Vasodilators

Vasodilators are medications that directly affect the smooth muscle of arteries and are used to treat hypertension. The most common direct-acting vasodilators are hydralazine and minoxidil. Alright, let’s focus on hydralazine.

Hydralazine relaxes the smooth muscle of the arteries by inhibiting intracellular calcium release within the smooth muscle cells, which inhibits its ability to contract, leading to vasodilation, decreased peripheral vascular resistance, and decrease in blood pressure.

Okay, so the side effects of hydralazine are mostly related to their vasodilatory effects, which cause hypotension; reflex tachycardia, where the sympathetic nervous system is stimulated to increase the heart rate in response to decreased peripheral vascular resistance and hypotension; flushing; headache; and dizziness. Other more serious side effects of hydralazine are related to sodium and water retention and include peripheral edema, pulmonary edema, and dyspnea. Although the mechanism of action is unclear, hydralazine can also cause lupus-like symptoms, such as malaise, myalgia, and fever.

Now, contraindications for use of hydralazine include certain cardiovascular diseases since a sudden drop in blood pressure and subsequent reflex tachycardia can lead to increased myocardial oxygen demand, angina, and myocardial infarction; and certain cerebrovascular diseases because vasodilation can increase cerebral blood flow, resulting in increased intracranial pressure. Hydralazine should also be avoided in patients with septic shock due to its vasodilatory effects.

When caring for your patient who has been prescribed hydralazine, begin by assessing for contraindications to therapy. Then, perform a baseline physical assessment including your patient’s weight, vital signs, and cardiovascular, respiratory, and neurological status. Next, be sure to review your patient’s most recent laboratory test results, including CBC, electrolytes, and hepatic and renal function; as well as the results of any diagnostic tests like ECG. Following administration, monitor their blood pressure and heart rate closely, assess them for side effects, and evaluate the effectiveness of vasodilator therapy.

Okay, let’s move on to patient teaching. Focus your teaching on safe medication administration and remind them that they should never abruptly stop their medication. Also, teach your patient how to measure their own blood pressure and heart rate. Let them know they can take their medication with or without food, but remind them to be consistent, since food increases the bioavailability of hydralazine. Additionally, encourage your patient to immediately report any lupus-like symptoms like fever, muscle aches or increased fatigue to their health care provider, as well as symptoms of pulmonary edema, like shortness of breath.

Alright, as a quick recap... Vasodilators, like hydralazine, are medications that directly affect the smooth muscle of arteries and are used to treat hypertension. Common side effects of hydralazine include hypotension, reflex tachycardia, and peripheral edema. Nursing considerations for vasodilator therapy include establishing a baseline assessment, monitoring for side effects, evaluating the effectiveness of therapy, and providing patient education