Tusal Disease Interactions

Parenteral medications formulated in multidose vials often contain benzyl alcohol as a preservative. Their use is considered by drug manufacturers to be contraindicated in neonates, particularly premature infants and infants of low birth weight. When used in bacteriostatic saline intravascular flush and endotracheal tube lavage solutions, benzyl alcohol has been associated with fatalities and severe respiratory and metabolic complications in low-birth-weight premature infants. Thus, single-dose formulations should always be used in infants whenever possible. However, many experts feel that, in the absence of benzyl alcohol-free equivalents, the amount of the preservative present in these formulations should not necessarily preclude their use if they are clearly indicated. The American Academy of Pediatrics considers benzyl alcohol in low doses (such as when used as a preservative in some medications) to be safe for newborns. However, the administration of high dosages of these medications must take into account the total amount of benzyl alcohol administered. The level at which toxicity may occur is unknown.

Salicylate and its metabolites are eliminated almost entirely by the kidney. Therapy with salicylate drugs should be administered cautiously in patients with renal impairment, especially if it is severe. Reduced dosages may be necessary to avoid drug accumulation. Clinical monitoring of renal function is recommended during prolonged therapy, since the use of salicylate drugs has rarely been associated with renal toxicities, including elevations in serum creatinine, renal papillary necrosis, and acute tubular necrosis with renal failure. Most of the data have been derived from experience with aspirin but may apply to other salicylates as well. In patients with impaired renal function, aspirin has caused reversible and sometimes marked decreases in renal blood flow and glomerular filtration rate. Adverse renal effects have usually reversed rapidly following withdrawal of aspirin therapy.

The use of salicylates, primarily aspirin, in children with varicella infections or influenza-like illnesses has been associated with an increased risk of Reye's syndrome. Although a causal relationship has not been established, the majority of evidence to date seems to support the association. Most authorities, including the American Academy of Pediatrics Committee on Infectious Diseases, recommend avoiding the use of salicylates in children and teenagers with known or suspected varicella or influenza and during presumed outbreaks of influenza. If antipyretic or analgesic therapy is indicated under these circumstances, acetaminophen may be an appropriate alternative. The same precautions should also be observed with related agents such as salicylamide or diflunisal because of their structural and pharmacological similarities to salicylate.

The use of sodium thiosalicylate is contraindicated in patients with thrombocytopenia or coagulation disorders, since intramuscular injections may produce bleeding and hematomas. Patients with a platelet count less than 50,000/mm3 are at an increased risk. The drug is also contraindicated in patients with significant active bleeding or bleeding ulcers. High plasma concentrations of salicylate can interfere with the action of vitamin K and induce a dose-dependent alteration in hepatic synthesis of coagulation factors VII, IX and X. Increases in prothrombin time (PT) may occur. Prolonged therapy with sodium thiosalicylate should be administered cautiously in patients with hypoprothrombinemia, vitamin K deficiency, severe hepatic impairment, or anticoagulant use. Supplementation with vitamin K is recommended.

Like other salicylates, sodium thiosalicylate can cause dose-related gastrointestinal bleeding and mucosal damage, which can lead to development of peptic ulcers, reactivation of latent ulcers, and ulcer perforation. Therapy with sodium thiosalicylate should be considered and administered cautiously in patients with a history of GI disease or alcoholism, particularly if they are elderly and/or debilitated, since such patients may be more susceptible to the GI toxicity of these drugs and seem to tolerate ulceration and bleeding less well than other individuals. Extreme caution and thorough assessment of risks and benefits are warranted in patients with active or recent GI bleeding or lesions. Whenever possible, especially if prolonged use is anticipated, treatment with non-ulcerogenic agents should be attempted first. If sodium thiosalicylate is used, close monitoring for toxicity is recommended. Some adverse GI effects may be minimized by administration with a histamine H2-receptor antagonist or a cytoprotective agent such as misoprostol. Patients with active peptic ulceration or GI bleeding treated with salicylates should generally be administered a concomitant anti-ulcer regimen.

Salicylate and its metabolites are readily removed by hemodialysis and, to a lesser extent, by peritoneal dialysis. Doses should either be scheduled for administration after dialysis or supplemental doses be given after dialysis.

Salicylates, particularly aspirin, may cause or aggravate hemolysis in patients with pyruvate kinase or glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. However, this effect has not been clearly established. Until more data are available, therapy with salicylates should be administered cautiously in patients with G-6-PD deficiency. The same precaution should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate.

The use of salicylates has occasionally been associated with acute, reversible hepatotoxicity, primarily manifested as elevations of serum transaminases, alkaline phosphatase and/or, rarely, bilirubin. Hepatic injury consistent with chronic active hepatitis has also been reported in a few patients, which resulted rarely in encephalopathy or death. Salicylate-induced hepatotoxicity appears to be dependent on serum salicylate concentration (> 25 mg/dL) and has occurred most frequently in patients with juvenile arthritis, active systemic lupus erythematosus, rheumatic fever, or preexisting hepatic impairment. Therapy with salicylates, particularly when given in high dosages, should be administered cautiously in these patients, and periodic monitoring of liver function is recommended. The same precautions should also be observed with the use of related agents such as salicylamide because of their structural and pharmacological similarities to salicylate. A dosage reduction may be necessary if liver function abnormalities develop and serum salicylate concentration exceeds 25 mg/dL, although serum transaminase elevations may sometimes be transient and return to pretreatment values despite continued therapy without dosage adjustment.

Salicylates containing sodium should be avoided or administered cautiously in patients with conditions that may be adversely affected by excessive amounts of sodium, such as congestive heart failure, hypertension, and fluid retention.