b. Intravenously (IV). By injection, into the vein. The injection of a drug directly
into the patient's veins is the most rapid route of administration.
c. Intramuscularly (IM). By injection, into muscle. The drugs are injected
deeply into muscle tissue. If the drug is in aqueous (water) solution, absorption is rapid.
However, if the drug is in an oily liquid or in the form of a suspension, it can prolong the
action of the drug.
d. Subcutaneously (Sub-Q). By injection, under the skin. The drug is injected
into the fatty layer under the skin but not into muscle. Absorption of the drug is rapid.
Insulin is normally administered subcutaneously.
e. Infiltration. By injection, into the area next to the target tissue. The drug
then diffuses and penetrates through the nerve sheath. When it contacts the nerve
fibers, they become insensitive to pain and other sensations.
f. Topically. By application to the surface of skin, mucosa, or teeth. Topical
anesthetic agents penetrate through the surface layers, eventually contacting the nerve
endings and producing a loss of pain and sensations. They may be applied as an
ointment, a solution, or a spray. Topical anesthetics are most often used to anesthetize
the buccal mucosa at the site of an injection.
g. Sublingually. By placement under the tongue. The tablet is dissolved under
the tongue or in the pouch of the cheek. (It is not swallowed.) Drugs administered in
this manner are rapidly absorbed. Nitroglycerine in tablet form for heart patients is
probably the most frequently administered sublingual drug.
h. Inhalation. By breathing a gaseous substance. Anesthetics, like nitrous
oxide, are inhaled and exert their effect after absorption into the circulatory system.
Sprays for nasal congestion generally have only a local effect on the tissue in the nose.
a. Agent. An agent is a substance capable of producing a physical, chemical,
b. Allergy. Allergy is a hypersensitivity to a drug. It can result in one or more of
the following conditions.
(1) Anaphylactic shock. This refers to an acute, life-threatening allergic
reaction characterized by low blood pressure, irregular heartbeat, bronchial spasms,
cardiovascular collapse, and circulatory failure after contact with an allergen.