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 361 records · Page 20Linked to original sources

PubMed1988

The pharmacokinetics, antihistamine and concentration-effect relationship of ebastine in healthy subjects.

1. The kinetics and effects of ebastine 10 and 50 mg were studied after oral dosing in healthy subjects. 2. The parent drug was extensively metabolised during the first pass to its carboxylic acid derivative, carebastine. 3. The pharmacokinetics of carebastine were linear over the dose range studied and the terminal elimination half-life was 10.6 +/- 2.6 and 12.5 +/- 1.9 h respectively after 10 and 50 mg of ebastine. 4. Antihistamine (H1-receptor) activity was examined with intradermal histamine (2 micrograms). Oral ebastine reduced the histamine wheal area for up to 24 h and also reduced subjective local pain. 5. Antihistamine activity correlated well with plasma levels of carebastine in individual subjects. 6. Ebastine appears to have potential as an antihistamine for once a day dosing.

Adult↗

PubMed2006

Facial thermography is a sensitive tool to determine antihistaminic activity: comparison of levocetirizine and fexofenadine.

AIMS: To assess the antihistaminic activity of levocetirizine and fexofenadine 2 h and 24 h after drug administration using facial thermography and to compare the results with those using well-established parameters of antihistaminic activity in the nose and skin. METHODS: This was a randomized, double-blind, three-treatment, three-period, single-dose, cross-over study in healthy males taking levocetirizine 5 mg, fexofenadine 120 mg or placebo. The primary endpoint was nasal skin temperature after nasal histamine challenge recorded for 20 min at 2 and 24 h after drug intake. The secondary endpoints were nasal symptoms and a histamine skin prick test. RESULTS: Thirty subjects were randomized. At 2 h after drug intake the inhibition of the nasal temperature increase from baseline was not significantly different between levocetirizine and fexofenadine. At 24 h it was significantly more pronounced after levocetirizine than fexofenadine (difference: least-squares mean: -0.13 degrees C; P < or = 0.024, 95% CI -0.24, -0.02). Both drugs significantly reduced (P < or = 0.001) the mean temperature increase from baseline compared with placebo at 2 and 24 h (least-squares mean increase and (95% CI): levocetirizine, -0.28 degrees C (-0.42, -0.14) and -0.32 degrees C (-0.43, -0.21); fexofenadine -0.35 degrees C (-0.49, -0.21) and -0.19 degrees C (-0.30, -0.08), respectively). Results of nasal symptom score and wheal and flare were consistent with the thermography results. CONCLUSIONS: Facial thermography is an objective, non-invasive and sensitive method to study antihistaminic activity at the nose level. Levocetirizine and fexofenadine demonstrate the same activity at 2 h after drug intake, but levocetirizine has a more sustained activity at 24 h.

Adolescent↗

PubMed1980

Dyes and preservatives in oral antihistamines.

Antihistamines are commonly used in the treatment of urticaria. Some antihistamines contain dyes and preservatives which have themselves been shown to produce or exacerbate urticaria; the presence of these substances is not indicated in the usual formularies and a list of commonly prescribed antihistamines is presented, detailing the azo dyes, other dyes and preservatives contained therein.

Administration, Oral↗

PubMed1982

Prophylactic antihistamines in the management of radiographic contrast reactions.

Two hundred and twenty consecutive patients, referred for intravenous pyelography, were assessed for adverse reactions. The effect of prophylactic antihistamines was evaluated. Patients were divided randomly into control, saline or chlorpheniramine treated groups. Changes in serum total haemolytic complement (CH50) and immune complexes (IC) at times 0, 1, 5, 10 and 20 min after injection of radiocontrast material were assayed. Forty-two of the 220 patients suffered reactions, classified clinically into allergic and non-allergic types. There was no difference in the incidence of allergic reactions between control and saline groups. However, significantly less (P less than 0.05) allergic reactions were noted in the antihistamine pre-treatment group. Depressed CH50 occurred in forty-three, of eighty-eight patients tested and persisted for at least 20 min in twenty-two. There was no correlation between CH50 depressions and clinical symptoms. The IC remained unchanged throughout. In conclusion, prophylactic antihistamines may diminish the incidence of allergic reactions. Complement activation occurs in a large number of patients, unrelated to symptomatology, and does not appear to be the only factor responsible for adverse reactions.

