Histamine H1 Antagonists ; pharmacology ; Humans

Chlopheniramine (chlorphenamine) is a racemic antiallergic antihistaminic H1 drug presenting 2 enantioners. The bioequivalence of two sustained-released formulations of racemic chlopheniramine combined with phenylpropanolamine was assessed firstly, in a dissolution test in vitro according to USP requirements. The present work compares in vitro dissolution rates of two formulations of chlopheniramine maleate. The two formulations are equivalent in vitro, both in a water medium or in a SGF/SIF medium. The pH is not a critical parameter affecting drug release and allows to use purified water for chlopheniramine dissolution test
Chlorpheniramine ; Pharmaceutical Preparations ; Histamine H1 Antagonists

Background: Pruritus is a common complication of intrathecal opioids and numerous medications have been used to prevent or treat this complication. However, the efficacy of these medications vary. The choice of medications also depends on the availability and the cost. We performed a randomised double-blind study to evaluate whether nalbuphine is as effective as chlorpheniramine, a medication that is commonly used for treating pruritus for the treatment of intrathecal opioid-induced pruritus in parturients undergoing lower-segment caesarean section. Materials and Methods: Two hundred and thirty four parturients with American Society of Anaesthesiologists (ASA) physical status I or II who had intrathecal opioid-induced pruritus were assigned to receive either intravenous nalbuphine (4 mg eight-hourly) or intravenous chlorpheniramine (5 mg eight-hourly) for a period of 24 hours. Pruritus was assessed using a qualitative scale at pre-treatment, six, nine, 12 and 24 hours post-treatment. Results: The occurrence of intrathecal opioid-induced pruritus was significantly reduced in parturients treated with intravenous nalbuphine as compared to intravenous chlorpheniramine at all intervals studied. Conclusion: In conclusion, nalbuphine is more effective than chlorpheniramine in reducing intrathecal opioid-induced pruritus for parturients undergoing lower-segment caesarean section.
Anesthesia ; Histamine H1 Antagonists ; Injections, Spinal ; Analgesics, Opioid ; Pregnancy

OBJECTIVETo investigate the effects and the mechanisms of the first-generation histamine H(1)-antagonist diphenhydramine and the second-generation histamine H(1)- antagonist fexofenadine on seizure development of pentylenetetrazole (PTZ)-induced kindling in rats.

METHODSThe first-or second-generation histamine H(1)-antagonists and/or histidine were ip injected in rats every 48 h, followed by a subconvulsive dose of PTZ (35 mg/kg). Then the behavioral changes were observed for 30 min after every injection of PTZ. The histamine content of brain was measured spectrofluorometrically.

RESULTCompared with the control group, diphenhydramine (5 mg/kg) significantly augmented the severity of seizure development of PTZ-induced kindling, whereas fexofenadine (5 mg/kg) had no marked influence. The effects of diphenhydramine were antagonized by histidine, the precursor of histamine.

CONCLUSIONSeizure development of PTZ-induced kindling is promoted by the first-but not the second generation histamine H(1)-antagonists via the blockade of brain histamine H(1)-receptor.

Animals ; Histamine ; physiology ; Histamine H1 Antagonists ; pharmacology ; Histamine H1 Antagonists, Non-Sedating ; pharmacology ; Histidine ; pharmacology ; Kindling, Neurologic ; drug effects ; Male ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley ; Seizures ; chemically induced

BACKGROUND: Although oral antihistamines (H1-histamine receptor antagonists) are the main treatment option for pruritus in general skin dermatosis, their effect in treating pruritus of atopic dermatitis (AD) has not yet been established. OBJECTIVE: We conducted a systematic review and meta-analysis to evaluate the effectiveness of combined therapy of H1-antihistamines and topical steroids. METHODS: We systematically searched MEDLINE, Embase, and CENTRAL databases for articles published from 1967 to 2015. We identified 1,206 studies and assessed their titles, abstract, and full-text. Random effects meta-analysis was used to calculate mean differences (MD) with 95% confidence intervals (CI). RESULTS: Two studies satisfying the inclusion criteria of antihistamine therapy with mandatory topical steroid use were selected. Comparing antihistamine monotherapy with combination therapy, patients treated with the addition of antihistamine to topical corticosteroids showed a statistically significant clinical improvement (standard MD, −0.24; 95% CI, −0.42 to −0.05; p=0.01). CONCLUSION: H1-antihistamines may have a synergistic effect when combined with topical steroids by influencing various associative factors of chronic pruritus in AD.
Adrenal Cortex Hormones ; Dermatitis ; Dermatitis, Atopic ; Histamine Antagonists ; Histamine H1 Antagonists ; Humans ; Pruritus ; Skin ; Skin Diseases ; Steroids

We describe a case of a 57 year old female who presented with multiple papules on bilateral extremities with no other systemic findings. Skin lesions consisted of multiple hyperpigmented scaly papules in a rippled pattern some coalescing into plaques. Histologic examination showed deposits of amorphous eosinophilic materials in the papillary dermis. The diagnosis of lichen amyloidosis was made. Treatment with high potency topical steroid in combination with salicylic acid ointment, emollients, and systemic antihistamine which afforded improvement after 2 weeks. There was 90 percent clearance of lesion within 5 months of therapy. The origin and clinical features of papular primary localized cutaneous amyloidosis (PLCA) are reviewed.

