A drug’s administration route influences the quantity given and the rate at which the drug is absorbed and distributed. These variables affect the drug’s action and the patient’s response.
Routes of administration include:
- buccal, sublingual, translingual: certain drugs are given buccally (in the pouch between the cheek and gum), sublingually (under the tongue), or translingually (on the tongue) to speed their absorption or to prevent their destruction or transformation in the stomach or small intestine
- gastric: this route allows direct instillation of medication into the GI system of patients who can’t ingest the drug orally
- intradermal: substances are injected into the skin (dermis); this route is used mainly for diagnostic purposes when testing for allergies or tuberculosis
- intramuscular: this route allows drugs to be injected directly into various muscle groups at varying tissue depths; it’s used to give aqueous suspensions and solutions in oil, immunizations, and medications that aren’t available in oral form
- intravenous: the I.V. route allows injection of substances (drugs, fluids, blood or blood products, and diagnostic contrast agents) directly into the bloodstream through a vein; administration can range from a single dose to an ongoing infusion delivered with great precision
- oral: this is usually the safest, most convenient, and least expensive route; drugs are administered to patients who are conscious and can swallow
- rectal and vaginal: suppositories, ointments, creams, gels, and tablets may be instilled into the rectum or vagina to treat local irritation or infection; some drugs applied to the mucosa of the rectum or vagina can be absorbed systemically
- respiratory: drugs that are available as gases can be administered into the respiratory system; drugs given by inhalation are rapidly absorbed, and medications given by such devices as the metered-dose inhaler can be self-administered, or drugs can be administered directly into the lungs through an endotracheal tube in emergency situations
- subcutaneous (subQ): with the subQ route, small amounts of a drug are injected beneath the dermis and into the subcutaneous tissue, usually in the patient’s upper arm, thigh, or abdomen
- topical: this route is used to deliver a drug through the skin or a mucous membrane; it’s used for most dermatologic, ophthalmic, otic, and nasal preparations.
Drugs may also be given as specialized infusions injected directly into a specific site in the patient’s body, such as an epidural infusion (into the epidural space), intrathecal infusion (into the cerebrospinal fluid), intrapleural infusion (into the pleural cavity), intraperitoneal infusion (into the peritoneal cavity), intraosseous infusion (into the rich vascular network of a long bone), and intra-articular infusion (into a joint).