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A simplified premedication protocol for one-hour paclitaxel infusion in various combinations.

BACKGROUND: Many investigations have focused on optimal doses/schedules since regulatory agency approval of paclitaxel (Taxol). Paclitaxel is generally administered at doses of 175-225 mg/m2 over 3 hours or 135-175 mg/m2 over 24 hours, every 3 weeks. The purpose of this study was to simplify administration and render it suitable and practical in the outpatient setting. Using this rationale, the duration of administration was decreased to one hour, with a minimized premedication regimen. MATERIAL/METHODS: One hundred patients who were to receive paclitaxel-based chemotherapy combinations entered the study. Tumor types were non-small-cell lung cancer (NSCLC, n=40), small-cell lung cancer (SCLC, n=18), breast cancer (n=12), head and neck cancer (n=16), and ovarian cancer (n=14). Sixty patients received paclitaxel at 175 mg/m2 and the remaining 40 at 225 mg/m2. The premedication regimen consisted of a single dose of dexamethasone 20 mg, dimethindene maleate (Fenistil) 4 mg, and ranitidine (Zantac) 50 mg, followed by the standard antiemetic therapy. Paclitaxel was always administered before other chemotherapeutic agents, i.e. ifosfamide and/or platinum compounds, except for breast cancer, where epirubicin preceded paclitaxel administration. RESULTS: Hypersensitivity reactions were recorded in 7 patients (7.0%) and were not influenced by age, gender, disease, dose schedule, or cycles of therapy. No serious adverse events were observed. CONCLUSIONS: The simplified administration dose schedule for paclitaxel is safe and accommodates its combination with other cytostatic agents.

Adult↗

Pharmacodynamic dose finding of dimetindene in a sustained release formulation.

A sustained release form of dimetindene (dimethindene maleate, Fenistil, CAS 3614-69-5) was developed based on a micropellet technique. Aim of the study was to evaluate the efficacy and duration of two doses of dimetindene in a sustained release pellet formulation with a standardised grass pollen provacation model (Vienna Challenge Chamber; VCC). The study with 12 grass pollen allergic volunteers--verified by case history, skin prick test (SPT), and radio allergo sorbent test (RAST)--was carried out in a placebo controlled, double blind, cross-over design. 12 h before a 4-h-lasting continuous challenge with permanent 1000 dactylis grass pollen in the VCC, administration of dimetindene (Fenistil R Pellets) in doses of 4 mg, 8 mg or identically appearing placebo was scheduled in three sessions. Nasal flow and resistance, nasal secretion and subjective symptoms were recorded at 15-min intervals during this long-term challenge under reproducible conditions. In comparison to placebo, dimetindene leads to a statistically significant reduction (p < 0.05) of nasal response and clinical symptoms for at least 16 h after treatment. The efficacy of 8 mg dimetindene was pronounced over 4 mg, however, the differences between both active treatments were not statistically significant. Therefore 4 mg dimetindene once a day is the adequate treatment for usual pollinotic disease conditions.

Adult↗

Allergic reactions after systemic administration of glucocorticosteroid therapy.

OBJECTIVE: To describe patients who developed allergic reactions (ie, erythema on their face and body, itching, flushing, drop in blood pressure, respiratory distress, and cold sweats) immediately after intravenous injection of prednisolone hemisuccinate (SoluDecortin H, E Merck, Darmstadt, Germany). SETTING: Academic medical center. RESULTS: Three of 4 patients had a positive reaction to an intracutaneous test with prednisolone hemisuccinate (SoluDecortin H) but no reaction to the additive sodium succinate. The results of the prick test were negative for all patients. Although no specific IgE antibodies were detected in the serum of these patients, allergic reaction was noted in 3 cases, since standardized techniques to detect antibodies in the serum for hydrocortisone acetate (ie, prednisolone) are lacking. One female patient had a cross-reaction to prednisolone and dexamethasone (Fortecortin, E Merck, Darmstadt, Germany). A renewed application of prednisolone hemisuccinate was well tolerated by all patients when histamine1 and histamine2 receptors were blocked with the use of cimetidine hydrochloride, 200 mg twice per day (1-0-1 ampules, Tagamet, SmithKline Beecham Pharmaceuticals, Philadelphia, Pa) and dimethindene maleate, 4 mg twice per day (1-0-1 ampules, Fenistil, Novartis, Munich, Germany); calcium was given for membrane stabilization. CONCLUSIONS: Allergic reactions to glucocorticoid therapy are only occasionally mentioned in the literature. These reactions appear more often when glucocorticoids are applied topically and may lead to dangerous complications in patients if administered systemically. Therefore, when allergic reactions result from glucocorticoid therapy, (immediate-type reactions should be suspect), consider corticosteroid allergy as a differential diagnosis.

