A nurse is caring for a client who has been taking sumatriptan for several months. Which of the following statements by the client indicates a therapeutic response to the medication?

Phenytoin is a hydantoin anticonvulsantthat stabilizes neuronal membranes by delaying the influx of sodium ions during action potentials. It has a narrow therapeutic indexand significant effects on cardiac conduction, specifically lengthening the refractory period. Due to its potential to depress myocardial automaticity, it is strictly avoided in patients with certain pre-existing conduction system abnormalities.

Rationale:

A.Sinus bradycardia is a major contraindication for phenytoin because the drug can further depress cardiac conduction and automaticity. Phenytoin possesses class IB antiarrhythmic properties, which can lead to severe cardiovascular collapse or heart block in patients with slow heart rates. Administering this drug to a bradycardic patient poses a life-threatening risk of asystole.

B.A history of cholecystitis, or inflammation of the gallbladder, does not contraindicate the use of phenytoin for seizure management. While phenytoin is metabolized by the liver, it does not have a direct impact on gallbladder function or the formation of gallstones. The nurse would prioritize monitoring liver enzymes rather than focusing on a history of cholecystitis.

C.Taking vitamin B12 supplements does not prevent a patient from receiving phenytoin, as there is no dangerous interaction between the two. Interestingly, long-term phenytoin use is actually associated with folate deficiency rather than issues with B12. Supplements are generally safe and may be necessary for patients with concurrent nutritional deficiencies during anticonvulsant therapy.

D.Ibuprofen is a non-steroidal anti-inflammatory drug that does not have a documented clinical contraindication with the administration of phenytoin. While phenytoin has many drug-drug interactions involving the cytochrome P450 system, ibuprofen is not typically one that causes toxicity. The nurse can safely administer both medications as long as standard monitoring is performed.

Safe medication administration relies on the elimination of transcription errorsand adherence to established safety guidelines, such as avoiding trailing zeros. The Joint Commission mandates specific labeling standards to prevent dosing inaccuracies that could lead to toxicity or subtherapeutic treatment. Clarifying ambiguous or non-standard prescriptions is a fundamental responsibility of the nurse in maintaining patient safetyand preventing adverse events.

Rationale:

A.The prescription for Clozapine 12.50 mg must be clarified because it contains a trailing zero, which is a prohibited notation according to safety standards. A trailing zero can be misread as 125 mg if the decimal point is missed, leading to a ten-fold dosing error and potential toxicity. Standard practice requires writing the dose as 12.5 mg to ensure clear communication.

B.Lamotrigine 200 mg PO daily is a standard maintenance dose for the treatment of epilepsy or bipolar disorder and does not require clarification. This dosage falls within the typical therapeutic range and the notation is clear and free of dangerous abbreviations or zeros. The nurse should simply continue to monitor the patient for adverse effects like Stevens-Johnson syndrome.

C.Donepezil 23 mg PO daily is an approved dosage for the treatment of moderate-to-severe Alzheimer's disease and is not inherently incorrect. While higher than the starting dose, this specific strength was developed to provide additional cognitive benefits for patients with advanced disease. The notation is clear and follows standard pharmaceutical guidelines, so no clarification is needed based on the dosage.

D.Fluoxetine oral solution 20 mg/5 mL administered via a gastrostomy tube is an appropriate route and dose for a patient who cannot swallow. Liquid formulations are the preferred method for tube administration to prevent clogging and ensure the full dose of the selective serotonin reuptake inhibitor is delivered. This prescription follows clear clinical logic and standard safety practices for enteral medication.