Human ; Female ; Middle Aged ; Amyloidosis, Familial ; Dermis ; Emollients ; Histamine Antagonists ; Histamine H1 Antagonists ; Lichens ; Salicylic Acid ; Skin Diseases, Genetic

The present study was carried out to determine the role of histamine H(1) and H(2) receptors in the generation of basic respiratory rhythm. Neonatal (aged 0-3 d) Sprague-Dawley rats of either sex were used. The medulla oblongata slice containing the medial region of the nucleus retrofacialis (mNRF) and the hypoglossal nerve rootlets was prepared and the surgical procedure was performed in the modified Kreb's solution (MKS) with continuous carbogen (95% O(2) and 5% CO(2)), and ended in 3 min. Respiratory rhythmical discharge activity (RRDA) of the rootlets of hypoglossal nerve was recorded by suction electrode. Thirty medulla oblongata slice preparations were divided into 5 groups. In groups I, II and III, histamine (5 μmol/L), H(1) receptor specific antagonist pyrilamine (10 μmol/L) and H(2) receptor specific antagonist cimetidine (5 μmol/L) was added into the perfusion solution for 15 min separately. In group IV, after application of histamine for 15 min, additional pyrilamine was added into the perfusion for another 15 min. In group V, after application of histamine for 15 min, additional cimetidine was added into the perfusion for another 15 min. The discharges of the roots of hypoglossal nerve were recorded. Signals were amplified and band-pass filtered (100-3.3 kHz). Data were sampled (1-10 kHz) and stored in the computer via BL-420 biological signal processing system. Our results showed that histamine significantly decreased the respiratory cycle (RC) and expiratory time (TE), but changes of integral amplitude (IA) and inspiratory time (TI) were not statistically significant. Pyrilamine induced significant increases in RC and TE, but changes of TI and IA were not statistically significant. Cimetidine had no effects on RC, TE, TI and IA of RRDA. The effect of histamine on the respiratory rhythm was reversed by additional application of pyrilamine but not cimetidine. Taken together, with the results mentioned above, histamine H(1) receptors but not H(2) receptors may play an important role in the modulation of RRDA in the medulla oblongata slice preparation of neonatal rats.
Animals ; Animals, Newborn ; Cimetidine ; pharmacology ; Female ; Histamine ; pharmacology ; Histamine H1 Antagonists ; pharmacology ; Histamine H2 Antagonists ; pharmacology ; Hypoglossal Nerve ; physiology ; In Vitro Techniques ; Male ; Medulla Oblongata ; physiology ; Pyrilamine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Histamine H1 ; physiology ; Receptors, Histamine H2 ; physiology ; Respiration

Degranulation of the mast cell has been reported by the injection of histamine liberators and other chemical agents. Chlorpheniramine maleate (1.2mg./kg. and 0.3mg./kg. comprising 1/74and 1/290 of LD50 respectively), which is an antihistamine agent, in physiological saline solution for intravenous injection and in Tyrode solution for intraperitoneal injection were given in single dose. The mesenteric mast cells stained in Pugh solution, as applied by Lee (1968), were counted according to the classification of An (1964) in 4 types; the typical normal mast cell, the Grade I type of mast cell, the Grade II type of mast cell and the Grade III type of mast cell. In the experimental rats given 1.2mg./kg. of chlorpheniramine intravenously, more mesenteric mast cells were s1ightly degranulated than those cells of the rats given 0.3mg./kg. of chlorpheniramine and the control rats. In the experimental rats given 1.2mg./kg. and 0.3 mg./kg. of chlorpheniramine intraperitoneally, more mesenteric mast cells were slightly degranulated than those cells of the control rats. However, in this intraperitoneal study the degree, or severity, of degranulation of the mesenteric mast cell was not in direct proportion to the dosage of this antihistamine. Consequently it is deduced that the experimental dosage of the antihistamine chlorpheniramine maleate, applied 1/74 and l/290 of LD50, caused an evient degranulation of mesenteric mast cells of the albino rats associated with probable histamine liberation.
Animal ; Chlorpheniramine/pharmacology ; Cytoplasmic Granules* ; Female ; Histamine H1 Antagonists/pharmacology* ; Male ; Mast Cells/drug effects* ; Rats

While histamine plays an important role in the pathogenesis of allergic diseases, such as allergic rhinitis, H1-antihistamines, which have been using in the treatment of allergic diseases for more than 70 years, are considered as the cornerstone of the medication of allergic diseases. In this review, we discuss the history of histamine studies and anti-histamine discovery, the histamine receptors, as well as the mechanisms and the safety of H1-antihistamines.
Anti-Allergic Agents ; therapeutic use ; Histamine H1 Antagonists ; therapeutic use ; Humans ; Rhinitis, Allergic, Perennial ; drug therapy

H1-antihistamine is generally a well-tolerated and safe drug. However, in resemblance with all other drugs, H1-antihistamines can also prompt adverse drug reactions (ADRs). We recently encountered the very unusual ADR of H1-antihistamine-induced gynecomastia. A 21-year-old man with idiopathic anaphylaxis was treated with ebastine (Ebastel), a second-generation H1-antihistamine, for the prevention of anaphylaxis. Three months later, the patient remained well without anaphylaxis, but had newly developed gynecomastia. Because anaphylaxis recurred after the cessation of H1-antihistamine, the preventive medication was changed to omalizumab. A few months later, his gynecomastia had entirely disappeared. Physicians should be aware of this exceptional ADR of H1-antihistamine.
Anaphylaxis ; Drug-Related Side Effects and Adverse Reactions ; Gynecomastia ; Histamine H1 Antagonists ; Humans ; Male ; Omalizumab ; Young Adult