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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reddening of the ears of guinea pigs following the administration of nicotinic acid and its derivatives is regarded as an animal experiment for the human flush-reaction. In agreement with the observations in humans we found that the reddening effects decreased after repeated administration of xantinol nicotinate (Complamin). The results demonstrate that the reddening of the ears of guinea pigs--and presumably flushing in humans as well--is a complex event. The liberation of prostaglandins, histamine and serotonin, and first of all, cholinergic reactions, seem to be involved.
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PMID:[Elucidation of the mechanism of nicotinic acid flush in the animal experiment (author's transl)]. 2 99

Flush is a common side effect of nicotinic acid therapy in patients. The effect is present as long as the level of nicotinic acid increases in the plasma. The mechanism of flush after nicotinic acid has been studied in the ears of guinea-pigs in vivo. The threshold dose of nicotinic acid (1-3 mg/kg) to raise the skin temperature of the ears and to increase the cyclic AMP level of this tissue was similar. Indomethacin and acetylsalicylic acid which inhibit the synthesis of prostaglandins markedly reduce the duration and intensity of the flush. In isolated slices from guinea-pig ears, nicotinic acid increased the level of cyclic AMP; this effect was inhibited by indomethacin. The stimulating action of prostaglandin E1 on the cyclic AMP level of the ear slices was not inhibited by indomethacin. Since administration to man of both cyclic AMP and prostaglandin E1 produces flush it is suggested that nicotinic acid may induce flush by the formation of some prostaglandin which then increases the formation of cyclic AMP.
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PMID:Studies on the mechanism of flush induced by nicotinic acid. 19 86

Seven patients with hyperlipoproteinemia (HLP) type II (four patients with type II A and three patients with type II B), who were experienced to be resistant to hypolipidemic drugs, were treated for 6 months with etofibrate, a double-ester of nicotinic acid and clofibrinic acid, at a dose of 0.3 g t.i.d. Mean serum cholesterol level decreased by up to 18% from a pre-treatment value of 7.7 +/- 1.4 mmol/l. The reduction of serum cholesterol was due both to a decrease in very low density (VLDL) and low density (LDL) lipoprotein cholesteral by 61 and 25%, respectively (after 6 months). Furthermore alpha-LP (HDL) cholesterol increased by 8%, (after 6 months). All seven patients had previously received clofibrate and had obtained a mean decrease in plasma cholesterol by 6%. There was a slight transient increase in S-ASAT and S-ALAT simultaneous with in increase in serum urate. However, these values returned after 3 months to pre-treatment level. No influence on glucose tolerance was recorded. There were no bothersome side effects except a transient discomfort in the form of flushing or acid indigestion which occurred after 1--2 months of treatment with etofibrate.
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PMID:Treatment of hyperlipoproteinemia type II with etofibrate. 52 96

Oral administration of niacin (nicotinic acid) at pharmacologic doses that reduce serum cholesterol levels induces intense flushing in humans. We have recently shown that the vasodilation following ingestion of niacin is due to the release of prostaglandin (PG) D2. However, the site from which PGD2 is released is not known. It has previously been shown that topical application of methylnicotinate causes local cutaneous erythema. Thus, we investigated whether topical methylnicotinate causes a release of PGD2 locally from skin and the possibility that skin may be a major contributor to the release of PGD2 when niacin is administered by mouth. Topical administration of methylnicotinate (10(-1) M) to the forearms of human volunteers resulted in 58- to 122-times increases in levels of PGD2 and 25- to 33-times increases in levels of the metabolite of PGD2, 9 alpha,11 beta-PGF2, in blood drawn from the antecubital vein draining the treated sites. Increased levels of PGD2 and 9 alpha,11 beta-PGF2 were not found in blood drawn simultaneously from veins in the contralateral arm, indicating that the PGD2 was released from the site of methylnicotinate application. The release of PGD2 in response to topically applied methylnicotinate occurred in a dose-dependent manner over the concentration range of 10(-3) to 10(-1) M. The release of PGD2 was not accompanied by a release of histamine, suggesting that the release of PGD2 was not from the mast cell. Following oral ingestion of niacin, levels of PGD2 in superficial venous blood draining the skin were 14 to 1200 times higher than the level in arterial blood supplying the skin of the same arm. This finding indicates that the skin is a major site from which PGD2 is released following oral ingestion of niacin. These studies thus indicate that the cutaneous vasodilation that occurs following oral administration of niacin is primarily due to a release of PGD2 from a niacin responsive cell that resides in the skin.
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PMID:Identification of skin as a major site of prostaglandin D2 release following oral administration of niacin in humans. 137 50

