Vasodilators

Question 1

§ Selective dilation of arterioles

Answer 1

Hydralazine

Question 2

§ Selective dilation of veins

Answer 2

§ Nitroglycerin

Question 3

Dilation of arterioles and veins

Answer 3

§ Prazosin

Question 4

Vasodilators

Adverse effects related to vasodilation

Answer 4

§ Postural hypotension
§ Teach patients about symptoms of hypotension (lightheadedness, dizziness) and advise them to sit or lie down if these occur. Avoid abrupt transitions from a supine or seated position to an upright position.
§ Reflex tachycardia
§ Expansion of blood volume

Question 5

Hydralazine

Answer 5

§ Selective dilation of arterioles § Mechanism unknown
§ Postural hypotension minimal
§ Therapeutic uses
§ Essential hypertension § Hypertensive crisis
§ Heart failure

§Adverse effects
§Reflex tachycardia
§Increased blood volume
§Systemic lupus erythematosus– like syndrome
§ Headache, dizziness, weakness, and fatigue
§Drug interactions
§Other antihypertensive agents §Avoid excessive hypotension
§Combined with beta blocker to protect against reflex tachycardia and with diuretics to prevent sodium and water retention and expansion of blood volume

Question 6

Minoxidil

Answer 6

§Selective dilation of arterioles
§More intense dilation than hydralazine, but causes more severe adverse reactions
§Used for severe hypertension unresponsive to safer drugs
§Adverse effects
§Reflex tachycardia §Sodium and water retention § Hypertrichosis §Pericardial effusion
§ Other

Question 7

Sodium Nitroprusside [Nitropress]

Answer 7

§Fastest-acting antihypertensive agent
§Causes venous and arteriolar dilation
§Administration: IV infusion
§Onset: Immediate (BP returns to pretreatment level in minutes when stopped)
§Used for hypertensive emergencies
§Adverse effects §Excessive hypotension
§Cyanide poisoning §Thiocyanate toxicity