Chlorpheniramine↗

PubMed1992

Comparative inhibition profiles of three non-sedating antihistamines assessed by an extended Lewis model.

Antihistaminic drugs are widely prescribed across a multitude of medical specialties such as Allergy and Dermatology. The potentially serious sedative effect of these valuable agents has previously restricted their full use and the choice of drug has been dictated more by individual patient acceptability than by any laboratory demonstrations of comparative efficacy. Unsurprisingly therefore, there is a trend towards prescribing those newer preparations which leave the central nervous system unclouded. We have studied the most frequently prescribed non-sedating antihistamine preparations, terfenadine (Triludan, Triludan Forte), cetirizine (Zirtek) and loratadine (Clarityn) in pharmacodynamic and relative efficacy trials using a quantifiable and reproducible extension of the classic Lewis model. The results indicate that two preparations, terfenadine 120 mg (Triludan Forte) and cetirizine 10 mg (Zirtek) are superior to their immediate rivals in degree of efficacy and/or speed of action. These results should assist clinicians in the positioning of effective, rapidly acting antihistamines for the symptomatic treatment of immediate hypersensitivity reactions such as urticaria and rhinitis.

Adult↗

PubMed2006

Erosive effect of an antihistamine-containing syrup on primary enamel and its reduction by fluoride dentifrice.

AIM: This study evaluated the action of an antihistamine-containing syrup (Claritin D) on enamel that was subsequently submitted or not to applications of fluoride dentifrice. METHODS; Two hundred sixty-four slices (n=44 per subgroup) prepared from exfoliated primary molars were evaluated in hardness tests. Six subgroups were submitted to different treatments for 10 days. The controls underwent pH cycling with (positive control) or without (negative control) three daily immersions in fluoride dentifrice/distilled water slurry. The test subgroups related to daytime use of the antihistamine syrup underwent pH cycling and two 5-min applications of Claritin D, coupled or not to the three daily immersions in the fluoride slurry. The subgroups related to nocturnal use of the syrup were submitted to the same procedures of daytime subgroups, respectively, but with one of the applications of Claritin D lasting for 8 h. RESULTS: The median hardness values obtained after use of the syrup were significantly lower than the initial ones. Equivalent values for subgroups submitted to fluoride applications in addition to treatment with the syrup were significantly higher. CONCLUSION: It was concluded that the antihistamine-containing syrup reduced the hardness of primary enamel and that, in this experiment, the use of fluoride dentifrice was able to diminish this erosive effect.

Cariostatic Agents↗

PubMed1990

Responsiveness of chloroquine-induced pruritus to antihistamine therapy--a clinical survey.

A clinical survey in Benin (Nigeria) has revealed that 393 out of 541 respondents experienced pruritus (itching) whenever they took chloroquine for malaria treatment. The reaction was always severe in 90% of the cases. Based on this experience, the pruritus-prone subjects were subsequently given antihistamine therapy either 30 min before or along with chloroquine administration (initial dose, 600 mg base oral, or 200 mg base i.m.). The success rates obtained with the following antihistamines were 49% (chlorpheniramine maleate, 4-8 mg oral), 46% (mepyramine maleate, 50-100 mg oral), and 60% (Promethazine hydrochloride, 50 mg oral or i.m.). Promethazine appears to be the most effective in the prevention of chloroquine-induced pruritus but the differences were not significant. The antihistamine was more frequently given 30 min before chloroquine, but this had no advantage over the concomitant administration of the two drugs, which may therefore be presented in one dosage form for a better treatment compliance.

Adult↗

PubMed1993

The effect of some commercially available antihistamine and decongestant intra-nasal formulations on ciliary beat frequency.

