Nedocromil is an inhaled anti-inflammatory agent for the preventive management of asthma.Nedocromil sodium (10(-4) M) decreased LTB4 releasability and intracellular 5-HETE concentrations in zymosan-stimulated AM from asthmatic patients, and was shown to decrease the LTC4 or LTE4-promoted formation of LTB4 and 5-HETE. Eight atopic asthmatic subjects inhaled nedocromil or placebo before the AMP challenge. Spirometry and FE(NO) were measured at intervals over a 24-h period. Nedocromil gave partial protection against this decrease in FE(NO). The time-FE(NO) curve (AUC(0-24)) differed significantly between nedocromil and placebo: 2.7% (-3.6 to -9) vs. -6.6% (-12 to -1.3) FE(NO) changes h(-1), P < 0.002, respectively. Nedocromil protected against AMP-induced bronchoconstriction (AMP PC(20)) [nedocromil 182 (72.5-291) mg mL(-1) vs. placebo 21.7 (10.7-33) mg mL(-1), P < 0.002]. Nedocromil sodium relieved symptoms of allergic conjunctivitis and further support a role for nedocromil sodium in the prevention of allergic conjunctivitis. Nedocromil, 2 to 20 mg/kg, significantly (P<0.05) inhibited cell adhesion and emigration, as well as myeloperoxidase release, in wild-type but not Anx-A1(-/-) mice.