How do you give a rat an intramuscular injection? - briefly
Secure the rat in a restrainer, expose the thigh or hind‑limb muscle, cleanse the site with alcohol, insert a 25‑27 G needle at a 90° angle into the muscle, deliver the calculated dose, then withdraw the needle and apply gentle pressure. Observe the animal briefly for any adverse reaction before returning it to its cage.
How do you give a rat an intramuscular injection? - in detail
Administering an intramuscular injection to a laboratory rat requires precise preparation, correct technique, and post‑procedure monitoring.
First, gather sterile supplies: a 1‑ml syringe, 25‑27‑gauge needle (0.5‑0.7 mm length), appropriate drug or solution, alcohol swabs, cotton ball, disposable gloves, and a restraining device such as a soft‑tube or a hand‑held restraint. Verify the dose, concentration, and injection volume; rodents tolerate a maximum of 0.1 ml per 10 g body weight in a single site.
Prepare the injection by drawing the calculated volume into the syringe, expelling any air bubbles, and securing the needle. Label the syringe if multiple agents are used.
The preferred site is the lateral thigh muscle (quadriceps) of the hind limb. Locate the injection point by palpating the femur and moving laterally to the muscle bulk, approximately 0.5 cm distal to the hip joint. Clean the skin with an alcohol swab and allow it to dry.
Restrain the rat securely but gently to prevent stress and movement. Hold the animal with the forelimbs supported and the hind limb extended. Insert the needle at a 45‑to‑90‑degree angle, bevel up, penetrating the muscle to a depth of 3‑5 mm depending on the animal’s size. Aspirate briefly to confirm the needle is not in a blood vessel; lack of blood indicates correct placement.
Deliver the dose steadily, avoiding excessive pressure. Withdraw the needle swiftly and apply gentle pressure with a cotton ball to the site for a few seconds to reduce bleeding. Release the animal back into its cage and observe for at least 15 minutes, watching for signs of distress, swelling, or abnormal behavior.
Dispose of all sharps in a designated container, clean the work area, and document the procedure, including drug name, dose, site, and any observations. This systematic approach ensures accurate delivery, minimizes tissue trauma, and maintains animal welfare.