How do you give medicine to a rat? - briefly
Medication can be delivered by oral gavage with a calibrated feeding needle, by mixing the drug into palatable food or water, or by subcutaneous or intraperitoneal injection using a sterile syringe. Select the route that provides precise dosing while minimizing stress to the animal.
How do you give medicine to a rat? - in detail
Administering medication to a laboratory rat requires precise dosing, appropriate delivery method, and careful handling to minimize stress and ensure reproducibility.
First, calculate the dose based on the animal’s weight. Weigh the rat on a calibrated scale, express the result in grams, and convert to kilograms. Multiply the desired dose (mg · kg⁻¹) by the animal’s mass to obtain the exact amount of drug needed. Prepare the solution using a sterile vehicle; record concentration and volume to confirm that the final volume does not exceed 10 mL · kg⁻¹ for oral routes or 2 mL · kg⁻¹ for injectable routes.
Select the delivery route that matches the drug’s pharmacokinetic profile:
- Oral gavage – use a smooth, flexible gavage needle (size 20–22 G for adult rats). Restrain the rat by gently holding the scruff, tilt the head slightly upward, and insert the needle to the back of the throat. Deliver the calculated volume slowly to avoid aspiration. Observe for regurgitation; if it occurs, repeat the procedure with a fresh dose.
- Food or water admixture – dissolve or suspend the compound in a palatable medium. Verify that the animal consumes the entire dose within a defined period (typically 30 min). Record intake to confirm dosing accuracy.
- Subcutaneous injection – employ a 25–27 G needle. Pinch a loose area of skin on the dorsal flank, insert the needle at a shallow angle, and inject the solution. Watch for swelling or leakage.
- Intraperitoneal injection – use a 25–27 G needle, insert at a 30‑degree angle into the lower right quadrant of the abdomen, avoiding the intestines. Inject the dose steadily, then withdraw the needle and apply gentle pressure to the site.
- Intramuscular injection – target the quadriceps or hind‑limb muscle. Use a 26–28 G needle, insert perpendicular to the muscle surface, and deliver the volume slowly.
Throughout the procedure, maintain aseptic technique: wear gloves, use sterile syringes, and disinfect the injection site with 70 % ethanol. After dosing, place the rat in a clean cage with easy access to food and water. Monitor for adverse reactions—respiratory distress, lethargy, or abnormal behavior—for at least 30 min, then at regular intervals for 24 h.
Record all details in the animal log: weight, dose, route, vehicle, lot numbers, and observations. This documentation supports reproducibility and complies with institutional animal care guidelines.