Methamphetamine can be bought as a pill, as a powder to be snorted through the nose or injected, or in a crystal form – ice – which is smoked in a pipe.
It has been reported that the protease inhibitor, ritonavir, increases levels of methamphetamine to possibly dangerous levels. Methamphetamine is metabolised by the body using the same mechanism as ritonavir. Doctors believe that inhaling poppers may make the interaction worse.