Injections

Injections are a method of delivering liquid substances into the body using a syringe and needle, or by needle-free devices. They can target different body compartments depending on the goal, including intramuscular (into a muscle), subcutaneous (under the skin), intravenous (into a vein), intradermal (within the skin), intrathecal (into the spinal canal), intra-articular (into a joint), and epidural (around the spinal cord). The route influences absorption, onset of action, and duration.

Equipment and technique commonly involve sterile syringes and needles of various gauges, vials or ampoules for drugs, and sterile preparation surfaces. Drugs may be administered directly or after reconstitution or dilution. Safe practice emphasizes aseptic technique, hand hygiene, proper disposal, and avoidance of needle reuse. Used needles or syringes must be placed in sharps containers to reduce injury risk.

Injections serve therapeutic, diagnostic, and preventive purposes. They are used for vaccines, analgesia, hydration, hormone therapies, antibiotic or chemotherapy administration, and local therapies such as corticosteroid injections into joints or soft tissues. Diagnostic tests include intradermal tuberculin testing and allergy skin testing. Some procedures employ regional anesthesia or delivery of contrast agents for imaging.

Safety considerations include risks such as pain, bleeding, infection at the injection site, nerve injury, tissue damage, and allergic or systemic reactions. Contraindications may include known allergy to the substance or medical conditions that favor alternative routes. Healthcare providers follow guidelines to minimize risk, monitor patients, and educate on aftercare. Proper disposal of sharps is essential to prevent injuries.