How often can furosemide be injected into a rat? - briefly
Furosemide is generally given to rats no more than once every 24 hours; dosing more frequently increases the risk of renal toxicity and electrolyte disturbances.
How often can furosemide be injected into a rat? - in detail
Furosemide can be administered to rats by intraperitoneal (IP) or subcutaneous (SC) injection. The maximum safe interval between doses depends on the intended experimental purpose, the selected dose, and the animal’s physiological status.
Typical acute‑study protocols use a single dose of 10–20 mg kg⁻¹, followed by observation for 24 h. For repeated‑dose regimens, most published studies limit administration to once every 24 h. This schedule maintains diuretic efficacy while avoiding cumulative nephrotoxicity and electrolyte disturbances. In chronic‑treatment models, investigators have extended the interval to 48 h only after confirming stable plasma concentrations and absence of weight loss or serum potassium decline.
Key considerations for establishing a dosing schedule:
- Dose magnitude – doses above 30 mg kg⁻¹ increase the risk of severe hypokalemia and renal tubular injury; such regimens usually require a 48‑h interval or longer.
- Route of administration – IP injection yields rapid absorption; SC injection provides slower, more prolonged exposure, allowing slightly longer intervals without loss of effect.
- Animal weight and age – younger or lighter rats exhibit faster clearance; they may tolerate a 12‑h interval at lower doses, whereas adult rats (>250 g) are generally managed with 24‑h spacing.
- Monitoring parameters – daily measurement of body weight, urine output, serum electrolytes, and creatinine informs adjustments; any sign of dehydration or electrolyte imbalance mandates extending the interval or reducing the dose.
- Study duration – for experiments exceeding two weeks, a gradual increase in the dosing interval (e.g., 24 h → 36 h → 48 h) reduces the likelihood of cumulative toxicity.
In summary, the most widely accepted practice for repeated administration of furosemide in rats is a once‑daily injection at 10–20 mg kg⁻¹, with adjustments made according to dose, route, and physiological monitoring. Extending the interval to 48 h is permissible for higher doses or prolonged studies, provided that renal function and electrolyte balance remain within normal limits.