Which adverse effect is least likely to occur in a client who is prescribed clozapine?

Clozapine, an atypical antipsychotic, is associated with several potential adverse effects. Among these, myocarditis, while a serious possibility, is less commonly encountered compared to other side effects that can be related to the drug.

Myocarditis is an inflammation of the heart muscle and can occur but is notably rare in the general population of patients taking clozapine. In comparison, seizures, sedation, and akathisia are more frequently reported adverse effects associated with this medication. For instance, seizures may occur due to clozapine’s dose-dependent nature, especially at higher dosages. Sedation is a common side effect of clozapine, often impacting patients early in treatment or when titrating the dose. Akathisia, characterized by a feeling of inner restlessness and an uncontrollable need to be in constant motion, is less frequently associated with clozapine than with typical antipsychotics, but it can still occur.

In summarizing the potential effects, it's clear that myocarditis is the adverse effect that is least likely to manifest in most clozapine-treated patients, making it the correct answer.