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"Properties of the active metabolite of this drug are given.

'Not recommended for those with severe renal and hepatic disease. E, enterohepatic cycling;F, extensive first pass metabolism;h, dosage adjustment may be necessary in patients with hepatic impairment;H, dosage adjustment recommended for patients with hepatic impairment; R, dosage adjustment necessary for patients with renal impairment.

"Properties of the active metabolite of this drug are given.

'Not recommended for those with severe renal and hepatic disease. E, enterohepatic cycling;F, extensive first pass metabolism;h, dosage adjustment may be necessary in patients with hepatic impairment;H, dosage adjustment recommended for patients with hepatic impairment; R, dosage adjustment necessary for patients with renal impairment.

Among the salicylates, aspirin and sodium salicylate are by far the most commonly used.

The salicylates are useful in the treatment of minor musculoskeletal disorders such as bursitis, synovitis, tendinitis, myositis, and myalgia. They may also be used to relieve fever and headache. They can be used in the treatment of inflammatory disease, such as acute rheumatic fever, rheumatoid arthritis, osteoarthritis, and certain rheumatoid variants, such as ankylosing spondylitis, Reiter's syndrome, and psoriatic arthritis. However, other NSAIDs are usually favored for the treatment of these chronic conditions because of their lower incidence of GI side effects. Aspirin is used in the treatment and prophylaxis of myocardial infarction and ischemic stroke.

Basic Pharmacology

Aspirin is available as capsules, tablets, enteric-coated tablets (Ecotrin), timed-release tablets (ZORprin), buffered tablets (Ascriptin, Bufferin), and as rectal suppositories. Sodium salicylate is available generically. Other salicylates include choline salicylate (Arthropan), choline magnesium trisalicylate (Trilisate), and magnesium salicylate (Momentum).

Although aspirin itself is pharmacologically active, it is rapidly hydrolyzed to salicylic acid after its absorption, and it is the salicylate anion that accounts for most of the anti-inflammatory activity of the drug. The superior analgesic activity of aspirin compared with sodium salicylate implies that aspirin has an intrinsic activity that is not totally explainable by its conversion to salicylic acid. Aspirin inhibits COX-1 to a much greater extent than COX-2; sodium salicylate is more selective for COX-1. This, combined with the ability of aspirin to acetylate proteins, might account for some of the therapeutic and toxicological differences between aspirin and the other salicylates.

The binding of salicylic acid to plasma proteins varies with its plasma concentrations. At serum salicylic acid concentrations of less than 100 ^g/mL, 90 to 95% is protein bound; at 100 to 400 ^g/mL, 70 to 85% is protein bound; and at concentrations greater than 400 ^g/mL, 20 to 60% is protein bound. The plasma concentration of salicylate that is associated with antiinflammatory activity (200-300 ng/mL) is about six times that needed to produce analgesia. At these higher concentrations, salicylate metabolism is reduced, resulting in a longer half-life for the drug. This reaction is a consequence of the saturable enzyme systems that metabolize salicylates. The plasma half-life for salicylate has been estimated to be 3 to 6 hours at the lower (analgesic) dosage and 15 to 30 hours at the higher (anti-inflammatory) dosages. The rate of hydrolysis of aspirin to salicylic acid is not dose limited, and no differences in the absorption of aspirin have been observed between arthritic patients and normal individuals.

Adverse Effects

The most common adverse effects produced by the salicylates are GI disturbances. Occult blood loss from the GI tract, peptic ulceration, and rarely, severe GI hemorrhage can occur. Because salicylic acid is highly bound to plasma proteins, it may be displaced by other highly protein-bound drugs such as oral anticoagulants, sulfonylureas, phenytoin, penicillins, and sulfonamides. The nonacetylated salicylates have greatly reduced effects on blood loss and produce fewer adverse GI effects. In addition, they may be somewhat kidney sparing. Salicylates may provoke hypersensitivity reactions and prolonged bleeding time in some individuals. Tinnitus, hearing impairment, blurred vision, and light-headedness are indicators of toxic dosages. The use of aspirin in conjunction with any other NSAID is not recommended because of the lack of evidence that such combinations increase efficacy and because of the increased potential for an adverse reaction. Salicylates are contraindicated in children with febrile viral illnesses because of a possible increased risk of Reye's syndrome.

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Arthritis Joint Pain

Arthritis Joint Pain

Arthritis is a general term which is commonly associated with a number of painful conditions affecting the joints and bones. The term arthritis literally translates to joint inflammation.

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