48
Vasodilators (cont'd)
Direct Hydralazine • Initial 10 mg via
slow IV infusion
(maximum initial
dose 20 mg ).
• Repeat every 4–6 h
as needed.
• BP begins to decrease
within 10–30 min,
and the fall lasts
2–4 h.
• Unpredictability
of response and
prolonged duration
of action do not make
hydralazine a desirable
first-line agent for
acute treatment in
most patients.
Adrenergic blockers
Beta1 receptor
selective
antagonist
Esmolol • Loading dose
500–1000 mcg/
kg/min over 1 min
followed by a
50 mcg/kg/min
infusion.
• For additional
dosing, the bolus
dose is repeated
and the infusion
increased in
50 mcg/kg/min
increments as
needed to a
maximum of
200 mcg/kg/min.
• Contraindicated
in patients with
concurrent beta-
blocker therapy,
bradycardia, or
decompensated HF.
• Monitor for
bradycardia.
• May worsen HF.
• Higher doses may
block beta2 receptors
and impact lung
function in reactive
airway disease.
Combined
alpha1 and
nonselective
beta receptor
antagonist
Labetalol • Initial 0.3–1.0-mg/
kg dose (maximum
20 mg ) slow IV
injection every 10
min or 0.4–1.0-mg/
kg/h IV infusion up
to 3 mg/kg/h.
• Adjust rate up to
total cumulative
dose of 300 mg.
• This dose can be
repeated every
4–6 h.
• Contraindicated
in reactive airways
disease or chronic
obstructive pulmonary
disease.
• Especially useful
in hyperadrenergic
syndromes.
• May worsen HF and
should not be given in
patients with second-
or third-degree heart
block or bradycardia.
Table 15. Intravenous Antihypertensive Drugs for Treatment
of Hypertensive Emergencies (cont'd)
Class Drug(s) Usual Dose Range Comments
Resistant Hypertension