The effects of azelastine (0.1%) nasal spray (Rhinolast) on ciliary beat frequency are investigated and compared with those of oxymetazoline hydrochloride (Vicks Sinex), xylometazoline (Otrivine) and ephedrine hydrochloride (0.5%). It is shown that all four formulations exert a ciliotoxic effect. The antihistamine (azelastine) and the two long-acting alpha sympathomimetic decongestants (xylometazoline and oxymetazoline) had comparable effects which were milder than those observed with ephedrine, the less specific alpha and beta sympathomimetic agent. The results suggest that the intranasal application of all four products should be restricted to short-term therapy. Oral antihistamine therapy and not topical therapy should still be the first-line therapy for antihistamine-responsive rhinitis until non-ciliotoxic formulations can be developed.

Animals↗

PubMed1960

The anti-anaphylactic and histamine-releasing properties of the antihistamines. Their effect on the mast cells.

IT HAS BEEN SHOWN THAT, DEPENDING UPON THEIR CONCENTRATION, ANTIHISTAMINES ACT IN THREE DIFFERENT WAYS: (a) by competitive inhibition of histamine as already known; (b) by destroying mast cells and releasing histamine; and (c) by preventing mast cell damage and histamine release in anaphylaxis. Furthermore, antihistamines potentiated mast cell damage and histamine release by compound 48/80, when acting on guinea-pig tissues, and inhibited these same phenomena when acting on rat tissues. It is concluded that the effect of antihistamines in anaphylaxis is possibly due both to their competitive inhibition of histamine on smooth muscle receptors and to their inhibition of mast cell damage and histamine release by antigen.

Anaphylaxis↗

PubMedDate not supplied

Antihistamines and their role as antipruritics.

Antihistamines that bind to the histamine 1 receptor (H1) serve as important therapeutic agents to counter the effects of histamine in the skin. Two generations of antihistamines exist; however, second-generation agents are more advantageous because they cause less sedation, have a longer half life and are more selective for the H1 receptor. While H1 antihistamines have proven to be effective at reversing the pruritus and cutaneous lesions of chronic urticaria, their ability to treat pruritus associated with other cutaneous and systemic diseases is unproven.

Antipruritics↗

PubMed2005

Management of seasonal allergic rhinitis: comparative efficacy of the newer-generation prescription antihistamines.

PURPOSE: To discuss the efficacy and safety of second-generation prescription antihistamines, cetirizine, desloratadine, and fexofenadine, and to inform nurse practitioners (NP) who are in a position to optimally manage patients presenting with seasonal allergic rhinitis (SAR). DATA SOURCES: Selected published clinical trials. CONCLUSIONS: NP, who are ideally placed to successfully manage the majority of patients with SAR, should be fully aware of the treatment options available. Although first-generation over-the-counter antihistamines are convenient to use and are readily accessible, patients run the risk of experiencing adverse effects, such as sedation. For this reason, second-generation antihistamines should be considered a better alternative; however, they need to be evaluated individually on the basis of their proven efficacy and safety. Both cetirizine and fexofenadine are equally effective at relieving the symptoms of SAR; however, cetirizine has been shown to be more likely to cause sedation and impairment. IMPLICATIONS FOR PRACTICE: If left untreated, SAR can have a substantial effect on patients' quality of life, resulting in fatigue, irritability, sleep disorders, and cognitive impairment.

Adolescent↗

PubMed1975

The interaction of antihistamines with lecithin monolayers.

The interaction of a series of antihistamines with monolayers of L-alpha-dipalmitoyl lecithin has been examined. An increase in the monolayer surface pressure was noted for monolayers spread on the antihistamine solutions, suggesting penetration of the film by drug molecules. At high surface pressures there was an apparent ejection of drug molecules from the film. The ability of the antihistamines to increase surface pressure was correlated with their surface activity at the air-solution interface. The effect of drug concentration on the magnitude of the surface pressure was examined for diphenhydramine hydrochloride. Application of the Gibbs adsorption equation at low surface compressions indicated an approximate area per molecule for diphenhydramine in the film which was in good agreement with the value previously obtained at the air-solution interface. Preliminary measurements showed that the surface pressure increase was larger in the presence of phosphate buffer at pH 6-8. It was not clear whether this effect was caused by the buffer components or was a pH effect.

