Routes of administration and retrieval

Last revised by Jeremy Jones on 3 Apr 2023

Routes of administration and retrieval refers to the multiple different routes by which substances can be transferred into (e.g. medication) , or removed from (e.g. pus), the human body. These routes most commonly employ natural non-intimate orifices of the body and therefore are usually not considered invasive.

On the other hand, a more invasive approach may occasionally be necessary, such as using an intimate natural orifice, e.g. per vaginal, a needle-based approach or even full-blown surgery. 

Contrast medium administration is usually intravenous, although almost every conceivable route has been used, although some are now uncommon/unusual.

  • non-invasive

    • per oral (PO): the commonest route for medication

    • sublingual: under the tongue, bypasses the liver

    • buccal: inner surface of the cheek bypasses liver e.g. glyceryl nitrate for angina

    • topical: application directly to the skin

    • transdermal, e.g. skin patches

    • intranasal, e.g. influenza vaccination

    • ocular (a.k.a. ophthalmic), e.g. eye drops

    • otic, e.g. ear drops

    • inhalation: directly into the lungs, e.g. oxygen, Tc-99m DTPA

  • invasive

    • per vaginal (PV): includes pessaries

    • per rectal (PR): bypasses liver

    • per urethral (PU)

    • ​needle

      • intravenous (IV): commonest route for contrast media, drugs, fluids and blood transfusions

      • intra-arterial (IA)

      • intralymphatic (IL): usually into lymph node, rather than lymphatics 4

      • intramuscular (IM)

      • subcutaneous (SC)

      • subdermal: e.g. contraceptive implants 5

      • intracavitary

        • pleural

        • intraperitoneal

        • pericardial

        • epidural

        • intracardiac

      • stoma

      • intra-articular: e.g. direct arthrogram

      • biliary

      • renal e.g. nephrostomy

      • intraosseous, primarily infants for resuscitation

    • surgical

      • laparoscopic

      • open surgery

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