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Effects of acetylsalicylic acid and naproxen on the mechanical and biochemical properties of intact skin in rats.

Acetylsalicylic acid, ASA (150 mg/kg/12 h), and naproxen (20 mg/kg/12 h) were administered to young male rats for 9 and 18 days. The doses were set to provide serum concentrations comparable with anti-inflammatory steady state levels in humans. Mechanical tests were performed on skin from the back of the rats. The drugs did not affect the tensile strength of intact skin, nor were differences found in the dry weight or content and concentration of collagen in the skin. However, the rate of collagen synthesis decreased significantly during the study in the ASA treated rats. The naproxen, on the other hand, had no effect. The results may be interpreted as the ASA having an inhibitory effect both on the synthesis and degradation of collagen in skin.

Animals↗

Use of acetylsalicylic acid by physicians and in the community.

OBJECTIVE: To determine physicians' attitudes toward prescribing acetylsalicylic acid (ASA), physicians' own use of ASA and the prevalence of ASA use in the community following the trials of ASA for primary prevention of coronary heart disease. DESIGN: Random sample surveys of physicians and the general public by mail and telephone respectively and a mail survey of a selected panel of expert cardiologists and neurologists. SETTING: London, Ont., and surrounding Middlesex County. PARTICIPANTS: A total of 210 physicians (77% of eligible subjects), including family practitioners and most types of specialists, with an active medical licence and 666 English-speaking people (75% of eligible subjects) aged 18 years or more living in a household with active, listed telephone service. MAIN OUTCOME MEASURE: Long-term ASA use (at least 80 mg on alternate days for 4 or more consecutive weeks) for the treatment of atherosclerosis. MAIN RESULTS: Sampled physicians and experts agreed that long-term ASA therapy was indicated in patients with unstable angina, a transient ischemic episode or recent myocardial infarction but not for primary prevention in healthy middle-aged men and women at low risk for ischemic vascular disease. Both groups were uncertain about the role of ASA in primary prevention in asymptomatic people with risk factors for atherosclerosis. Nine (16%) of the 55 male physicians aged 50 years or more took ASA routinely for primary prevention. In the community survey almost all those who used ASA routinely were 50 years or older. The proportions of men and women in this age group who used ASA routinely for any reason were 19% (95% confidence limits [CLs] 11 and 28) and 14% (95% CLs 8 and 19) respectively; the proportions of men and women who used ASA routinely and apparently for primary prevention were 8% and 1% respectively. A total of 43% (95% CLs 30 and 57) of those with apparent ischemic vascular disease took ASA routinely. Medically unsupervised long-term ASA use for primary or secondary prevention of ischemic vascular disease was uncommon (reported by 2% of those who used the drug routinely). CONCLUSIONS: Physicians generally agree on a role for long-term ASA therapy in the secondary prevention of ischemic vascular disease. However, the prevalence of long-term ASA use in people with overt atherosclerosis in the community may be less than optimal. The role of the drug in the primary prevention of ischemic vascular disease is less accepted. Long-term ASA use in the community for primary prevention is uncommon but detectable.

Adolescent↗

Inhibition of platelet function by a controlled release acetylsalicylic acid formulation--single and chronic dosing studies.

The extent to which a controlled release acetylsalicylic acid (ASA) formulation inhibited platelet function has been evaluated in single and chronic dosing studies. In the single dose study, the platelet inhibitory effect of the controlled release formulation was compared with that of an equivalent dose of soluble ASA and an equimolar dose of sodium salicylate (SA). In the chronic dosing study, ASA dose-response curves for platelet function, including cyclooxygenase activity, were determined for various doses (20-1300 mg) of the controlled release (enteric coated pellets) ASA formulation taken by volunteers daily for one week. Platelet function was assessed by the degree of inhibition of aggregation for several aggregating agents, and the degree of inhibition of activity of platelet cyclooxygenase quantified by the estimation of malondialdehyde (MDA) production. Plasma ASA and SA concentrations were also determined in each study. The controlled release product inhibited platelet function to the same extent as an equimolar dose of soluble ASA, but did so with much lower and sometimes undetectable peak systemic plasma ASA concentrations. SA, the direct metabolite of aspirin, did not have any effect on platelet function. The ASA dose-platelet function response curves obtained from chronic dosing with the controlled release formulation appeared to be similar to those reported previously for the soluble product. The inhibition of platelet function appeared to be unrelated to plasma ASA concentrations.

