Comprehensive exams for Mental Health Q 150
Cely with manic episodes is taking lithium. Which electrolyte level should the nurse check before administering this medication?
A. Calcium
B. Sodium
C. Chloride
D. Potassium
Correct Answer: B. Sodium
Lithium is chemically similar to sodium. If sodium levels are reduced, such as from sweating or diuresis, lithium will be reabsorbed by the kidneys, increasing the risk of toxicity. Clients taking lithium shouldn’t restrict their intake of sodium and should drink adequate amounts of fluid each day. It is also important to monitor patients for dehydration and lower the dose when there are signs of infection, excessive sweating, or diarrhea. Toxic levels are when the drug level is more than 2 mEq/L.
Option A: Lithium modifies sodium transport in nerve and muscle cells. It alters the metabolism of neurotransmitters, specifically catecholamines, and serotonin. It may alter intracellular signaling via second messenger systems by inhibition of inositol monophosphate. This inhibition, in turn, affects neurotransmission through the phosphatidylinositol secondary messenger system.
Option C: Before starting treatment with lithium, it is essential to get kidney function tests and thyroid function tests. In patients above 50 years of age, an electrocardiogram is also necessary. Repeat these tests once or twice a year in patients on lithium therapy. Because lithium is associated with weight gain, it is important to weigh a patient before starting treatment. It is also beneficial to determine if the patient has prediabetes, diabetes, or dyslipidemia.
Option D: The other electrolytes are important for normal body functions but sodium is most important to the absorption of lithium. Monitoring of therapeutic levels includes trough plasma levels drawn 8 to 12 hours after the last dose. The therapeutic range is 1.0 to 1.5 mEq/L for acute treatment and 0.6 to 1.2 mEq/L for chronic therapy. Monitoring should be done every 1 to 2 weeks until reaching the desired therapeutic levels. Then, check lithium levels every 2 to 3 months for six months.