Adult↗

Stereochemical studies of chiral H-1 antagonists of histamine: the resolution, chiral analysis, and biological evaluation of four antipodal pairs.

The resolution of the H-1 antihistamines chloropheniramine, dimethindene, carbinoxamine, and mebrophenhydramine is described. The optical purity of antipodal products is investigated by chiral HPLC (use of alpha 1-acid glycoprotein and beta-cyclodextrin columns) and NMR (spectra of beta-cyclodextrin inclusion complexes). Configurational relationships among the group are reviewed and assignments are confirmed and extended by circular dichroism evidence. Affinity constants of antipodal pairs for guinea pig ileum and cerebellum sites, determined by gut bath and binding experiments respectively, are reported together with some in vivo tests in man for central effects. Results are discussed in terms of configurational requirements for activity and variations in antipodal potency ratios within the group.

Animals↗

Influence of peak measurement parameters on the quality of chiral electrophoretic separations.

The effect of nine peak measurement/analysis parameters on chiral capillary electrophoresis (CE), followed by UV detection, was studied. The parameters pertained UV-detection (detection wavelength, reference wavelength, and wavelength bandwidths), signal processing (data acquisition rate, type and amount of filtering) and peak detection (detection threshold and peak width). The influence of these factors on the chiral separation of dimethindene enantiomers was studied at two different concentrations (i.e., at high and low signal-to-noise (S/N) ratio) by the means of experimental designs. The electropherogram characteristics considered were the resolution between the two enantiomers, the peak areas, and the S/N ratio. A D-optimal design was first used as screening design to identify the most critical parameters. Afterwards, a modelling of the different responses as a function of these critical parameters was performed based on the results of a face-centered central composite design. The results showed that the signal-processing parameters should be carefully selected when developing a CE separation since very important variations in the separation, the S/N ratio and the peak area of the substances can occur by setting these parameters at different levels. The detection wavelength should also be carefully chosen for optimal peak area measurement. The role of these parameters becomes more important with decreasing concentration of the analytes (i.e., low S/N ratio). This study showed that the peak measurement/analysis parameters should be optimized as the chemical and physical parameters of a method. They also should always be well specified in order to allow a good transfer of a method from one instrument to another.

Electrophoresis, Capillary↗

Neutrophil adhesion to histamine stimulated cultured endothelial cells is primarily mediated via activation of phospholipase C and nitric oxide synthase isozymes.

