Levothyroxine has a narrow therapeutic window; therefore, the patient is at risk for adverse effects due to receiving twice the normal dose of levothyroxine. These symptoms include angina pectoris, myocardial infarction, tachycardia, and heart failure; a focused cardiovascular assessment is performed first to determine any supportive care necessary. Once the assessment is finished, the nurse can inform the patient of the mistake, alert the ordering provider of the medication error, and instruct the LPN/LVN to complete an incident report.