A CLINICAL COMPARISON OF THE ANTIPYRETIC POTENCY OF ASPIRIN AND SODIUM SALICYLATE

Comparative analgesic and anti-inflammatory properties of sodium salicylate and acetylsalicylic acid (aspirin) in rheumatoid arthritis

1. Enteric coated sodium salicylate 4.8 g daily was compared with the same dose of enteric coated aspirin in 18 patients with rheumatoid arthritis. 2. After an initial washout period lasting 3 days, patients were randomly allocated to treatment with sodium salicylate or aspirin. After 2 weeks the two treatments were crossed over. 3. Pain relief, reduction in articular index of joint tenderness, increase in grip strength, decrease in digital joint circumference and patients' assessment showed significant improvement with both treatments compared with the washout period. No significant differences were found between the two therapies. 4. No correlation was found in the degree of improvement in any of the clinical outcomes and the salicylate concentrations at steady state.

Ocular distribution of aspirin and salicylate following systematic administration of aspirin to rabbits

The distribution of aspirin and salicylate 30 min after the intravenous administration of different doses of aspirin has been investigated in the rabbit eye. HPLC enabled a rapid and sensitive determination of both substances. A considerable dose-dependent penetration into all ocular tissues was observed with both aspirin and salicylate. Aspirin concentrations were higher than in plasma in all ocular tissues with the exception of the lens. These results show that an unhydrolysed drug may have a direct local effect by acetylating lens protein or other ocular constituents.

Changes in body temperature after administration of antipyretics, LSD, delta 9-THC and related agents: II

Antipyretics, in particular acetaminophen, aspirin and ibuprofen, constitute the single most important class of drugs used therapeutically for an effect on body temperature. Hallucinogens exert prominent actions on the central nervous system, and it is not surprising that, like so many other centrally-acting agents, they too often affect temperature. This compilation primarily covers the considerable amount of data published from 1981 through 1985 on the interactions of these drugs and thermoregulation, but data from many earlier papers not included in a previous compilation are also tabulated. The effects of agents not classically considered as antipyretics on temperatures of febrile subjects are also covered. The information listed includes the species used, the route of administration and dose of drug, the environmental temperature at which experiments were performed, the number of tests, the direction and magnitude of change in body temperature and remarks on special conditions, such as age or brain lesions. Also indicated is the influence of other drugs, such as antagonists, on the response to the primary agent.

Salicylate measurement: clinical usefulness and methodology

The salicylates are the most commonly used analgesic, antipyretic, and anti-inflammatory drugs. They are available in hundreds of preparations, many of which are over-the-counter medications. The easy access to large quantities of the drug and the widespread perception that the drug is harmless have contributed to salicylate intoxication becoming a serious and common problem, particularly among the pediatric and geriatric populations. Salicylate is still the major drug for the treatment of rheumatic diseases. The use of salicylate in high doses for the management of these patients requires close monitoring of serum salicylate levels because of the large interindividual variation in dose-serum level relationships and the narrowness of the therapeutic range. Thus, both for the management of patients intoxicated with salicylate and patients who are on high-dose salicylate therapy, the measurement of serum salicylate levels is an important clinical laboratory service. Recent research on the inhibitory effect of aspirin on platelet aggregation has led to the prophylactic use of aspirin in low doses as an antithrombotic drug. This new therapeutic use of aspirin can be aided by monitoring low serum levels of salicylate and perhaps aspirin itself. This article reviews the current state of the knowledge of the pharmacokinetics and clinical toxicology of salicylate, the clinical usefulness of salicylate measurement by the clinical laboratory, and recent development in the analytical technology for salicylate analysis.

The metabolic rate during the time course of salicylate antipyresis in the rabbit

The processes concerned with the production and loss of body heat in sodium salicylate or acetylsalicylic acid antipyresis were investigated in adult rabbits at an ambient temperature of 21.5 +/- 0.5 degrees C. The experimental fever elicited by i.v. injection of lipopolysaccharide Escherichia coli (1 microgram/kg) was accompanied by increases in O2 consumption and CO2 production as well as decreases in convective heat loss. Pretreatment with 200 mg/kg of sodium salicylate (an hour's i.v. infusion) or with the same dose of acetylsalicylic acid (per os) significantly reduced pyrogen fever but the magnitude of O2 consumption and CO2 production remained at least at the febrile level. In the case of sodium salicylate, the level was even exceeded. At the same time both salicylates activated heat dissipation as manifested by decreases in vasomotor tone and tachypnea. Thus, it is apparent that the antipyretic effect of salicylates may develop without the inhibition of heat production. Heat loss processes initiated by these drugs are responsible for the antipyresis.

