Forced alkaline diuresis is indicated in which of the following: September 2011
**Core Concept**
Forced alkaline diuresis is a medical treatment used to enhance the excretion of certain toxic substances from the body by manipulating urine pH and flow. This technique exploits the principle of ion trapping, where weakly acidic or weakly basic substances can be trapped in the urine due to their low solubility in alkaline or acidic environments, respectively.
**Why the Correct Answer is Right**
Forced alkaline diuresis involves administering sodium bicarbonate to increase urine pH, thereby ion-trapping weakly acidic substances such as salicylates (e.g., aspirin) and phenobarbital. This technique increases their excretion by reducing their reabsorption in the renal tubules. The kidneys maintain an acidic environment, which favors the reabsorption of weak acids. By increasing urine pH, the weakly acidic substances become more ionized and less reabsorbed, leading to increased urinary excretion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because forced alkaline diuresis is not typically used for acidic substances like para-amino hippuric acid.
**Option B:** This option is incorrect because forced alkaline diuresis is not indicated for basic substances like morphine.
**Option C:** This option is incorrect because forced alkaline diuresis is not a primary treatment for acute kidney injury.
**Clinical Pearl / High-Yield Fact**
Forced alkaline diuresis is a useful technique for enhancing the excretion of certain toxic substances, but it should be used judiciously and under close medical supervision to avoid complications.
**Correct Answer:** C. Barbiturates