Chemical Phenomena↗

PubMed1998

Molecular basis for the lack of HERG K+ channel block-related cardiotoxicity by the H1 receptor blocker cetirizine compared with other second-generation antihistamines.

In the current study, the potential blocking ability of K+ channels encoded by the human ether-a-go-go related gene (HERG) by the piperazine H1 receptor antagonist cetirizine has been examined and compared with that of other second-generation antihistamines (astemizole, terfenadine, and loratadine). Cetirizine was completely devoid of any inhibitory action on HERG K+ channels heterologously expressed in Xenopus laevis oocytes in concentrations up to 30 microM. On the other hand, terfenadine and astemizole effectively blocked HERG K+ channels with nanomolar affinities (the estimated IC50 values were 330 and 480 nM, respectively), whereas loratadine was approximately 300-fold less potent (IC50 approximately 100 microM). In addition, in contrast to terfenadine, cetirizine did not show use-dependent blockade. In SH-SY5Y cells, a human neuroblastoma clone that constitutively expresses K+ currents carried by HERG channels (IHERG), as well as in human embryonic kidney 293 cells stably transfected with HERG cDNA, extracellular perfusion with 3 microM cetirizine did not exert any inhibitory action on IHERG. Astemizole (3 microM), on the other hand, was highly effective. Terfenadine (3 microM) caused a marked (approximately 80%) inhibition of IHERG in SH-SY5Y cells, whereas loratadine, at the same concentration, caused a 40% blockade. Furthermore, the application of cetirizine (3 microM) on the intracellular side of the membrane of HERG-transfected human embryonic kidney 293 cells did not affect IHERG, whereas the same intracellular concentration of astemizole caused a complete block. The results of the current study suggest that second-generation antihistamines display marked differences in their ability to block HERG K+ channels. Cetirizine in particular, which possesses more polar and smaller substituent groups attached to the tertiary amine compared with other antihistamines, lacks HERG-blocking properties, possibly explaining the absence of torsade de pointes ventricular arrhythmias associated with its therapeutical use.

Animals↗

PubMed1984

Effects of two antihistamine drugs on actual driving performance.

A double blind placebo controlled experiment was conducted measuring the effects of the centrally active antihistamine triprolidine and the peripherally acting antihistamine terfenadine on actual driving performance in a group of experienced women drivers. Triprolidine greatly impaired driving behaviour, whereas terfenadine did not. Triprolidine also impaired subjective and objective measures of mood and arousal, and despite an awareness that their driving was impaired while they were taking this agent subjects could not correct their performance. This study suggests that drivers who need antihistamine drugs should avoid those that act centrally.

Arousal↗

PubMed1979

Effect of an inhaled antihistamine (clemastine) as a bronchodilator and as a maintenance treatment in asthma.

Although intravenous chlorpheniramine can cause bronchodilatation, oral and parenteral antihistamines have not proved useful in treating asthma. Inhaled antihistamines may cause throat irritation, but a recent study of the antihistamine, clemastine, showed it to be an effective bronchodilator without irritant effects. We have extended these studies to determine the site of action of inhaled clemastine and to assess its potential usefulness both as a bronchodilator and as a maintenance treatment. Eleven stable asthmatic patients received inhaled clemastine and placebo and the effect was assessed by serial maximum expiratory flow volume (MEFV) curves breathing air and a helium/oxygen (He/O2) mixture. There was no significant improvement in peak flow rates during air breathing after clemastine and no significant difference between the responses to drug and placebo. Minor but significant changes were seen in some flow measurements on the downslope of the MEFV curve during air and He/O2 breathing, and these are tentatively ascribed to a dilating effect of clemastine on peripheral airways where flow is laminar. Subsequent administration of inhaled isoprenaline showed the patients to be still capable of significant bronchodilatation. The addition of clemastine, from a pressurised aerosol, to the patients' therapeutic regimen for two weeks was no more effective than placebo in controlling airflow obstruction, and did not reduce the need for standard bronchodilators. In our patients clemastine was not a clinically useful bronchodilator either acutely or as a maintenance treatment for asthma.

