Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nitroglycerin was administered to eight healthy volunteers in the form of sublingual tablets, oral sustained-release tablets, and an oral solution. Blood samples were collected for measurement of nitroglycerin and its two isomeric glyceryl dinitrate metabolites. Blood pressure and pulse rate were monitored; subjective evaluations of headache, dizziness, facial flushing, skin irritation, and gastrointestinal upset were made. Nitroglycerin itself was virtually undetectable after the solution and tablet preparations; the metabolites were consistently detectable from a few minutes after dosing to 24 h later. Mean total (nitroglycerin plus metabolite) concentrations were comparable in the 15 min following sublingual administration, and the 8 h following tablet administration. The relative bioavailability of the tablets in comparison with the oral solution was 70 per cent based on metabolite concentrations. Nitroglycerin sustained-release tablets appear to exert their beneficial effects in the prolonged prophylaxis of angina through active metabolites.
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PMID:Pharmacokinetics of nitroglycerin and its metabolites after administration of sustained-release tablets. 155 Sep 9

Adenosine (adenine riboside), administered either as the free base or as the 5'-triphosphate (ATP) by rapid intravenous bolus, depresses atrioventricular (AV) nodal conduction, resulting in transient AV block. Adenosine is the active agent and ATP is rapidly converted to adenosine after exogenous administration. By blocking the anterograde AV nodal limb of a re-entrant circuit, adenosine 6 to 12 mg (or ATP 10 to 20 mg) converts almost all episodes of paroxysmal supraventricular tachycardia (PSVT) involving the AV node within 30 seconds of administration. This is at least equivalent in efficacy to verapamil in adults, and superior to lanatoside C in children, with a considerably more rapid onset of action. Furthermore, if a dose of adenosine is ineffective, the exceptionally short plasma half-life of the adenyl nucleosides (less than 10 sec) allows rapid upward dosage titration until PSVT is terminated. Because the induced conduction block primarily affects the AV node, adenosine is a useful diagnostic tool in patients with broad or narrow QRS complex tachycardia; it terminates arrhythmias dependent on the AV node, unmasks other supraventricular mechanisms during transient AV block, but almost always has no effect on ventricular tachycardia. Noncardiac adverse effects, i.e. flushing, dyspnoea and chest pain, may occur during acute arrhythmia termination or diagnosis with adenosine, and arrhythmias may develop; however, these effects are usually transient (lasting less than 1 minute). Adenosine has also been used to induce coronary vasodilation in patients undergoing thallium-201 single photon emission computed tomography (201Tl SPECT), 2-dimensional echocardiography or positron emission tomography to evaluate suspected coronary artery disease. Intravenous infusion of adenosine 140 micrograms/kg/min for 6 minutes was generally associated with only mild adverse effects. These usually resolved within 1 to 2 minutes of discontinuing adenosine, although occasionally patients required aminophylline and/or nitroglycerin (glyceryl trinitrate). Diagnoses based on the results of scintigraphy were of a sensitivity, specificity and predictive accuracy comparable to those achieved with exercise- or dipyridamole-201Tl SPECT. Adenosine is therefore particularly suitable for the diagnosis of tachycardias and the acute management of PSVT involving the AV node in all age groups, without the risks of cardiac arrest and hypotension associated with verapamil. Furthermore, intravenous adenosine infusion may be used to induce coronary vasodilation in patients unable to perform exercise stress tests for 201Tl scintigraphy, and is well tolerated.
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PMID:Adenosine. An evaluation of its use in cardiac diagnostic procedures, and in the treatment of paroxysmal supraventricular tachycardia. 171 62

The purpose of this study was to determine the effect of site of nitroglycerin ointment placement on headache and flushing in healthy subjects. Twenty-six subjects were given two doses of nitroglycerin ointment 3 hr apart in a randomly assigned arm-chest sequence or chest-arm sequence. Subject reports of headache and flushing using the visual analogue scale were recorded. There were no significant differences in headache or flushing based on the site or sequence of placement. Thus, the practice by nurses of routinely teaching patients to vary the site of nitroglycerin ointment placement to minimize side-effects must be questioned.
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PMID:Effect of nitroglycerin ointment placement on headache and flushing in healthy subjects. 191 19