Review of the comparative analgesic efficacy of salicylates, acetaminophen, and pyrazolones

Use of salicylates, acetaminophen, and pyrazolones has become increasingly complex, extending from the treatment of acute, mild pain to chronic, moderately severe pain. The intensity, rather than the nature, of the pain determines the efficacy of aspirin. A clinical dose-response relationship has been established, and time-effect curves indicate that the total threshold-raising effect depends on dosage frequency. Contrary to popular belief, aspirin and acetaminophen appear to be equipotent and equianalgesic for the relief of most pain. The combination of aspirin (650 mg) plus codeine (30 mg) is only slightly more effective than aspirin alone. The same holds true for acetaminophen (600 mg) plus codeine (60 mg); the efficacy of the combination is only slightly better than that of acetaminophen alone.

Clinical pharmacokinetics of salicylates: a re-assessment

1 Aspirin is partly hydrolyzed to salicylic acid during absorption. Absorbed aspirin is rapidly hydrolyzed systemically. Salicylic acid elimination kinetics are dependent on drug concentration due to the limited capacity of two major biotransformation pathways: formation of salicyluric acid and of salicylphenolic glucuronide. 2 The time courses of the various pharmacological effects of single doses of aspirin are not directly coincident with the plasma concentrations of either aspirin or salicylic acid but there is reasonably good evidence that the pharmacological effects are related to the concentration of aspirin, salicylic acid, or both. 3 Steady-state plasma salicylate concentrations increase more than proportionally with increasing daily dose; the time required to reach steady state increases with increasing daily dose. Dosage intervals of 8 or even 12 h are usually sufficient to maintain plasma salicylate concentrations in the anti-inflammatory concentration range. Monitoring of plasma salicylate concentrations in this range is facilitated by the relatively small drug concentration fluctuations during a dosing interval at steady-state. 4 Limited data suggest that the pharmacological activity of salicylate is produced by free (unbound) drug. As the plasma protein binding of salicylic acid is concentration-dependent and subject to pronounced interindividual differences, it is preferable, at least in principle, to monitor free rather than total concentrations of salicylate in plasma. Although salicylate concentration in saliva reflects the free rather than total salicylate concentration in plasma or serum, use of saliva for indirect monitoring of plasma salicylate concentrations seems to be impractical for technical reasons.

The effect of salicylates on the hemostatic properties of platelets in man

Ingestion of 1.5 g of aspirin, but not of sodium salicylate, produced a significant prolongation of the bleeding time in six normal male subjects when compared with the effects of a placebo. Similar differences in the effect of the two drugs on platelets was also observed. Aspirin ingestion resulted in impaired platelet aggregation by connective tissue and was associated with a decreased release of platelet adenosine diphosphate (ADP); sodium salicylate had no effect on these values. In vitro, incubation of platelet-rich plasma with an optimum aspirin concentration of 0.50 mmole/liter (0.045 mg/ml) inhibited both the adhesion of platelets to connective tissue and the release of ADP as well as the secondary wave of platelet aggregation produced with ADP or epinephrine; sodium salicylate had no effect on these reactions, which were also normal in patients with von Willebrand's disease. The inhibitory effect produced by ingesting a single 1.8 g dose of aspirin was detectable for 4-7 days at which time salicylate was no longer detectable in the blood, which suggested an irreversible effect on the platelet. Aspirin also inhibited the release of platelet adenosine triphosphate (ATP), but had no effect on the platelet surface charge, available platelet ATP or ADP, or the destruction of ADP by plasma ADPase. These studies lend further support to the hypothesis that ingestion of aspirin, in contrast to sodium salicylate, prolongs the bleeding time by inhibiting the release of platelet ADP, perhaps reflecting the findings in other cell systems which suggest that aspirin alters membrane permeability.