One embodiment relates to a method of treating pulmonary hypertension based upon co-administering to a subject in need thereof a pharmaceutically effective amount of an oral therapeutic agent for treating pulmonary hypertension and a pharmaceutically effective amount of an inhaled therapeutic agent for treating pulmonary hypertension. The benefit of the co-administration of these agents is to eliminate or reduce one or more side effects associated with mono-therapy of either agent, as well as one or more side effects associated with other administration routes such as subcutaneous or intravenous administration.