Prior to administering chlorpromazine (Thorazine) to an agitated client, the nurse should:
A. Assess skin color and sclera
B. Assess the radial pulse
C. Take the client’s blood pressure
D. Ask the client to void
Correct Answer: C. Take the client’s blood pressure
Because chlorpromazine (Thorazine) can cause a significant hypotensive effect (and possible client injury), the nurse must assess the client’s blood pressure (lying, sitting, and standing) before administering this drug. When administered as intramuscular or intravenous injections, it may cause hypotension and headache. Prolonged use of chlorpromazine may cause corneal deposits and lens opacity. It may prolong the QT interval.
Option A: If the client had taken the drug previously, the nurse would also need to assess the skin color and sclera for signs of jaundice, a possible drug side effect; however, based on the information given here, there is no evidence that the client has received chlorpromazine before.
Option B: The hepatic P450 enzyme CYP2D6 metabolizes the drug, and its half-life is approximately 30 hours. It gets excreted from the body via urine and in bile. Studies have shown the correlation between chlorpromazine’s therapeutic level and the improvement of the psychiatric symptoms. Researchers have noted that the patients receiving chronic treatment with chlorpromazine have lower plasma levels as compared to the patients acutely treated on an oral dose of chlorpromazine.
Option D: Although the drug can cause urine retention, asking the client to avoid will not alter this anticholinergic effect. Chlorpromazine is a low-potency antipsychotic that mainly causes non-neurologic side effects. It is highly lipid-soluble and stored in body fats, thus very slow to be removed from the body. Being a low-potency typical antipsychotic, it primarily causes dry mouth, dizziness, urine retention, blurred vision, and constipation by blocking the muscarinic receptors. There is a risk of angle-closure glaucoma in the elderly. It also causes sedation due to the blockade of histamine H1 receptors.