OBJECTIVE AND DESIGN: In order to understand the underlying mechanism of histamine stimulated inflammatory responses, histamine receptor subtypes and signal transduction pathways by which histamine mediates the stimulation of neutrophil adhesion to endothelial cells has been studied in vitro. MATERIAL: Human neutrophils and human umbilical vein endothelial cells. TREATMENT: Confluent human endothelial cell layer were incubated with histamine (1 mM), H1, H2 or H3 receptor agonists: fluorophenylhistamine (10 microM), amthamine (10 microm), methylhistamine (10 microM), respectively. Ten minutes prior to histamine (1 mM) stimulation H1, H2 or H3 receptor antagonists (dimethindene, 100 microM; famotidine, 1OO microM, thioperamid 100 microM, respectively) were added. Histamine stimulated signal transduction pathways were inhibited by adding phospholipase C inhibitor 2-nitro-4-carboxyphenyl N,N-diphenylcarbamat (200 microM), adenylate cyclase inhibitor 9-(2 tetrahydrofuryl)adenine (80 microM), nitric oxide synthase isozymes inhibitor S-ethylisothiourea (1 microM) or guanylate cyclase inhibitor (LY 83583; 10 microM). Neutrophil adhesion was monitored at 30, 60, 90, 120, 150, 180 and 210 min. METHODS: Neutrophil adhesion to endothelial cells was quantified by analysing alkaline phosphatase activity. RESULTS: Histamine stimulation of endothelial cells resulted in a biphasic time and concentration dependent pattern of neutrophil adhesion. This pattern of neutrophil adhesion was mimicked by stimulation of endothelial cells with H1 or H2 agonists. Stimulation of endothelial cells with an H3 agonist had no effect on neutrophil binding. Inhibition of phospholipase C (PLC), nitric oxide synthase isozymes (NOS) or guanylate cyclase (GC) resulted in a significant decrease of neutrophil binding to histamine or agonist stimulated endothelial cells. An increase of neutrophil binding to unstimulated or to agonist stimulated endothelial cells was observed during inhibition of adenylate cyclase. CONCLUSIONS: Our results suggest that histamine stimulated neutrophil adhesion is due to H1 and H2 receptor mediated activation of PLC, NOS and GC. Increase of cAMP concentration seems to mediate an inhibitory effect on PMN adhesion to endothelial cells.

Cell Adhesion↗

Histamine in brain--its role in regulation of seizure susceptibility.

The influence of drugs affecting the turnover and levels of histamine in brain and histamine antagonists on pentetrazole (PTZ)-induced and electroconvulsive seizure threshold in mice was studied. A 1.5-2-fold rise in histamine brain concentration (induced by treatment with histidine or metoprine), led to a concomitant increase of PTZ-induced seizure threshold. A histidine decarboxylase inhibitor (brocresine) induced a depletion of brain histamine by about 75% for at least 8 h, the seizure threshold was, however, only reduced at 6 and 8 h after the injection. At shorter intervals, the seizure threshold was substantially increased. Treatment with centrally acting H1 antagonists (dimethindene and promethazine) in non-sedative dosage diminished the PTZ seizure threshold significantly; no changes were seen after treatment with H2 and H3 antagonists (oxmetidine, ranitidine, zolantidine or thioperamide) and a H3 agonist (R-alpha-methylhistamine). The electroconvulsive threshold was hardly influenced. It is concluded that histamine has a certain anticonvulsant effect which is mediated through H1 receptors.

Animals↗

Inhibition by histamine H1 receptor antagonists of endogenous glibenclamide-sensitive K+ channels in follicle-enclosed Xenopus oocytes.

Effects of histamine receptor ligands on the glibenclamide-sensitive K+ currents induced by K+ channel openers, cromakalim and Y-26763, were examined in follicle-enclosed Xenopus oocytes. Histamine H1 receptor antagonists, promethazine, dimethindene and chlorpheniramine all decreased cromakalim-induced K+ currents with IC50 values of 31.5 microM, 29.5 microM and 138 microM, respectively. These compounds also blocked Y-26763-induced K+ currents with comparable IC50 values. Histamine (1 mM) and histamine H2 receptor antagonists, cimetidine (0.5 mM) and ranitidine (1 mM) had little effect on these K+ currents. These results suggest that histamine H1 receptor antagonists inhibit glibenclamide-sensitive K+ currents by a mechanism other than the histamine H1 receptor antagonism. The inhibitory effects might explain, in part, the reported actions of histamine H1 receptor antagonists in ischemia.

Animals↗

Characterization of histamine receptors in the ureter of the dog.