The side effect profiles and lipid lowering efficacy of nicotinic acid (1 g three times daily) and its analogue acipimox (250 mg three times daily) in type 2b hyperlipidaemia were compared in a double-blind placebo controlled study. In the nicotinic acid group (n = 7) at 12 weeks there were significant reductions (P less than 0.05) with respect to placebo (n = 9) in total cholesterol (median and range) 6.6 mmol l-1 (4.8-8.4) vs 8.8 mmol l-1 (7.5-9.5), triglyceride 1.4 mmol l-1 (0.5-4.6) vs 2.8 mmol l-1 (1.5-9.5) and apoprotein B 88.6 mg dl-1 (62.1-114) vs 121.9 mg dl-1 (88.0-170.7). In contrast there was no significant alteration in lipids in the acipimox group (n = 12). Nicotinic acid was associated with a high incidence of side effects, principally cutaneous flushing, while acipimox was well tolerated by all patients.
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PMID:A comparison of acipimox and nicotinic acid in type 2b hyperlipidaemia. 157 71

Niacin (nicotinic acid) is a widely used agent in the treatment of hyperlipidemias characterized by elevated low-density lipoprotein and very-low-density lipoprotein. The tendency of the conventional crystalline niacin to cause flushing has limited its use in many patients. Sustained-release (SR) niacin preparations are increasingly utilized due to a lower incidence of flushing and convenient dosing frequency. Although gastrointestinal and hepatotoxic side effects are common to both formulations, they are more frequent and occasionally more severe with the SR preparations. We describe a patient who developed an acute illness characterized by hypothermia, hypotension, metabolic acidosis, and severe hepatic dysfunction 2 days after substitution of an SR preparation for a previously well-tolerated crystalline niacin.
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PMID:Hepatotoxicity associated with sustained-release niacin. 162 57

Niacin (nicotinic acid) is used frequently in the treatment of hypercholesteremia. It is available in both unmodified and time-release preparations. The latter were developed in attempts to minimize the skin-flushing reaction that affects virtually all users and may limit acceptance. Adverse effects on the liver from both unmodified and time-release preparations have been recognized for many years. We reviewed the literature on the hepatic toxicity of both types of niacin preparations. Adverse reactions in six patients resulted from the exclusive use of unmodified niacin and in two patients from the exclusive use of time-release preparations. In 10 additional patients, adverse reactions developed after an abrupt change from unmodified to time-release preparations. Many of these patients were ingesting time-release niacin at doses well above the usual therapeutic doses currently recommended. Signs of liver toxicity developed in less than 7 days in four of these 10 patients. In doses that achieve equivalent reductions in serum lipids, hepatic toxicity occurred more frequently with time-release preparations than with unmodified preparations. An awareness of toxicity associated with ingestion of high doses of time-release niacin preparations is important because of their widespread availability and the potential for self-prescribed, unmonitored use.
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PMID:Hepatic toxicity of unmodified and time-release preparations of niacin. 173 14

The mechanism of tolerance to nicotinic acid flushing was determined in subjects during a 5-day course of treatment. Objective measures of skin blood flow were used to confirm the development of tolerance. Plasma levels of nicotinic acid showed marked intraindividual variability but were not decreased with the development of tolerance. However plasma levels of 9-alpha 11-beta prostaglandin F2, a stable metabolite of prostaglandin D2, became undetectable in most subjects with the development of tolerance. Thus tolerance is not associated with decreased levels of nicotinic acid or development of tolerance to the prostaglandin mediator, but with decreased levels of the mediator.
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PMID:Tolerance to nicotinic acid flushing. 185 54

1. The bioavailability of three nicotinic acid formulations was investigated in a randomized cross-over study. 2. Single doses of nicotinic acid (500 mg) were given to seven healthy volunteers. The concentrations of nicotinic acid and its main metabolite nicotinuric acid were measured in serum up to 8 h and in urine up to 24 h. 3. The relative bioavailability of unchanged nicotinic acid from two slow release formulations compared with a rapid-release form was only 1% and 25%, respectively. Relative values of AUC (0.8 h) for nicotinuric acid were 15% and 58%, and relative urinary recoveries were 18% and 59%, respectively. Facial flushing was less when slow release formulations were used. 4. The bioavailability of unchanged nicotinic acid is low and the ratio of nicotinuric acid to nicotinic acid in serum and urine is high when slow release formulations are used.
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PMID:The bioavailability of sustained release nicotinic acid formulations. 195 42

The blood flow in the skin and the urinary excretion of the PGI2 metabolite 2,3-dinor-6-keto-PGF1a (PGI-M) were determined in the nine healthy subjects randomly assigned to double-blind oral treatment with a) placebo and acipimox (AC) 500 mg, b) acetylsalicylic acid 1500 mg and AC 500 mg, or c) placebo and nicotinic acid (NIC) 500 mg, on three different occasions. After treatment with placebo and AC there was a transient increase in the skin blood flow, up to about four-times the basal level, and a concomitant increase in skin temperature. After acetylsalicylic acid and AC no increase in skin flow rate or temperature was found. Urinary excretion of PGI-M was insignificantly increased by AC, but fell after acetylsalicylic acid pretreatment. NIC elicited a more marked increase in skin blood flow than AC, and in parallel the urinary excretion of PGI-M was more than doubled. It is concluded that cutaneous flushing induced by AC is cyclo-oxygenase dependent. In comparison to NIC, however, AC appears as a weak stimulant of vascular prostacyclin formation.
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PMID:Acipimox stimulates skin blood flow by a cyclo-oxygenase-dependent mechanism. 212 38


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