HIV medications and party drugs have something in common: both are processed out of your blood stream by your liver. But your liver can only do so much at one time. Overload it and both prescribed and party drugs can build up to dangerous levels in your blood stream. This can lead to overdose or other dangerous conditions, such as a heart attack, stroke, or coma.
In general, protease inhibitors (Ritonavir, Indinavir, Nelfinavir and Saquinavir) and a few other medications used in HIV treatment (Ketoconazole, Itraconazole, and Delaviridine) slow down the action of certain enzymes found in the liver. These enzymes allow the liver to filter specific drugs from of your blood stream and out of your body. With fewer enzymes available, both prescribed medications and party drugs can build up to toxic levels. This toxic build up can cause mild or severe health problems and can definitely ruin your high.