Vaporizing a drug is different than smoking plant e.g. tobacco. When smoking plant material, it is usually burned and the drugs are delivered in the smoke.
Harm Reduction Messages
Through crack and cannabis are dose dependant it is important to
be aware of the damage caused by holding your breath after inhaling
the smoke. Crack vaporises at 90 degrees and does not remain potent
for long. Holding your breath for a very long time after it
has been inhaled does not increase the effect and may make you feel
dizzy. Holding your breath can cause damage in the air sacks
in the lung (alveoli).