Which medication is an oral hypoglycemic agent that stimulates insulin release?

Choice A rationale

Beta-blockers reduce the workload on the heart by blocking the effects of catecholamines (epinephrine and norepinephrine) on beta-adrenergic receptors. This action leads to a decrease in heart rate, a reduction in the force of myocardial contraction (contractility), and a decrease in blood pressure. These effects collectively lower the heart's oxygen demand, which is crucial in preventing further damage after a myocardial infarction.

Choice B rationale

Beta-blockers do the opposite of this. They reduce heart rate and contractility by inhibiting the sympathetic nervous system's effect on the heart. This action is beneficial because it reduces the heart's workload and oxygen demand, helping to prevent further ischemic damage. Increasing heart rate and contractility would be detrimental to a post-MI patient as it would increase myocardial oxygen demand.

Choice C rationale

While beta-blockers do not directly cause coronary artery vasodilation, they improve overall coronary blood flow by reducing heart rate and increasing diastolic time. This allows more time for blood to flow through the coronary arteries to the myocardium. Calcium channel blockers or nitrates are the medications primarily used for direct vasodilation of the coronary arteries.

Choice D rationale

Beta-blockers do not prevent the formation of blood clots. This is the primary function of antiplatelet agents (like aspirin or clopidogrel) and anticoagulants (like heparin or warfarin). These medications work by inhibiting different parts of the coagulation cascade or platelet aggregation to prevent thrombosis in the coronary arteries.

Choice A rationale

Ethambutol is an antituberculosis medication. The combination of a sore throat and fever can be indicative of a serious and potentially life-threatening adverse effect of the medication, such as hepatotoxicity or bone marrow suppression, which could manifest as agranulocytosis. Continuing the medication would be highly dangerous and could worsen the patient's condition.

Choice B rationale

Sore throat and fever can signal a severe systemic reaction to ethambutol, potentially indicating drug-induced agranulocytosis or hepatotoxicity. Agranulocytosis, characterized by a critically low white blood cell count (normal range for WBC is 4,500 to 11,000 cells/mm), leaves the body vulnerable to overwhelming infection. Immediate discontinuation of the drug and notifying the healthcare provider is the essential nursing action.

Choice C rationale

Increasing the dose of a medication when a patient is exhibiting signs of a potential adverse drug reaction is contraindicated. The symptoms of sore throat and fever suggest a systemic inflammatory or immune response to the drug. Increasing the dose would likely exacerbate the toxicity and further harm the patient, potentially leading to a more severe outcome.

Choice D rationale

A sore throat and fever in a patient on ethambutol could be a sign of a severe adverse drug reaction, not just a simple bacterial infection. While an infection may be present, the primary concern is the potential for bone marrow suppression. Prescribing an antibiotic without a proper diagnosis would be an inappropriate nursing action, as it is outside the scope of practice and would fail to address the underlying issue.