Adult↗

PubMed1996

Effect of loratadine, an H1 antihistamine, on induced cough in non-asthmatic patients with chronic cough.

BACKGROUND: H1 antihistamines have been shown to have an antitussive effect in patients with asthma, postnasal drip, and allergic rhinitis. No study has been performed to determine whether orally administered H1 antihistamines can reduce the number of coughs induced by stimulation of cough receptors in non-asthmatic patients with chronic dry cough. METHODS: The effect of loratadine (10 mg) on the number of coughs induced by ultrasonically nebulised distilled water (UNDW) was examined in 10 patients with nasal disease and in seven patients with unexplained chronic cough using a randomised, double blind crossover method. Eleven normal volunteers were also studied. Each subject inhaled UNDW for one minute, and the numbers of coughs during the one minute inhalation and the 30 seconds following it were counted. RESULTS: There was no difference in the results of pulmonary function tests performed before and one minute after UNDW inhalation for either patients or normal subjects. There was also no significant difference between the results of pulmonary function tests before or after oral administration of loratadine. Loratadine significantly reduced the number of coughs in patients with nasal disease and in those with unexplained chronic cough, but not in normal subjects. CONCLUSIONS: The H1 antihistamine loratadine reduces cough induced by UNDW. The release of histamine may contribute to the chronic cough in patients with unexplained chronic cough or nasal disease.

Adult↗

PubMed1976

Study of the natural antihistamine-like substance in bile in mammals.

A natural antihistamine substance (NAS) present in bile has been investigated. It was found that the antihistamine activity was not due to proteins, lipids, pigments, or amino acids. On ion exchange chromatography and thin-layer chromatography, this activity was associated with bile acids. Many bile acids could, in varying degrees, inhibit this histamine induced guinea pig ileum contraction, desoxycholic acid being the most potent. However NAS activity could be separated from bile acids and their conjugates using a different solvent system. Furthermore, NAS showed a higher antihistamine activity than bile acids. This substance seems to be responsible for 15-20% of the activity of whole bile. The substance has not yet been identified.

Animals↗

PubMed2004

Steady-state brain concentrations of antihistamines in rats: interplay of membrane permeability, P-glycoprotein efflux and plasma protein binding.

The purpose of this study was to measure the in vivo brain distribution of antihistamines and assess the influence of in vitro permeability, P-glycoprotein (Pgp) efflux, and plasma protein binding. Six antihistamines (acrivastine, chlorpheniramine, diphenhydramine doxylamine, fexofenadine, terfenadine) were selected based on previously reported in vitro permeability and Pgp efflux properties and dosed intravenously to steady-state plasma concentrations of 2-10 micromol/l in rats. Plasma and brain concentrations were measured by LC/MS/MS, and protein binding determined by ultrafiltration. Doxylamine, diphenhydramine and chlorpheniramine had brain-to-plasma concentration ratios of 4.34 +/- 1.26, 18.4 +/- 2.35 and 34.0 +/- 9.02, respectively. These drugs had high passive membrane permeability (>310 nm/s), moderate protein binding (71-84%) and were not Pgp substrates; features that yield high CNS penetration. In contrast, acrivastine and fexofenadine had low brain-to-plasma ratios of 0.072 +/- 0.014 and 0.018 + 0.002, consistent with low passive membrane permeability for both compounds (16.2 and 66 nm/s, respectively) and Pgp efflux. Finally, terfenadine had a brain-to-plasma ratio of 2.21 +/- 1.00 even though it underwent Pgp-mediated efflux (in vitro ratio = 2.88). Terfenadine's high passive permeability (285 nm/s) overcame the Pgp-mediated efflux to yield brain-to-plasma ratio >1. The brain-to-unbound plasma ratio was 22-fold higher suggesting that protein binding (96.3% bound) limited terfenadine's brain distribution. In conclusion, passive membrane permeability, Pgp-mediated efflux and/or high plasma protein binding influence the in vivo brain distribution of antihistamine drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