Drug delivery devices with reusable components and disposable components

A drug delivery method, comprising:

• coupling a first dispensing head to a first coupler of a body, wherein the first dispensing head includes a coupler;
• coupling a first drug holder to a second coupler of the body such that the first drug holder is not coupled to the coupler of the first dispensing head, the first drug holder containing a first drug therein;
• after coupling the first dispensing head and the first drug holder to the body, causing the first drug to exit the first drug holder and spray out an opening of a tip of the first dispensing head that is positioned in a nose of a patient and causing the first drug holder and the coupler of the first dispensing head to become coupled to one another;
• removing the first dispensing head and the first drug holder as a unit from the body and subsequently coupling a second dispensing head to the first coupler of the body, the second dispensing head including a coupler and coupling a second drug holder to the second coupler of the body such that the second drug holder is not coupled to the coupler of the second dispensing head, the second drug holder containing a second drug therein;
• and
• after coupling the second dispensing head and the second drug holder to the body, causing the second drug to exit the second drug holder and spray out a second opening of a second tip of the second dispensing head that is positioned in the nose of the patient and causing the second drug holder and the coupler of the second dispensing head to become coupled to one another.