 The first has long been identified with the Mayo Clinic, and it recommended treatment with beta agonists such as terbutaline, phosphodiesterase-inhibitor theophylline, and leukotriene-receptor antagonists montelukast sodium.The rationale for use of these drugs was their ability to increase intracellular cyclic AMP (adenosine monophosphate) levels, which might counteract inflammatory signaling pathways that induce endothelial permeability.It was the standard of care until the early 2000s, but was sidelined afterwards because patients frequently experienced renewed episodes of SCLS, and because these drugs were poorly tolerated due to their unpleasant side effects.