An apparatus for removal of premixed drugs or reconstitution of lyophilized drugs and for the injection of the reconstituted drug into the patient. The apparatus includes a syringe assembly and an adapter assembly that can be removably connected to a medicament container containing a premixed drug or lyophilized medicament. The syringe assembly of the apparatus includes a liquid chamber between the forward end of the body portion and the piston and a syringe cannula assembly. The syringe cannula assembly, which can be removably interconnected with the body portion, comprises a cannula support and a hypodermic needle sealably connected to the cannula support. The adapter assembly comprises an adapter preferably molded from a moldable plastic that includes a top wall, an adapter cannula connected to and extending from the top wall and a variety of connectors connected to the top wall for removably interconnecting the adapter with the medicament container.