Portable gas operating inhaler

An inhaler for introducing a drug into a user, said inhaler comprising:

• a first chamber having a compressed gas at a first pressure contained therein, said first chamber being substantially free of any drug;
• a second chamber in selective flow communication with said first chamber, said second chamber having a second compressed gas in which said second pressure being lower than the first pressure and said second chamber being substantially free of any drug, said first and second chambers cooperating so as to yield said second pressure of said compressed gas within said second chamber upon use of said inhaler;
• a means for delivering two different volumes of gas in successive applications from the second chamber;
• a venturi section coupled to said second chamber, said venturi section containing said drug and adapted for effectively receiving a portion of said compressed gas from said second chamber to aerosolize said drug to thereby produce a drug cloud;
• a mouthpiece coupled to said venturi section, and adapted to receive said drug cloud and convey said drug cloud to said user a first housing disposed within said first chamber;
• a second housing disposed within said second chamber having an opening therein;
• and a piston slidably disposed within said first and second housings.