetrodotoxin (TTX) but not by antazoline (H1-blocker) or burimamide; the latter reversibly antagonized responses to both glutamate and GABA on TTX-treated cords while antazoline was ineffective. 6 It is suggested that antihistamines can act as non-specific amino acid antagonists by interacting at the level of the receptor-coupled ionophores.

Amino Acids↗