Prospective transplant recipients are being turned down in the US if they have a record of smoking marijuana, even if approved to do so by doctors:
"Most transplant centers struggle with the how to deal with people who have used marijuana, said Dr. Robert Sade, director of the Institute of Human Values in Health Care at the Medical University of South Carolina.
"Marijuana, unlike alcohol, has no direct effect on the liver. It is however a concern ... in that it's a potential indicator of an addictive personality," Sade said."
Transplant recipients go through a phase of having their immune systems repressed in order to avoid the new organ being rejected. This means that they are more vulnerable to severe infection by aspergillus - invasive aspergillosis. Marijuana and tobacco can contain high quantities of aspergillus spores along with other fungi - particularly if they have been dried or stored poorly, so inhaling smoke and air through it can include inhaling large amounts of aspergillus spores.
"Dr. Jorge Reyes, a liver transplant surgeon at the UW Medical Center, said that while medical marijuana use isn't in itself a sign of substance abuse, it must be evaluated in the context of each patient.
"The concern is that patients who have been using it will not be able to stop," Reyes said."