An Unlikely Trio: Profound Anemia, Elevated Lactate, and Riociguat

Riociguat (Adempas) is a stimulator of soluble guanylate cyclase approved to treat adult pulmonary arterial hypertension (PAH), World Health Organization (WHO) group 1 pulmonary hypertension (PH), and inoperable or persistent chronic thromboembolic pulmonary hypertension (CTEPH), WHO group 4 PH. Riociguat has been studied predominantly in WHO functional class II and III patients. In the pivotal Pulmonary Arterial Hypertension Soluble Guanylate Stimulator Trial 1 (PATENT-1) clinical trial, anemia was reported in 8% of patients; however, this anemia was typically very mild. We present a unique case of profound anemia and elevated lactate occurring in a patient taking riociguat for treatment of PAH.