We investigated the effects of histamine on the motility of isolated segments from canine ureters and characterized pharmacologically the histamine receptors involved. We also evaluated the effects of various autacoids (5-HT, carbachol, noradrenaline, thromboxane, prostaglandin F2alpha) on the motility of canine ureters. Histamine as well as the H1 receptor agonist 2-(2-pyridyl)ethylamine elicited a concentration-dependent contraction. This contractile response was antagonized by dimethindene, causing a rightward shift (pA2 8.30) and a reduction of the slope and the maximal effect (pD'2 6.01) of the concentration-response curve. The histamine H2 receptor antagonist cimetidine in a concentration of 10(-5) mol/l was ineffective concerning the concentration-response curve for histamine. After precontraction of the ureter segments (5-HT, carbachol, prostaglandin F2alpha), a concentration-dependent relaxant effect was evaluated in the presence of histamine or the histamine H2 receptor agonist impromidine. The histamine H2 receptor antagonist cimetidine attenuated the relaxant response, causing a rightward shift of the concentration-response curve. All autacoids except thromboxane were capable of increasing contractility in canine ureters. Comparing the absolute contractile force in the presence of prostaglandin F2alpha, 5-HT, carbachol, noradrenaline and potassium, we found that histamine exhibits the most marked effect on this parameter in the canine ureter. It is concluded that there are two types of histamine receptors modulating contractile activity in the canine ureter: histamine H1 receptors, which mediate contraction, and histamine H2 receptors, which mediate relaxation (in the precontracted tissue).

Animals↗

Neuronal soma-dendritic and prejunctional M1-M4 receptors in gastrointestinal and genitourinary smooth muscle.

A variety of neurons in gastrointestinal and genitourinary smooth muscle express muscarinic auto- as well as heteroreceptors. These receptors are found on the soma and dendrites of many cholinergic, sympathetic and NANC neurons and on axon terminals. A given neuron may contain both excitatory and inhibitory presynaptic muscarinic receptors. The subtypes involved are species- and tissue-dependent, and neuronal M1 to M4 receptors have been shown to be expressed in smooth muscle tissues. In this study, the ability of several selective muscarinic receptor antagonists to inhibit the effect of arecaidine propargyl ester (APE) on prejunctional muscarinic receptors on sympathetic nerve endings in the rabbit anococcygeus muscle (RAM) was investigated to characterise the receptor subtype involved. Electrical field stimulation (EFS) resulted in a release of noradrenaline (NA) eliciting monophasic contractions due to stimulation of postjunctional alpha1-adrenoceptors. The selective muscarinic agonist APE did not reduce contractions to exogenous NA, but caused a concentration-related and N-methylatropine-sensitive inhibition of neurogenic responses. All muscarinic antagonists investigated failed to affect the EFS-induced contractions, but shifted the concentration-response curve of APE to the right in a parallel and surmountable fashion. Schild analysis yielded regression lines of unit slope, indicating competitive antagonism. The following rank order of antagonist potencies (pA2 values) was found: tripitramine (9.10) > AQ-RA 741 (8.26) > or = himbacine (8.04) > or = (S)-dimethindene (7.69) > pirenzepine (6.46) > or = p-F-HHSiD (6.27). A comparison of the pA2 values determined in the present study with literature binding and functional affinities obtained at native or recombinant M1 to M5 receptors strongly suggests that NA release from sympathetic nerve endings in RAM is inhibited by activation of prejunctional muscarinic M2 receptors.

Adrenergic alpha-Antagonists↗

A unitary mechanism of calcium antagonist drug action.

[3H]Nitrendipine binding to drug receptor sites associated with calcium channels is allosterically regulated by a diverse group of calcium channel antagonists. Verapamil, D-600 (methoxyverapamil), tiapamil, lidoflazine, flunarizine, cinnarizine, and prenylamine all reduce [3H]nitrendipine binding affinity. By contrast, diltiazem, a benzothiazepine calcium channel antagonist, enhances [3H]nitrendipine binding. All these drug effects involve a single site allosterically linked to the [3H]nitrendipine binding site. Inhibition of [3H]nitrendipine binding by prenylamine, lidoflazine, or tiapamil is reversed by D-600 and diltiazem, which alone respectively slightly reduce or enhance [3H]nitrendipine binding. Diltiazem reverses the inhibition of [3H]nitrendipine binding by D-600. Our prediction that drugs allosterically regulating [3H]nitrendipine binding should be calcium antagonists is confirmed by calcium antagonism in guinea pig ileum observed with the antihistamine dimethindene, the neuroleptics thioridazine and mesoridazine, and the anticholinergic biperiden.

Binding, Competitive↗

Safety of hydroxocobalamin in healthy volunteers in a randomized, placebo-controlled study.

