The nurse is providing instructions about a client's new medications. How should the nurse explain the purpose of probenecid, a uricosuric drug?

Choice A reason: Increased urinary clearance of the multiple medications is not the cause of the client's syncope. Diuresis is a common side effect of some antihypertensive medications, such as diuretics, but it does not lower the blood pressure to a dangerous level. The nurse should monitor the client's fluid and electrolyte balance and urine output, but it is not the priority action in this situation.

Choice B reason: The synergistic effect of the multiple medications is not the cause of the client's syncope. Synergism is when two or more drugs work together to produce a greater effect than the sum of their individual effects. This can be beneficial or harmful, depending on the drugs and the doses. The nurse should check the client's medication history and avoid prescribing drugs that have a negative synergistic effect, but it is not the most likely explanation for the client's hypotension.

Choice C reason: The antagonistic interaction among the various blood pressure medications is not the cause of the client's syncope. Antagonism is when two or more drugs work against each other to reduce or cancel out their effects. This can decrease the effectiveness of the treatment and increase the risk of complications. The nurse should check the client's medication history and avoid prescribing drugs that have a negative antagonistic effect, but it is not the most likely explanation for the client's hypotension.

Choice D reason: The additive effect of multiple medications is the most likely cause of the client's syncope. Additivity is when two or more drugs have a similar effect and their combined effect is equal to the sum of their individual effects. This can lower the blood pressure too much and cause symptoms such as dizziness, fainting, and shock. The nurse should hold the client's scheduled antihypertensive medications and notify the healthcare provider. The nurse should also monitor the client's vital signs, level of consciousness, and perfusion.

Choice A reason: Notifying the healthcare provider of the carbamazepine level is the most appropriate action for the nurse to take. Carbamazepine is an anticonvulsant drug that requires close monitoring of its serum levels to ensure therapeutic and safe effects. The normal reference range for carbamazepine is 4 to 12 mcg/mL or 16.9 to 50.8 mmol/L. A level of 84 mcg/L (35.6 mmol/L) is significantly higher than the upper limit and indicates toxicity. The nurse should report this finding to the prescriber immediately and hold the dose until further instructions.

Choice B reason: Administering the carbamazepine as prescribed is not the most appropriate action for the nurse to take. Giving the evening dose of carbamazepine when the morning level is already toxic can worsen the client's condition and cause serious adverse effects, such as confusion, drowsiness, ataxia, nystagmus, or coma. The nurse should not administer the medication without consulting the prescriber.

Choice C reason: Assessing the client for side effects of carbamazepine is an important action for the nurse to take, but it is not the most appropriate one. The nurse should assess the client for signs and symptoms of carbamazepine toxicity, such as nausea, vomiting, headache, blurred vision, or seizures. However, this action alone is not sufficient to address the problem. The nurse should also notify the prescriber and withhold the dose.

Choice D reason: Withholding this dose of the carbamazepine is a necessary action for the nurse to take, but it is not the most appropriate one. The nurse should not give the evening dose of carbamazepine when the morning level is already toxic, as this can increase the risk of complications. However, this action alone is not enough to resolve the issue. The nurse should also notify the prescriber and follow the appropriate interventions.