To develop a reliable experimental model of vascular headache, we studied the dose-response relationship between headache and i.v. nitroglycerin (NTG) in 10 healthy subjects. NTG was infused intravenously over periods of 10 min separated by wash-out periods. Doses of 0.25, 0.50, 1.00 and 2.00 micrograms/kg/min were applied successively with one placebo infusion and wash-out period inserted randomly and double blindly. The subjects scored their headache intensity on a scale 0-10. After 1-8 weeks a retest was performed. Nine subjects developed headache already at 0.25 microgram/kg/min, whereas one had no headache at any dose. Headache severity did not increase with doses above 0.5 microgram/kg/min. This ceiling effect was reproducible. The headache was moderate, usually throbbing, bifrontal and not associated with other migrainous features. It reached maximum within 2.5-5.5 min (medians) at various doses and declined rapidly after NTG discontinuation. Wash-out periods of 10-20 min were sufficient. The reproducibility of headache intensity and character was satisfactory in the retest experiment. There were no unpleasant side effects and no visible flushing. Thus blindness was maintained. I.v. NTG is suitable as an experimental headache model. A constant infusion of 0.5 microgram/kg/min will be suitable for studies of arterial diameter, pulsations, blood flow, etc. Comparative studies of sensitivity should use the present infusion schedule but with the two highest doses substituted by 0.06 and 0.125 microgram/kg/min.
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PMID:Intravenous nitroglycerin as an experimental model of vascular headache. Basic characteristics. 250 3

Forty-seven patients with chronic stable angina pectoris entered a thirteen-week open-label study with a transdermal therapeutic system of nitroglycerin in order to evaluate its clinical efficacy, safety, and patient acceptance. In 19 patients, a beta-blocker and in 17 patients a calcium-channel blocker were continued throughout the study period without alteration of their doses. The study consisted of a two-week run-in period and an eleven-week active drug period. Acute titration was done with nitroglycerin patches on the basis of weekly patient diaries on frequency of angina and sublingual nitroglycerin consumption. Overall, reductions in frequency of angina and in nitroglycerin consumption were statistically significant (p less than 0.05). Adverse reactions were common but tolerable. The reported side effects were headache in 32, skin rash in 18, dizziness in 10, palpitation and itching in 9 each, nausea in 7, flushing in 3, and vomiting in 1 patient. In conclusion, the present study demonstrates that individual dose titration with nitroglycerin patches for obtaining significant antianginal effect is essential. The present therapeutic system is convenient to use and well tolerated and had acceptable side effects in our study population.
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PMID:Clinical experience with a transdermal nitroglycerin system. 310 41

Fifty-six patients with cardiac disease participated in a study to determine the effect of site placement on patient reports of headache and flushing after topical nitroglycerin ointment placement. Nitroglycerin was placed on the upper arm, chest, and pelvis in random order. Approximately 30 minutes after application, patients were asked to evaluate their headache and flushing using a visual analogue scale. No significant difference in the severity of side effects was found when the three sites were compared by multivariate analysis of variance with repeated measures. The clinical practice of instructing patients to vary the site placement of nitroglycerin ointment to avoid side effects was not supported.
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PMID:Effect of nitroglycerin ointment placement on the severity of headache and flushing in patients with cardiac disease. 313 14

To compare the clinical efficacy and dose equivalency of standard nifedipine versus a new gastrointestinal therapeutic system (GITS) formulation of nifedipine, 98 patients with chronic stable angina pectoris participated in a 14-week, multicenter, open-label, crossover trial. All patients were administered nifedipine capsules for one month prior to study entry and continued receiving other antianginal, non-calcium blocker medications. Ninety-one patients (93 percent), 80 men and 11 women, mean age 62 +/- 1 years, completed the trial, which included two weeks receiving standard nifedipine followed by 12 weeks receiving nifedipine GITS starting at a dosage equal to the 24-hour total dose of nifedipine capsules and titrated upward as necessary. However, throughout the trial, mean nifedipine dosage was similar on nifedipine GITS compared with standard nifedipine. Angina frequency was significantly less with nifedipine GITS at Weeks 6, 10, and 14 (0.8 episodes/week) compared with baseline with standard nifedipine (1.3 episodes/week, p less than 0.05). Likewise, nitroglycerin consumption was also less at Weeks 6, 10, and 14, but only significantly less at Week 6 (nifedipine 1.2/week versus nifedipine GITS at six weeks, 0.7/week; p less than 0.05). Resting hemodynamic parameters, including systolic and diastolic blood pressure and heart rate, were not significantly different with standard nifedipine versus nifedipine GITS during the 12-week study. Total incidences of side effects were similar for both treatments (standard nifedipine, 16; nifedipine GITS, 17). However, incidence of vasodilator side effects (flushing, dizziness, and light-headedness) was significantly less frequent with nifedipine GITS (standard nifedipine, 12; nifedipine GITS, six; p less than 0.05). Thus, results from this open-label, crossover trial suggest that nifedipine GITS dosing is similar to multidose standard nifedipine with equivalent 24-hour efficacy for nifedipine GITS.
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PMID:Nifedipine gastrointestinal therapeutic system in stable angina pectoris. Results of a multicenter open-label crossover comparison with standard nifedipine. 314 Jun 60

