a. Subcutaneous (Hypodermic) Injection. The drug is injected by syringe and
needle into the tissues just beneath the skin. A preparation for subcutaneous use must
be a sterile liquid capable of complete absorption or it will irritate the tissues. Although
the subcutaneous injection may be given in almost any area of the body, the usual sites
are the lateral (outer) aspect of the upper arms and the anterior (front) surface of the
b. Intramuscular Injection. The drug is injected into a muscle, usually in the
buttocks, sometimes in the upper arm or the thigh. The needle is inserted at a 90
degree angle to the skin, through the skin and subcutaneous tissue into the underlying
c. Intradermal Injection. The drug is injected into the upper layers of the skin,
rather than under the skin as in a subcutaneous injection. Minute amounts (0.1 ml) and
less are given intradermally, usually to test for drug sensitivity before administering
larger amounts by other methods. The medial (inner) surface of the forearm is the site
most frequently used.
CONTROL OF NEEDLES AND SYRINGES
Needles and syringes are controlled IAW local SOP.
1-10. PATIENT SAFETY
Patient safety is a critical factor. You must learn how to administer medications
correctly. Wrong injections of some medications may seriously harm or kill a patient.
Aseptic technique must be strictly maintained during the preparation and administration
of a drug. Failure to do so could result in the introduction of foreign particles or other
types of contamination directly into the body. Infection may be introduced through the
needle puncture in the skin, and irreparable damage to a major nerve or other structure
may occur due to improper technique or a dull needle.
1-11. INSTRUMENTS USED TO ADMINISTER A PARENTERAL INJECTION
Administering medicine by injection requires needles and syringes that are
sterile, accurate in measuring dosages, and convenient to use. Using the correct
equipment for injection will minimize discomfort or danger to the patient. Figure 1-1
illustrates a disposable rigid plastic container and a disposable needle and syringe.
a. The needle is a tube with a cutting edge that punctures beneath the protective
area of the skin. It is made of steel or other metal and is generally disposable. The
parts of a needle consist of a lumen (cavity through which medication flows), bevel
(slanted tip/cutting edge), hub, and cannula (shaft) (see figure 1-2). The needle comes
in standard lengths from one-half inch to six inches (see figure 1-3). The length is
determined by measuring from the tip of the point to the junction of the shaft. The
choice of length depends on the route ordered for administration. The choice of needle
gauge depends upon the thickness (viscosity) of the medication. The gauge is