Adult↗

Effects of acetylsalicylic acid (ASA), ASA plus L-glutamine and L-glutamine on healing of chronic gastric ulcer in the rat.

A chronic gastric ulcer model was produced in rats by the subserosal injection of 20% acetic acid solution (0.015 ml) in order to examine whether (1) acetylsalicylic acid (ASA) irritates the chronic gastric ulcer in active or healed or diminished stage, (2) L-glutamine, given together with ASA, inhibits the adverse effect of ASA. Oral ASA 200 mg/kg/day, given in two divided doses for 10 consecutive days, apparently delayed the healing of the gastric ulcer and irritated the healed ulcer to reulcerate. L-Glutamine, 1,500 mg/kg/day, which was given together with ASA in two divided doses, markedly protected the gastric ulcer both in active and healed stages from the deleterious activity of ASA.

Animals↗

Urinary pH and plasma levels of salicylate after administration of different buffered acetylsalicylic acid formulations.

In a controlled cross-over study comprising eight healthy subjects of effervescent acetylsalicylic acid (ASA) and an experimental ASA formulation were compared with unbuffered ASA and placebo concerning effects on the urinary pH within a dosage interval after 2 days' medication with 3 g ASA daily. The effects on the urinary pH were related to the morning plasma salicylate concentrations observed. Both the buffered formulations significantly increased the median pH of the period studied compared to unbuffered ASA, the effervescent by 1.5 units and the experimental by 0.6 units. Unbuffered ASA significantly decreased the median pH compared to placebo. Those subjects with the most acidic urine during placebo treatment showed the most pronounced pH elevations due to effervescent ASA. The plasma salicylate concentration was significantly lower with the effervescent formulation compared with unbuffered ASA, but there was no statistical difference between the experimental tablet and unbuffered ASA. The variable effects on the urinary pH and the plasma salicylate concentrations induced by the two buffered preparations are explained by the different absorbabilities of the buffering agents included. The results presented are consistent with recommendations not to use bicarbonate-containing ASA formulations continuously when high plasma levels are desirable.

Adult↗

Platelet PGI2-receptor behaviour change after treatment with acetylsalicylic acid in healthy volunteers.

After treatment of human platelet membrane fractions with different concentrations of acetylsalicylic acid (ASA) the Iloprost binding capacity (Bmax) and also the dissociation constant (Kd) of the high-affinity PGI2-receptor increased significantly (p less than 0.01, low-affinity receptor only an increase of Bmax, p less than 0.01), whereas only a significant (p less than 0.05) increase of the Kd of the high-affinity receptor was observed for intact platelets.

Adolescent↗

Effects of acetylsalicylic acid and naproxen on the mechanical properties of intact femora in rats.

The influence of acetylsalicylic acid (ASA) and naproxen on growing bones was studied. Young male rats were used. The drugs were administered via gastric gavage twice a day for 9 or 18 days. Drug doses giving serum concentrations corresponding to ordinary anti-inflammatory steady-state levels in humans were used. There was a drug-related influence on the strength of the growing femur. After 9 days the ultimate bending moment of the distal femoral epiphyseal plate and ultimate torsional moment and stress of the femoral diaphysis increased by about 10% in the rats treated with 150 mg/kg/12 h of ASA as compared with controls. After 18 days there were no differences. The ultimate metaphyseal bending moment of the distal femur was not influenced after 9 days with this dose, but was reduced by about 10% compared with controls after 18 days. Doses of 100 mg/kg/12 h of ASA and 20 mg/kg/12 h of naproxen did not change the bone strength. The doses used were well tolerated and did not influence the bone growth or body weight of the rats. A naproxen dose of 40 mg/kg/12 h was lethal; rats that received this dose succumbed to jejunal perforations. The results indicate that ASA influences the remodeling of normally growing bones.

Animals↗

Acute acetylsalicylic acid poisoning: treatment with forced alkaline diuresis and diuretics.

