Salicylates can produce changes in the thyroid function tests. ASA has been found to delay parturition in rats. This effect has also been described with nonsteroidal anti-inflammatory agents which inhibit prostaglandin synthesis. Because of possible adverse effects on the neonate and the potential for increased maternal blood loss, ASA should be avoided during the last 3 months of pregnancy. Although a direct causal relationship has not been established, it is recommended that salicylates be avoided when possible in children, teenagers and young adults with influenza or varicella until the nature of the possible association between ASA and Reye's Syndrome has been clarified.
Salicylates increase the effects of oral anticoagulants.
Caution is necessary when salicylates and anticoagulants are prescribed concurrently. Also, salicylates may depress the concentration of prothrombin in the plasma. Salicylates may potentiate sulfonylurea hypoglycemic agents. Large doses of salicylates may have a hypoglycemic action, and thus, affect the insulin requirements of diabetics. Although salicylates in large doses are uricosuric agents, smaller amounts may depress uric acid clearance, and thus, decrease the uricosuric effects of probenecid, sulfinpyrazone and phenylbutazone.