Schizophrenia Q 62
A client’s medication order reads, “Thioridazine (Mellaril) 200 mg P.O. q.i.d. and 100 mg P.O. p.r.n.” The nurse should:
A. Administer the medication as prescribed.
B. Question the physician about the order.
C. Administer the order for 200 mg P.O. q.i.d. but not for 100 mg P.O. p.r.n.
D. Administer the medication as prescribed but observe the client closely for adverse effects.
Correct Answer: B. Question the physician about the order.
The nurse must question this order immediately. Thioridazine (Mellaril) has an absolute dosage ceiling of 800 mg/day. Any dosage above this level places the client at high risk for toxic pigmentary retinopathy, which can’t be reversed. As written, the order allows for administering more than the maximum 800 mg/day; it should be corrected immediately before the client’s health is jeopardized.
Option A: Thioridazine is an oral medication taken in tablet form. The tablets come in either 10 mg, 15 mg, 25 mg, 50 mg, 100 mg, 150 mg, or 200 mg. For schizophrenia, recommendations are to initiate thioridazine at 50 mg to 100 mg three times per day and gradually increase the dose as indicated, to a maximum of 800 mg per day. Of import is the risk of inducing dose-dependent QTc prolongation, and so it is suggested to start low and dose slow. Thioridazine also comes in liquid form at 30 mg/mL and 100 mg/mL.
Option C: Thioridazine is a low potency typical antipsychotic, like chlorpromazine. Unlike higher potency antipsychotics, thioridazine has a lower incidence of extrapyramidal side effects. However, lower potency antipsychotics are more likely to be associated with antimuscarinic, antihistaminic, and antiadrenergic side effects. Thioridazine is metabolized through the liver with a half-life of 24 hours and is excreted in the urine, bile, and feces.
Option D: Patients require monitoring for medication side effects during treatment, and it is often necessary to screen patients before treatment to obtain baseline results. Since thioridazine can cause significant ECG (electrocardiogram) changes and arrhythmias, it is important to get a baseline ECG and potassium level. Furthermore, an additional ECG is recommended for any change in dose and periodically after that. Another possible side effect of thioridazine is leukopenia, and thus routine complete blood counts are recommended over the course of the initial weeks.