**Core Concept**
Cisatracurium is a non-depolarizing neuromuscular blocker derived from the isomerization of atracurium. It is used in clinical practice for muscle relaxation during anesthesia and has distinct pharmacological properties compared to its parent compound.

**Why the Correct Answer is Right**
Cisatracurium is known for its relatively low incidence of histamine release, which is a significant side effect of atracurium. This difference in histamine release is due to the unique pharmacokinetic profile of cisatracurium, which undergoes Hofmann elimination, a non-enzymatic degradation process that does not involve histamine release. In contrast, atracurium's metabolism involves ester hydrolysis and Hofmann elimination, which can lead to histamine release.

**Why Each Wrong Option is Incorrect**
**Option A:** Cisatracurium is indeed the pure cis isomer of atracurium, which distinguishes it from the racemic mixture of atracurium. This isomerization leads to differences in its pharmacological properties.
**Option B:** Cisatracurium is actually less potent than atracurium, with an ED95 (effective dose 95) of 0.15-0.3 mg/kg compared to atracurium's ED95 of 0.2-0.4 mg/kg.
**Option D:** The metabolism of cisatracurium involves Hofmann elimination, which is distinct from the metabolism of atracurium. While both compounds undergo Hofmann elimination, the ester hydrolysis pathway of atracurium contributes to its metabolism, whereas cisatracurium's metabolism is primarily through Hofmann elimination.

**Clinical Pearl / High-Yield Fact**
When choosing a non-depolarizing neuromuscular blocker for anesthesia, consider the patient's risk factors for histamine release, such as allergies or cardiovascular disease. Atracurium may not be the best choice in these cases due to its potential for histamine release.

**✓ Correct Answer: C. It is also causes histamine release like atracurium**