The nurse is reviewing medication errors. Which situation is an example of a medication error?

Choice A reason: Allergic reactions are adverse drug effects, not necessarily medication errors. Documentation of allergies before administration prevents such events. Choice B reason: Administering a double dose results directly from improper preparation, constituting a clear medication error requiring immediate reporting and corrective action. Choice C reason: Patient refusal is not a medication error but a decision. Nurses must document refusals and provide education on medication importance. Choice D reason: Persistent pain indicates ineffective medication, which is an issue of treatment efficacy, not an error in administration.