INTRODUCTION: This randomized, double-blind, placebo-controlled, ascending-dose study was conducted in healthy volunteers to evaluate the safety of the investigational cyanide antidote hydroxocobalamin. METHODS: Four ascending dosing groups received intravenous doses of 2.5, 5, 7.5 or 10 g hydroxocobalamin over 7.5 to 30 minutes at a constant infusion rate. Volunteers (n = 136) randomized 3:1 to receive hydroxocobalamin or placebo underwent a 4-day in-house observation after infusion on Day 1 and follow-up visits on Days 8, 15, and 28. RESULTS: The most common drug-related adverse events were asymptomatic and self-limiting chromaturia and reddening of the skin, which are attributed to the red color of hydroxocobalamin. Other adverse events included pustular/papular rash, headache, erythema at the injection site, decrease in lymphocyte percentage, nausea, pruritus, chest discomfort, and dysphagia. Hydroxocobalamin was associated with an increase in blood pressure in some volunteers. Blood pressure changes peaked toward the end of hydroxocobalamin infusion and typically returned to baseline levels by 4 hours postinfusion. Maximum mean changes from baseline in systolic blood pressure ranged from 22.6 to 27.0 mmHg across hydroxocobalamin doses compared with 0.2 to 6.7 mmHg in the corresponding placebo groups. Maximum mean change from baseline in diastolic blood pressure ranged from 14.3 to 25.4 mmHg across hydroxocobalamin doses compared with -3.0 to 3.8 mmHg in the corresponding placebo groups. Two allergic reactions that occurred within minutes after start of the 5- and 10-g hydroxocobalamin infusions were successfully managed with dexamethasone and/or dimethindene maleate. CONCLUSION: Timely intervention for acute cyanide poisoning could entail administration of an antidote in the prehospital setting based on a presumptive diagnosis. Results of this placebo-controlled study in healthy volunteers corroborate previous studies and French postmarketing experience in cyanide-exposed patients in suggesting that the safety profile of hydroxocobalamin is consistent with prehospital or hospital use.

Adolescent↗

A simplified premedication schedule for 1-hour paclitaxel administration.

Many investigations have focused on an optimal dosing schedule for paclitaxel since its regulatory approval. Paclitaxel is generally administered at a dose of 175 mg/m2 IV over 3 hours or 135-175 mg/m2 IV over 24 hours, every 3 weeks. The purpose of this study was to simplify the administration of paclitaxel to make it suitable and practical in the outpatient setting. Using this rationale, the duration of administration was decreased to 1 hour, with a minimized premedication regimen. Fifty-two patients scheduled to receive paclitaxel-based chemotherapy were entered into the study. Tumor types included non-small cell lung cancer, small cell lung cancer, breast cancer, head and neck cancer, and ovarian cancer. Twelve patients received paclitaxel 175 mg/m2 IV, and the remaining 40 patients received paclitaxel 225 mg/m2 IV. Premedication consisted of IV dexamethasone 20 mg over 5-10 minutes, given 30-60 minutes before infusion of paclitaxel,followed by IV dimethindene maleate 4 mg and IV ranitidine 50 mg over 30 minutes. Paclitaxel always was administered before other chemotherapeutic agents. Hypersensitivity reactions were recorded in 4 patients (7.7%) and were not influenced by age, gender, disease, dose schedule, or number of cycles of therapy; no serious hypersensitivity reactions were observed. The present study supports the efficacy and safety of a short premedication schedule; with further study, this schedule might become a standard premedication protocol prior to paclitaxel administration.

Adult↗

[Anti-edema effects of some H1-receptor antagonists].

Experiments carried out with mice of CFLP strain have shown that antihistaminics (chloropyramine, cyproheptadine and dimethindene maleate) significantly inhibit the extents of ear oedema induced by croton oil, dithranol or capsaicin. In rats of Wistar strain, oedema was induced in the hind paw by the subplantar injection of carrageenin, and simultaneously by the application of croton oil to the inner surface on the ear. Preliminary antihistamine treatment inhibited the development of both types of oedema, to statistically significant extent.

Animals↗