US Patent 7637891 Method and device for painless injection of medication

A device for painlessly injecting medications, and a method for providing a substantially painless injection of medication into a patient that does not require the use of an anesthetic, that does not require the medical personnel to spend a substantial amount of time performing the injection procedure, that is relatively simple and inexpensive to perform and operate, and that provides a relatively high degree of safety for both the medical personnel and for the patient. The injection needle can have an outside diameter greater than 0.20 mm and less than about 0.38 mm. The medicament can be injected painlessly through the needle and into the patient at a substantially constant volumetric flow rate of about 0.05 μL/s to about 50 μL/s.