How do you give furosemide to a rat? - briefly
Inject furosemide dissolved in sterile saline intraperitoneally at 2–5 mg kg⁻¹ using a 27–30 G needle. Adjust the dose according to the experimental protocol and monitor urine output to confirm the diuretic response.
How do you give furosemide to a rat? - in detail
Administering furosemide to a laboratory rat requires precise preparation, accurate dosing, and careful handling to ensure reproducibility and animal welfare.
Preparation of the solution
- Dissolve pharmaceutical‑grade furosemide in sterile saline or 0.9 % NaCl.
- Adjust pH to 7.2–7.4 with NaOH or HCl if needed; the compound is poorly soluble at neutral pH, so a small amount of dimethyl sulfoxide (≤5 % of total volume) may be added to aid dissolution.
- Filter the solution through a 0.22 µm membrane filter into a sterile vial.
- Store at 4 °C and use within 24 h to prevent degradation.
Dose calculation
- Typical dosing range: 1–10 mg kg⁻¹, depending on experimental design.
- Calculate the required volume using the formula:
[ \text{Volume (mL)} = \frac{\text{Desired dose (mg kg⁻¹)} \times \text{Body weight (g)}}{1000 \times \text{Concentration (mg mL⁻¹)}} ] - Verify the rat’s weight immediately before injection; record the value for dose verification.
Route of administration
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Intraperitoneal (IP) injection
- Position the rat on a padded surface, secure gently with a thumb and forefinger to expose the lower right quadrant of the abdomen.
- Insert a 25‑27 G needle at a 30‑45° angle, directing the bevel upward to avoid puncturing the intestines.
- Deliver the calculated volume slowly (≤0.2 mL per 100 g body weight).
- Observe the animal for 2–3 min to ensure no immediate adverse reaction.
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Subcutaneous (SC) injection
- Lift a fold of loose skin on the dorsal neck region.
- Insert a 27‑30 G needle bevel up, perpendicular to the skin.
- Inject the dose at a rate not exceeding 0.1 mL per 100 g.
- Monitor for swelling or leakage at the injection site.
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Intravenous (IV) injection (tail vein)
- Warm the tail with a heat lamp or warm water for 1 min to dilate vessels.
- Place a 30‑32 G catheter or needle into the lateral tail vein.
- Administer the solution over 30–60 seconds; avoid bolus injection to reduce cardiovascular stress.
- Apply gentle pressure to the puncture site after withdrawal of the needle.
Safety and animal welfare
- Use aseptic technique throughout preparation and injection.
- Wear protective gloves and goggles; handle furosemide as a potential irritant.
- Record injection time, dose, route, and any immediate observations in the animal’s log.
- Return the rat to its home cage after a brief observation period (5–10 min) to confirm normal respiration and mobility.
- Dispose of sharps in approved containers and decontaminate work surfaces with 70 % ethanol.
Following these steps provides a reproducible protocol for delivering furosemide to rats, supporting experimental consistency while maintaining ethical standards.