Ocular sympathetic function, facial flushing and the presence or absence of lachrymation and rhinorrhoea were examined in 30 patients during spontaneous or nitroglycerin-induced cluster headache. In 27 cases measurements were also obtained during the headache-free interval. Ocular sympathetic function was impaired on the symptomatic side between cluster attacks and function was reduced further during cluster headache. Greater heat loss from the orbital region on the symptomatic side was associated with ocular sympathetic dysfunction both during and between attacks, and with lachrymation during attacks. Heat loss from the cheek and side of the nose was greater on the symptomatic side in patients whose attack was accompanied by lachrymation, but heat loss from these areas was unrelated to the extent of ocular sympathetic deficit. These findings suggest that parasympathetic overactivity in the greater superficial petrosal nerve provokes facial flushing and lachrymation. Parasympathetic overactivity could also cause dilatation of the internal carotid artery and compression of the periarterial plexus of sympathetic fibres, producing a sympathetic deficit with release of vasoconstrictor tone in the eye. Thus autonomic disturbances in cluster headache may be explained by the unitary hypothesis of parasympathetic hyperactivity being responsible for ocular sympathetic deficit.
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PMID:Autonomic disturbances in cluster headache. 317 90

This study evaluated 1 year the efficacy of therapy with nicardipine in patients with chronic stable angina pectoris. Twenty-five male patients were entered. After a placebo run-in phase, the patients received nicardipine 30 mg, nicardipine 40 mg, and placebo, three times daily given in random, double-blind manner for 8 weeks. A double-blind, cross-over study comparing nicardipine with placebo was then undertaken. After 5 months of open treatment with nicardipine 90 or 120 mg day-1, patients received either placebo or nicardipine for 3 weeks, each followed by the alternative treatment for an additional 3 weeks and further open-label treatment with nicardipine for another 3-5 months. There were no significant changes in the PR, QRS or QT intervals, or in the QRS pattern during the short-term and long-term studies. There were no significant differences in mean heart rate after nicardipine compared with baseline. During treatment with nicardipine 120 mg day-1, patients reported significantly fewer anginal attacks compared with placebo, and nitroglycerin consumption also decreased. Nicardipine increased treadmill time, time to onset of angina, and time to one mm ST segment depression. These effects were maintained after 6 months of continued nicardipine therapy. Adverse effects were minor and well tolerated and included headache, dizziness, gastrointestinal upset, flushing paraesthesia and pedal oedema. Abrupt withdrawal of nicardipine at the end of the study resulted in a rapid return of the original symptoms but without further deterioration from the baseline measurements. Nicardipine was effective in the treatment of stable effort angina pectoris; this benefit was maintained for the entire year of treatment.
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PMID:Short- and long-term treatment of stable effort angina with nicardipine, a new calcium channel blocker: a double-blind, placebo-controlled, randomised, repeated cross-over study. 392 59

Techniques are available to minimize the concentration of asbestos fibers in drinking water. Filtration research conducted at locations on Lake Superior and in the Cascade Mountains in Washington has shown that amphibole and chrysotile fibers can be removed by granular media filtration. Removal percentages can exceed 99% when the raw water is coagulated properly and the filtered water turbidity is 0.10 ntu (nephelometric turbidity units) or lower. Filtered water fiber counts below detectable limits of 0.1 to 0.01 X 10(6) fibers/L can be attained. A study by the Metropolitan Water District of Southern California showed that when raw water chrysotile counts ranged from 200 X 10(6) fibers/L to 2000 X 10(6) fibers/L, filtered water fiber counts frequently exceeded 1 X 10(6) fibers/L. Even so, striving to attain a filtered water turbidity of 0.1 ntu resulted in improved fiber removal. Pilot scale and distribution system research projects have shown that asbestos cement (AC) pipes can be protected from dissolution and leaching effects that can result in release of asbestos fibers into drinking water. Suggested techniques include modifying low pH, low alkalinity waters so they are not aggressive; coating the pipe wall with a chemical precipitate; and applying a cement mortar lining to the pipe wall. Operation and maintenance practices related to the distribution system, when AC water mains are in service, can influence the fiber count in tapwater. Main flushing can stir up sediment that accumulates in low-flow and dead-end areas, raising the fiber count. If mains are tapped and the cuttings are not flushed away through the tapping machine, but are instead permitted to fall into the water main, the fiber count can be raised.
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PMID:Engineering and operating approaches for controlling asbestos fibers in drinking water. 655 30


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