A patient with type 2 diabetes is prescribed glipizide (Glucotrol) 10 mg orally before meals.
The patient inquires, “What is the mechanism of action of this medication in managing my diabetes?” How should the nurse respond?

Choice A rationale:

Insulin is a protein-based hormone that is sensitive to heat and light. Exposure to high temperatures or direct sunlight can cause insulin to break down and become less effective.

Refrigeration helps to maintain the stability and potency of insulin. It is generally recommended to store unopened insulin vials in the refrigerator at a temperature between 36°F and 46°F (2°C and 8°C).

This temperature range helps to slow down the degradation process and ensure that the insulin remains effective until its expiration date.

Choice B rationale:

Insulin should never be frozen. Freezing can cause the insulin to crystallize and become unusable. Once insulin has been frozen, it cannot be thawed and used again.

Choice C rationale:

Opened vials of insulin do not need to be discarded immediately. They can be stored in the refrigerator for up to 28 days, depending on the type of insulin.

However, it is important to note the date that the vial was opened and to discard it after the recommended storage period.

Choice D rationale:

Insulin pens should be stored according to the manufacturer’s instructions. Some insulin pens can be stored at room temperature for a certain period of time, while others must be refrigerated.

It is important to read the instructions that come with the insulin pen to ensure that it is stored properly.

Choice A rationale:

Norepinephrine is a potent vasoconstrictor, meaning it narrows blood vessels. It primarily acts on arteries, but it can also constrict veins to a lesser extent.

Its primary actions are to increase systemic vascular resistance and blood pressure.

It is often used in conditions such as shock to raise blood pressure and improve perfusion to vital organs.

It is not a vasodilator and would not be appropriate for a patient requiring dilation of both arteries and veins.

Choice B rationale:

Nitroglycerin is a vasodilator that primarily acts on veins. It relaxes the smooth muscle in the walls of veins, which allows them to dilate and hold more blood.

This reduces the amount of blood returning to the heart, which in turn lowers preload and reduces cardiac workload.

Nitroglycerin is often used to treat angina pectoris, a condition characterized by chest pain due to insufficient blood flow to the heart.

While it can also have some vasodilatory effects on arteries, its primary action is on veins.

Choice C rationale:

Nitroprusside sodium (Nitropress) is a potent vasodilator that acts on both arteries and veins. It directly relaxes smooth muscle in the blood vessel walls, leading to dilation.

It is a very powerful vasodilator and can rapidly lower blood pressure.

It is often used in hypertensive emergencies to quickly reduce blood pressure and improve cardiac function.

It is also used in conditions such as congestive heart failure and acute aortic dissection to reduce afterload and improve cardiac output.

Choice D rationale:

Lidocaine is a local anesthetic agent that is primarily used to block nerve conduction. It does not have any direct vasodilatory effects.

It is sometimes used in the treatment of cardiac arrhythmias, but its mechanism of action in this setting is not related to vasodilation.