**Core Concept:** Eutectic mixture of local anesthetic (EMLA) cream is a topical anesthetic agent used for pain relief during minor skin procedures. It is a combination of two local anesthetics: eutectic mixture of lidocaine and prilocaine.

**Why the Correct Answer is Right:** EMLA cream works by inhibiting voltage-gated sodium channels in nerve fibers, which is crucial for conducting an electrical signal necessary for pain sensation. The combination of lidocaine and prilocaine in EMLA cream enhances the anesthetic effect, as both drugs have different receptor binding affinities and rates of absorption from the skin, resulting in a more rapid onset and prolonged duration of action compared to single local anesthetics.

**Why Each Wrong Option is Incorrect:**

A. **Incorrect Answer:** EMLA cream is not composed of prilocaine only. This option is incorrect because the cream contains a combination of lidocaine and prilocaine to enhance anesthesia.

B. **Incorrect Answer:** EMLA cream does not primarily act on potassium channels. EMLA cream works by blocking voltage-gated sodium channels, not potassium channels, which are involved in repolarization after depolarization rather than initiation of depolarization.

C. **Incorrect Answer:** EMLA cream does not demonstrate a lower potency than single local anesthetics. By combining lidocaine and prilocaine, EMLA cream achieves a synergistic effect, resulting in a more potent and longer-lasting anesthetic effect.

D. **Incorrect Answer:** EMLA cream does not have a slower onset compared to single local anesthetics. The combination of lidocaine and prilocaine in EMLA cream accelerates the onset of anesthesia due to their different receptor binding affinities and rates of absorption from the skin.

**Core Concepts Explained:**

1. EMLA cream is a topical anesthetic used to numb the skin surface.
2. The cream works by blocking voltage-gated sodium channels, inhibiting pain transmission.
3. The combination of lidocaine and prilocaine in EMLA cream results in synergistic effect, enhancing the anesthetic action and prolonging its duration.

**Clinical Application:** EMLA cream is commonly used for procedures involving minor skin punctures, venipuncture, and dermatological procedures to minimize patient discomfort and improve procedural safety and efficiency.