101 patients were treated for acute acetylsalicylic acid (ASA) poisoning in the Nephrological Unit Trondheim between 1971-1975. On admission 33 of them had a serum salicylic acid (SA) concentration greater than 400 microgram/ml (mean 588 +/- 40 microgram/ml). This group was compared with a group of 11 children less than 5 years old with ASA poisoning and a mean serum SA on admission of 550 +/- 34 microgram/ml. Blood pH on admission was normal or elevated in all patients more than 12 years old (mean 7.43 +/- 0.01), whereas 7 of the 11 children suffered from metabolic acidosis. The results of forced alkaline diuresis produced by loop diuretics (bumetanide, furosemide) in ASA poisoned patients older than 12 years are reported. The mean T 1/2 of SA was 9.6 h in the treated group as compared to 18-22 h in untreated patients. There was no apparent difference between the diuretic effect of bumetanide and furosemide.

Acid-Base Equilibrium↗

Increased urinary excretion of the histamine metabolite N tau-methylhistamine during acetylsalicylic acid provocation in chronic urticaria patients.

Seventeen chronic urticaria patients with a history suggestive of acetylsalicylic acid (ASA, Aspirin)-intolerance were challenged with ASA; only 2 patients showed marked clinical reactions. These clinical reactions were accompanied by a significant increase in the urinary excretion of the most important histamine metabolite, N tau-methylhistamine, in comparison with 15 non-responders (p less than or equal to 0.05) and placebo test. These results suggest an involvement of histamine in the pathogenesis of ASA-intolerance in chronic urticaria patients.

Adult↗

Effects of acetylsalicylic acid on the phagocytic function of human polymorphonuclear leukocytes in vitro.

1. In this paper acetylsalicylic acid (aspirin), an anti inflammatory drug, was studied in vitro at doses of 50, 100, 200 and 500 mg/l to see its effects on adherence, chemotaxis, spontaneous mobility, phagocytosis, candidicide power, nitrobule tetrazolium (NBT) reduction as well as the incorporation and metabolism of arachidonic acid in human polymorphonuclear neutrophils (PMNns). 2. Aspirin significantly stimulated neutrophil adherence to nylon fiber at all the doses used, with a correlation between the doses used and the adherence indices found. 3. At the therapeutic dose (100 mg/l) aspirin brings about a significant increase of chemotaxis, but reduces this property at the highest dose (500 mg/l). On the other hand, spontaneous mobility is not altered except with the 500 mg/l dose of aspirin which produces a significative decrease. 4. The ingestion of Cándida albicans by PMNns is significant at the therapeutic dose; the candidicide power is not modified with any of the doses used with 100 mg/l of aspirin nitroblue tetrazolium (NBT) reduction is significantly increased. 5. No changes are observed in the incorporation of arachidonic acid or in the release of its metabolites.

Arachidonic Acid↗

The effect of acetylsalicylic acid on orthodontic tooth movement in the guinea pig.

This study examined the influence of acetylsalicylic acid an inhibitor of prostaglandin synthesis, on orthodontic tooth movement induced with light spring forces in the guinea pig. The animal model was shown to permit reliable and accurate recording of tooth movement up to 28 days. Tooth movement was found to be highly correlated with spring forces, indicating that the model provided a sensitive test of the effect of aspirin on tooth movement. Aspirin was administered orally at the rate of 65 mg/kg per day in three divided doses and was found to effectively inhibit prostaglandin synthesis at the level of the bronchioles. However, aspirin did not appear to significantly affect tooth movement. Thus prostaglandins may not be the only mediators of the bone resorption associated with tooth movement induced by light orthodontic forces under these experimental conditions.

Analysis of Variance↗

Mixture toxicity of the anti-inflammatory drugs diclofenac, ibuprofen, naproxen, and acetylsalicylic acid.

