Phenylephrine

It is a powerful vasoconstrictor which is commonly used to dilate the pupils and relieve nasal congestion. Available as injection under the brand name, VAZCULEP (phenylephrine hydrochloride), it is an intravenous medication first approved by the US FDA in 1954.

Chemical structure of Phenylephrine

Chemical structure of Phenylephrine

What are the uses of Phenylephrine?

Phenylephrine hydrochloride) Injection is an alpha-1 adrenergic receptor agonist indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia.

What is the recommended dosage?

• VAZCULEP (phenylephrine hydrochloride) Injection, 10 mg/mL, is injected intravenously either as a bolus or in a dilute solution as a continuous infusion.
• Dosing for treatment of hypotension during anesthesia  Bolus intravenous injection: 40 mcg to 100 mcg every 1-2 minutes as needed, not to exceed 200 mcg.
• Intravenous infusion: 10 mcg/min to 35 mcg/min, titrating to effect, not to exceed 200 mcg/min.
• The dose should be adjusted according to the pressor response (i.e., titrate to effect).

Phenylephrine 3D

Phenylephrine 3D

How is this medication supplied?

1. 1 mL single use vials containing 10 mg phenylephrine hydrochloride (10 mg/mL)
2. 5 mL pharmacy bulk package vials containing 50 mg phenylephrine hydrochloride (10 mg/mL)
3. 10 mL pharmacy bulk package vials containing 100 mg phenylephrine hydrochloride (10 mg/mL)

What are the warnings and precautions I should be aware of?

• Extravasation during intravenous administration may cause necrosis or sloughing of tissue
• Severe bradycardia and decreased cardiac output
• Allergic-type reactions: Sulfite
• Concomitant use with oxytocic drugs: Pressor effect of sympathomimetic pressor amines is potentiated

What side effects can this medication cause?

Most common adverse reactions during treatment include nausea, vomiting, and headache.

What drug interactions can this medication cause?

• Agonistic effects with monoamine oxidase inhibitors (MAOI), oxytocin and oxytocic drugs, tricyclic antidepressants, angiotensin and aldosterone, atropine, steroids, norepinephrine transporter inhibitors, ergot alkaloids
• Antagonistic effects with α-adrenergic antagonists, phosphodiesterase Type

Can this medication be used in pregnancy?

No. Based on animal data, may cause fetal harm.

• Dailymed label info on Phenylephrine
• FDA Phenylephrine