Power analysis to determine sample size for a single-cell sequencing study

Question

[halo22]

I am looking into designing a study where the interest is to capture the effect of a drug on gene expression profiles (specific to cellular clusters) in patient's samples before and after the drug administration. Is there a power analysis equivalent for single-cell sequencing to determine the minimum number of patient samples required to see any effect?

[rpolicastro]

What do you mean by cellular heterogeneity exactly?

[halo22]

I have updated the question. I meant to capture gene expression changes.