The ecotoxicity of the nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac, ibuprofen, naproxen, and acetylsalicylic acid (ASA) has been evaluated using acute Daphnia and algal tests. Toxicities were relatively low, with half-maximal effective concentration (EC50) values obtained using Daphnia in the range from 68 to 166 mg L(-1) and from 72 to 626 mg L(-1) in the algal test. Acute effects of these substances seem to be quite improbable. The quantitative structure-activity relationships (QSAR) approach showed that all substances act by nonpolar narcosis; thus, the higher the n-octanol/water partitioning coefficient (log Kow) of the substances, the higher is their toxicity. Mixture toxicity of the compounds could be accurately predicted using the concept of concentration addition. Toxicity of the mixture was considerable, even at concentrations at which the single substances showed no or only very slight effects, with some deviations in the Daphnia test, which could be explained by incompatibility of the very steep dose-response curves and the probit analysis of the data. Because pharmaceuticals in the aquatic environment occur usually as mixtures, an accurate prediction of the mixture toxicity is indispensable for environmental risk assessment.

Animals↗

Assay of effervescent tablets by near-infrared spectroscopy in transmittance and reflectance mode: acetylsalicylic acid in mono and combination formulations.

Near-infrared spectroscopy (NIRS) was used to determine acetylsalicylic acid (ASA) in three different effervescent tablet formulations. The nominal ASA concentrations were 14.9% in the single substance formulation (ASA Mono), 17.4% in the combination with ascorbic acid (ASA + C) and 8.7% in the combination with paracetamol and ascorbic acid (ASA Combi). In each case the tablet matrix was composed of seven excipients typical of effervescent tablets. All three formulations were measured as intact tablets in diffuse transmittance and reflectance and as powdered tablets in diffuse reflectance. Calibration was carried out by partial least square (PLS) regression of second derivative spectra. High-performance liquid chromatography (HPLC) was used as the reference method. The relative standard errors of calibration (RSEC) achieved for the three NIR methods were between 1.20 and 2.01% for ASA Mono, between 1.91 and 2.21% for ASA + C and between 2.41 and 4.50% for ASA Combi. The results obtained in transmittance mode were comparable with those obtained in reflectance mode, which is normally used in NIRS. In the test sets of ASA Mono and ASA + C relative root mean square (RRMS) values between 2.21 and 3.13% were obtained. The three NIR methods applied are thus suitable for the quantitative determination of ASA in effervescent tablets and have the advantage over HPLC of being rapid and simply carried out with little sample preparation; they are nondestructive and do not require any environmentally harmful reagents.

Acetaminophen↗

A comparison of choline magnesium trisalicylate and acetylsalicylic acid in patients with rheumatoid arthritis.

Choline magnesium trisalicylate (3.0 g/day) and enteric-coated acetylsalicylic acid (3.0 g/day) have been compared in a double-blind, crossover study on 19 patients with rheumatoid arthritis using the double-dummy technique. Patients were allocated to receive 3-weeks' treatment with each trial drug in random sequence and were assessed at Weeks-1, 0, 3 and 6. Apart from an unexplained significant improvement in grip strength (p less than 0.01) that occurred in patients on choline magnesium trisalicylate when this followed aspirin but not when it preceded it, there was no significant clinical difference between treatments in any of the clinical parameters of improvement that were measured. There was also no clear difference in the side-effects profile produced by the two drugs, but the number of patients recruited to this study was small.

Adolescent↗

Clinical valproate toxicity induced by acetylsalicylic acid.

We report three patients with serious clinical valproate (VPA) toxicity induced by interaction with acetylsalicylic acid (ASA). Two patients had a documented rise in VPA free level, and the third showed only clinical signs of toxicity. Symptoms resolved in all three when the ASA was stopped. This interaction has been previously documented under experimental conditions, and is due to displacement of VPA from plasma protein binding sites and a probable interference in metabolism. This is the first report of the clinical significance of this interaction.

Adolescent↗

Does sucralfate reduce acetylsalicylic-acid-induced gastric mucosal bleeding?

We studied the possible protection of sucralfate with regard to acetylsalicylic acid (ASA)-induced gastric mucosal bleeding as measured by a radiochromium assay of faecal blood loss in a double-blind crossover study involving 16 healthy male volunteers. Medication was given in two combinations during the 2nd and 5th week of the study: 1 g ASA and 1 g sucralfate four times daily, or 1 g ASA four times daily and placebo tablets. Mean faecal blood loss (+/- SEM) was 0.38 +/- 0.04 ml/day in the 1st week (no drugs administered), 7.17 +/- 1.60 ml/day during treatment with ASA + sucralfate, and 9.59 +/- 1.76 ml/day during treatment with ASA + placebo, the difference being not statistically significant. Individual bleeding values registered during sucralfate treatment correlated with those measured in the placebo period. However, three persons with pronounced bleeding after ASA + placebo had minimal bleeding after ASA + sucralfate. Sucralfate may have a protective potential by reducing ASA-induced gastric mucosal bleeding, but further studies are required to evaluate its protective mechanisms and to identify the groups of patients that could benefit from this.

