In this article, we cover vasodilators and antianginal cardiovascular medications. The Nursing Pharmacology video series follows along with our Pharmacology Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.
Pharmacology - Nursing Flashcards
Vasodilators: Nitroprusside
Vasodilators are medications that open blood vessels, and nitroprusside (brand name Nitropress) is a vasodilator used in heart failure or a hypertensive crisis. A hypertensive crisis is a severe increase in blood pressure that can lead to a stroke.
Mode of action
Nitroprusside is a vasodilator that works by relaxing the muscles in your arteries and veins to help them dilate or widen. This brings blood pressure down very quickly and allows blood to flow more easily by reducing both preload and afterload, which are the beginning and end stages of the heart pumping. It can also be used to keep blood pressure low during surgery.
Side effects
Nitroprusside carries a black box warning because the severe drop in blood pressure that it causes can be dangerous.
With nitroprusside, there are a few key side effects that are unique and that you don’t see very often in other medications: cyanide toxicity and thiocyanate (cyanide + thiosulfate) toxicity. These are somewhat rare, but do happen. The cyanide ion shows up when the body metabolizes nitroprusside.
Patients can also experience dizziness as well as GI upset.
Nitroprusside might "pruss" (press) you into the ground when your BP rapidly decreases.
Nursing care
If your patient is taking nitroprusside and experiences extreme hypotension as a result, you will need to take some interventions based on your facility policy. This can include raising the patient's legs, decreasing the dose of nitroprusside, and increasing fluids.
To assess for the potential of cyanide toxicity, monitor serum cyanide levels.
This medication must be protected from UV light, so an opaque brown bag should be placed over the IV bag.
Antianginals - nitrates: nitroglycerin, isosorbide mononitrate, isosorbide dinitrate
The important medications you should be familiar with in the antianginal class include nitroglycerin as well as isosorbide mononitrate (brand name Imdur) and isosorbide dinitrate.
Mode of action
Nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate work to treat angina through vasodilation. They decrease the preload of the heart, and they also decrease myocardial oxygen demand (the amount of oxygen the heart needs).
Side effects
The side effects of antianginal medications nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate can include headaches, reflex tachycardia (increased heart rate in response to decreased blood pressure) and orthostatic hypotension.
If you eat some "icy sorbet" it might give you a headache (brain freeze) just like isosorbide medications
Patient teaching
It is vitally important to educate patients that they can NOT take this medication within 24 hours of having taken erectile dysfunction meds (such as sildenafil or tadalafil), as these are also potent vasodilators. When taken in combination, the patient could experience a dangerous or even fatal level of hypotension.
If a patient prescribed sublingual (under-the-tongue) nitroglycerin is at home, they will need to keep that medication stored in a cool, dark place.
If they have chest pain, they can take up to three tablets of their nitroglycerin, but no more.
Instruct your patient that if they are experiencing chest pain, they should first sit/lie down, then place one nitroglycerin tablet under the tongue, then wait five minutes. If they are still having chest pain, they need to call 911 and put a second tablet under the tongue, waiting another five minutes, then if there's still no relief, they can take a third, but no more than three total.
Administration
If you are giving nitroglycerin topically (transdermally/on the skin), make sure you wear gloves or you could absorb some of the medication! You are likely already wearing gloves, but this is something to be aware of since gloves do break.
Transdermal nitroglycerin is often applied on the patient’s chest. When you apply a new dose, make sure to remove the prior dose. Rotate sites, and choose a clean, hairless area to place the new dose. Applying nitroglycerin to the hair doesn’t work!