Methods for inhibiting intimal hyperplasia in the vasculature of mammals, including primates, are disclosed. The methods comprise administering to the mammal an effective amount of Brefelding A or a derivative of Brefeldin A. The methods are useful in reducing intimal hyperplasia due to, for example, vascular injuries resulting from angioplasty, endarterectomy, reduction atherectomy or anastomosis of a vascular graft. The non-peptide PDGF antagonists Brefeldin A and its derivatives may optionally be administered coordinately with heparin, whereby the coordinately administered of non-peptide PDGF antagonist and heparin are combinatorially effective in inhibiting intimal hyperplasia.