Adult↗

Effect of low and ultra low oral doses of acetylsalicylic acid in microvascular surgery. An experimental study in the rabbit.

About 10 h after administering acetylsalicylic acid (ASA) orally in doses of 4 mg and 20 micrograms/kg b.w., the central arteries of rabbit ears were subjected to severe vascular trauma (arteriotomy/intimectomy). Bleeding times from the trauma regions at reperfusion were measured and the activities from accumulating 32P-labelled homologous platelets recorded until 2 h after reperfusion when patencies were determined. In other studies, the effects of ASA on ex vivo platelet aggregation (aggregometry), thromboxane production, euglobulin clot lysis time and bleeding time following arterial puncture were investigated. Relative to controls, the following parameters were changed: patency was increased, as were the bleeding times following arterial puncture and thromboxane production was reduced. The median values of platelet accumulation were lower, but the changes were not statistically significant. Aggregometry showed decreased rates of platelet aggregability following treatment with ASA 4 mg/kg.

Administration, Oral↗

In the dose range of 0.5-2.0 mg/kg, acetylsalicylic acid does not affect prostacyclin production in hypertensive pregnancies.

OBJECTIVE: To determine the dose of acetylsalicylic acid (ASA), that inhibits the production of the vasoconstrictive, aggregatory thromboxane A2 while sparing the production of the vasodilatory antiaggregatory prostacyclin. DESIGN: A controlled study comparing the effects of three doses of ASA on the production of thromboxane A2 and prostacyclin. METHODS: Seven pregnant hypertensive patients and five non-pregnant healthy women received 0.5, 1.0 and 2.0 mg/kg/day of ASA, each dose for 10-12 days, the treatment periods following each other immediately. Seven normotensive pregnant women served as controls and were given no ASA. Blood and urine samples were taken at baseline and after the treatment periods to determine serum thromboxane B2 and the urinary 2.3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxaneB2, the major stable metabolites of prostacyclin and thromboxane A2, respectively. RESULTS: The urinary excretion of 11-dehydrothromboxaneB2 was significantly higher in both hypertensive (34.9+/-18.3 pg/micromol creatinine) and normotensive (39.3+/-14.4 pg/micromol creatinine) pregnant women than in non-pregnant women (14.8+/-6.4 pg/micromol creatinine). The urinary excretion of 2.3-dinor-6-ketoprostaglandinF1alpha was also higher in normotensive pregnant women (93.9+/-50.9 pg/micromol creatinine) than in non-pregnant women (18.2+/-11.3 pg/micromol creatinine). The excretion rate of 2.3-dinor-6-ketoprostaglandinF1alpha in hypertensive patients was lower than in normotensive pregnant women (44.7+/-24.2 pg/micromol creatinine). At baseline the urinary 2.3-dinor-6-ketoprostaglandin F1alpha/11-dehydrothromboxaneB2 ratio was almost the same in the hypertensive patients (1.6) and in the non-pregnant women (1.2). The ratio was 2.6 in normotensive pregnant women. In the hypertensive group, already the lowest dose of ASA inhibited urinary 11-dehydrothromboxaneB2 excretion significantly. Because none of the doses of ASA inhibited 2.3-dinor-6-ketoprostaglandinF1alpha production, the 2.3-dinor-6-ketoprostaglandinF1alpha/11-dehydrothromboxaneB2 ratio was shifted in the favor of prostacyclin at all dose levels. In the non-pregnant women, even the highest dose level of ASA failed to affect the ratio. CONCLUSION: In the dose range of 0.5-2.0 mg/kg/day, ASA has a favorable effect on the ratio of prostacyclin to thromboxane A2 in hypertensive pregnancies.

Aspirin↗