A nurse is caring for a client who received 50,000 units of IV heparin rather than the prescribed 5,000 units. Which of the following actions should the nurse take first?

The first priority after a medication error is client safety — assessing for immediate adverse effects. A 10-fold heparin overdose greatly increases bleeding risk, making assessment for bleeding (hematuria, ecchymosis, bleeding gums, hypotension, tachycardia) the immediate priority. The antidote protamine sulfate may be needed. Notifying the risk manager, completing the incident report, and monitoring aPTT are all important subsequent steps, but client assessment comes first.