The route of administration (ROA) refers to the way in which a drug is taken into the body, which can affect the pharmacokinetics (the way a drug is absorbed, distributed, metabolised, and eliminated) and have a significant impact on its efficacy and side effect profile. E.g.:
- Oral: taken by mouth via pills, capsules, or liquids
- Sublingual: placed under the tongue where it is absorbed directly into the bloodstream
- Inhalation: inhaled into the lungs, e.g. an inhaler
- Topical: applied directly to the skin, e.g. creams or ointments
- Intranasal: applied directly into the nose, e.g. nasal sprays
- Intramuscular: injected into a muscle
- Intravenous: injected directly into a vein for rapid and full absorption into bloodstream
- Rectal: administered rectally, e.g. suppositories