RLO: Prescription Writing: Back to Basics

Route of Administration

Each medication has different routes of administration. Sometimes, the same drug can be delivered via many routes. The route of administration determines the bioavailability of the drug (i.e. the proportion of drug that reaches systemic circulation).

For example, an antibiotic delivered intravenously will have a faster onset of action than an antibiotic taken orally.

It is important to state clearly the route of administration of the drug when prescribing as the wrong route may cause harm to the patient.

For example, methotrexate injection which is preservative free can be given intrathecally. However, most methotrexate vials come with preservatives, and can only be given intravenously or as a bolus. Methotrexate that contains preservatives when given intrethecally is fatal.

Abbreviation is often used to indicate the route of administration for each medication. Click on the flip cards to learn which abbreviation is used for the different routes of administration.