Pulmonary Arterial Hypertension Secondary to Anorexigens and Other Drugs and Toxins

Abstract

Several drugs and toxins have been shown to be associated with the development of pulmonary vascular hypertension. Pulmonary hypertension (PH) related to these factors has been classified as primary PH (PPH), currently referred to as idiopathic pulmonary arterial hypertension, because its morphological findings, clinical manifestations, hemodynamic measures, and pathological changes were reported to be similar to those of PPH. In 1998, a clinical classification of PH was proposed, the "Evian classification," which was updated in 2003. According to the revised clinical classification of PH, this disease with identifiable risk factors is called "pulmonary arterial hypertension (PAH) associated with drugs and toxins". However, some drugs can be associated with pulmonary veno-occlusive disease (PVOD), persistent PH of the newborn (PPHN), and newly recognized systemic disease, in which the histopathological findings are characterized by pulmonary arteriopathy with medial hypertrophy of muscular and elastic arteries, dilation and intimal atheromas of elastic pulmonary arteries, and right ventricular hypertrophy. Plexogenic arteriopathy can be seen with the exception of PAH of persistent fetal circulation. The identification of drugs and toxins as risk factors for PH poses a great challenge to both the physician and the epidemiologist. Drugs and toxins are categorized according to the strength of their association with PH and the probability of causal role. Table 1 summarizes the drugs and toxins considered in this chapter.