HEMODYNAMIC-EFFECTS OF 5-AMINOLEVULINIC ACID IN HUMANS

Endogenous protoporphyrin IX (PpIX), which results from the oral admin istration of 5-aminolevulinic acid (ALA), is being investigated for it s efficacy as a photosensitizing agent for photodynamic therapy (PDT). Clinical use of ALA has been associated with only mild gastrointestin al side effects. The hemodynamic effects of orally administered ALA in doses used for PDT are unknown. Six patients with a significant histo ry of cardiac disease underwent Swan-Ganz catheterization prior to ALA administration and abdominal operation for PDT. Hemodynamic data coll ection began at least 1 h prior to ALA, and continued for at least 4 h subsequently, during which time no other medications were administere d. When compared to measurements made prior to ALA administration, all patients displayed a significant decrease in systolic and diastolic b lood pressures, pulmonary artery systolic and diastolic pressures as w ell as pulmonary vascular resistance. Five of the six patients also de veloped a decrease in systemic vascular resistance. No significant cha nges in pulmonary capillary wedge pressure, cardiac output or cardiac index was observed, but the mean pulse rate rose significantly. These findings cannot be explained on the basis of other cardiovascular depr essants or to poor central volume status. Although no adverse sequela were appreciated as a result of the observed hemodynamic changes, this potential should be recognized in patients undergoing PDT using ALA. (C) 1998 Elsevier Science S.A. All rights reserved.