What are the common routes of drug administration?

Common routes of drug administration include oral, inhalation, injection, topical, and rectal.

Oral administration is the most common and convenient route of drug administration. It involves swallowing a drug in the form of tablets, capsules, or liquid. The drug is then absorbed into the bloodstream through the stomach or small intestine. However, not all drugs can be taken orally as some may be destroyed by stomach acids or may not be absorbed well into the bloodstream.

Inhalation is another common route, especially for drugs used to treat respiratory conditions like asthma. The drug is delivered directly to the lungs, providing a fast and effective treatment. Inhalation can be through a nebuliser, which turns the drug into a fine mist, or through an inhaler, which delivers a measured dose of the drug.

Injection is a route that bypasses the digestive system entirely. Drugs can be injected intravenously (into a vein), intramuscularly (into a muscle), or subcutaneously (under the skin). This route allows for a rapid onset of action and is useful when a quick response is needed, or when a drug cannot be taken orally.

Topical administration involves applying a drug directly onto the skin or mucous membranes. This is commonly used for localised treatment, such as creams for skin conditions or eye drops for eye infections. The drug is absorbed through the skin or mucous membrane and acts at the site of application.

Lastly, rectal administration involves inserting a drug into the rectum, usually in the form of a suppository or enema. This route is often used when a patient cannot take medication orally, for example, if they are vomiting or unconscious. It is also used for local treatment of conditions affecting the rectum or lower bowel.