**Core Concept**
Amphotericin B is a polyene antifungal medication with a narrow therapeutic index, making it prone to nephrotoxicity and other adverse effects. Its toxicity is related to its ability to bind to cell membranes, causing disruption of membrane function and cell lysis.

**Why the Correct Answer is Right**
Lipid formulations of amphotericin B, such as liposomal amphotericin B, have been developed to reduce its toxicity. These formulations use lipids to encapsulate the drug, reducing its interaction with cell membranes and subsequent nephrotoxicity. The lipid formulation decreases the amount of free amphotericin B available to bind to cell membranes, thereby reducing its toxic effects.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a method to reduce amphotericin B toxicity. While some antifungal medications have been combined with amphotericin B to enhance their efficacy, this does not necessarily reduce the toxicity of amphotericin B itself.
**Option B:** This option is incorrect because increasing the dose of amphotericin B does not reduce its toxicity. In fact, increasing the dose can lead to increased nephrotoxicity and other adverse effects.
**Option C:** This option is not relevant to reducing amphotericin B toxicity. While hydration is important in the administration of amphotericin B to reduce nephrotoxicity, it is not a method to reduce toxicity in the same way as lipid formulations.

**Clinical Pearl / High-Yield Fact**
Lipid formulations of amphotericin B have been shown to reduce nephrotoxicity and other adverse effects, making them a preferred choice for patients at high risk of toxicity.

**Correct Answer:** C. Lipid formulations of amphotericin B.