ABSTRACT
Pulmonary arterial hypertension (PAH) is a disease of the small pulmonary arteries, characterized by intense remodelling resulting in a progressive increase in pulmonary vascular resistance. PAH is a progressive condition that can occur in an idiopathic form or in association with other disease states or exposures and is believed to result from environmental or disease-inciting factors coupled with genetically determined susceptibilities. The identification of drugs and toxins as risk factors for PAH poses a great challenge to both the physician and the epidemiologist. Even though aminorex was withdrawn from the market in 1968, a case series of PAH has been associated with ingestion of its analogue 4-methyl-aminorex in the United States in the context of illicit use as an alternative to methamphetamine. Since only a minority of patients exposed to fenfluramines develop PAH, the need for other predisposing factors, such as genetic susceptibility, could be postulated, with anorexigens acting as a ‘second hit’ in those predisposed subjects.
