Phenylephrine: Difference between revisions

Revision as of 21:39, 23 September 2019

General

Type: Vasopressors
Dosage Forms:
Common Trade Names: Neosynephrine

Adult Dosing

Hypotension

Start 100-200 mcg/min then taper down
- 40-60 mcg/min works for most

"Push dose"
- Inject 1ml (10mg) into 100ml NS Bag = 100mcg/ml
- Draw this into a syringe, each ml is 100mcg
- Give in 0.5-2ml (50-200mcg) alloquots q2-5min

Low Flow Priapism

Dilute phenylephrine 1mg in 9mL NS for final concentration of 100mcg/mL
- For 500 mcg/ml, take 0.5 ml of 10mg/ml phenylephrine, and dilute in 9.5 cc NS
Inject base of penis with 29-Ga needle (after blood aspiration to confirm position)
- 100-500 mcg every 3-5min (max 1000 mcg) until resolution or 1 hour

Pediatric Dosing

Hypotension/Shock
- IV Bolus: 5-20mcg/kg q10-15min prn, 1st dose should not exceed 500mcg with a max dose of 1000mcg
- IV Infusion: 0.1-0.5mcg/kg/min, titrate to desired BP
Nasal Congestion (OTC)
- 4-<6yrs: 2.5mg q4hr prn for <7 days
- 6-<12yrs: 5mg q4hr prn for <7 days

Special Populations

Pregnancy Rating: C
Lactation: infant risk cannot be ruled out
Renal Dosing
- Adult
- Pediatric
Hepatic Dosing
- Adult
- Pediatric

Contraindications

Allergy to class/drug
Severe hypertension
Ventricular tachycardia
Closed angle glaucoma
Caution if:
- Heart failure or cardiogenic shock (cardiac output may decrease with increased SVR)
- Spinal cord injury or other autonomic dysfunction (may experience exaggerated increase in blood pressure)
- Hyperthyroidism

Adverse Reactions

Baroreceptor-mediated reflex bradycardia, particularly in patients with preexisting cardiac dysfunction or severe CAD
If extravasates use phentolamine

Serious

Bradycardia
pulmonary edema
Metabolic acidosis
Decreased renal perfusion
Extravasation

Common

Hypertension
Anxiety
Headache
Rebound congestion, sneezing
Nausea, gastric irritation

Pharmacology

Half-life: 2-3h
Metabolism: extensively in intestinal wall, moderately in liver
Excretion: Urinary
Mechanism of Action: selective α₁ agonist causes vasoconstriction

Primary Receptor

α₁

Relative Effects

↑SVR
↓HR (reflex bradycardia)

Notes

Use with caution in patients with spinal cord injury-related bradycardia
Useful for treatment of vasodilatory shock when norepinephrine or dopamine have precipitated tachyarrhythmias
In patients with ↓LV function, unopposed α₁ may lead to decreased CO or myocardial ischemia
- However clinical trials do not support these effects when used in clinically appropriate dose range

Indication

Neurogenic Shock
Second line agent for septic shock

References

Authors:

@@ Line 2: / Line 2: @@
 *Type: [[Vasopressors]]
 *Dosage Forms:
-*Common Trade Names:
+*Common Trade Names: Neosynephrine
 ==Adult Dosing==
-===Dosing===
+===Hypotension===
-*Start 100-200mcg/min then taper down
+*Start 100-200 mcg/min then taper down
-**40-60mcg/min works for most
+**40-60 mcg/min works for most
+*"[[Push dose pressors|Push dose]]"
+**Inject 1ml (10mg) into 100ml NS Bag = 100mcg/ml
+**Draw this into a syringe, each ml is 100mcg
+**Give in 0.5-2ml (50-200mcg) alloquots q2-5min
+===Low Flow [[Priapism]]===
+*Dilute phenylephrine 1mg in 9mL NS for final concentration of 100mcg/mL
+**For 500 mcg/ml, take 0.5 ml of 10mg/ml phenylephrine, and dilute in 9.5 cc NS
+*Inject base of penis with 29-Ga needle (after blood aspiration to confirm position)
+**100-500 mcg every 3-5min (max 1000 mcg) until resolution or 1 hour
 ==Pediatric Dosing==
+*Hypotension/Shock
+**IV Bolus: 5-20mcg/kg q10-15min prn, 1st dose should not exceed 500mcg with a max dose of 1000mcg
+**IV Infusion: 0.1-0.5mcg/kg/min, titrate to desired BP
+*Nasal Congestion (OTC)
+**4-<6yrs: 2.5mg q4hr prn for <7 days
+**6-<12yrs: 5mg q4hr prn for <7 days
 ==Special Populations==
@@ Line 23: / Line 40: @@
 ==Contraindications==
 *Allergy to class/drug
+*Severe hypertension
+*Ventricular tachycardia
+*Closed angle glaucoma
+*Caution if:
+**Heart failure or cardiogenic shock (cardiac output may decrease with increased SVR)
+**Spinal cord injury or other autonomic dysfunction (may experience exaggerated increase in blood pressure)
+**Hyperthyroidism
 ==Adverse Reactions==
-*Baroreceptor-mediated reflex bradycardia
+*Baroreceptor-mediated reflex bradycardia, particularly in patients with preexisting cardiac dysfunction or severe CAD
 *If extravasates use phentolamine
 ===Serious===
+*Bradycardia
+*pulmonary edema
+*Metabolic acidosis
+*Decreased renal perfusion
+*Extravasation
 ===Common===
+*Hypertension
+*Anxiety
+*Headache
+*Rebound congestion, sneezing
+*Nausea, gastric irritation
 ==Pharmacology==
-*Half-life:
+*Half-life: 2-3h
-*Metabolism:
+*Metabolism: extensively in intestinal wall, moderately in liver
-*Excretion:
+*Excretion: Urinary
-*Mechanism of Action:
+*Mechanism of Action: selective α<sub>1</sub> agonist causes vasoconstriction
 ===Primary Receptor===
-*α1
+*α<sub>1</sub>
 ===Relative Effects===
 *↑SVR
@@ Line 45: / Line 78: @@
 ==Notes==
 *Use with caution in patients with spinal cord injury-related bradycardia
-*Useful for treatment of vasodilatory shock when norepinephrine or dopamine have precipitated tachyarrhythmias
+*Useful for treatment of vasodilatory shock when norepinephrine or [[dopamine]] have precipitated tachyarrhythmias
-*In patients with ↓LV function, unopposed α1 may lead to decreased CO or myocardial ischemia
+*In patients with ↓LV function, unopposed α<sub>1</sub> may lead to decreased CO or myocardial ischemia
 **However clinical trials do not support these effects when used in clinically appropriate dose range
 ===Indication===
 *Neurogenic Shock
+*Second line agent for septic shock
 ==See Also==
+http://www.atsjournals.org/doi/abs/10.1164/rccm.201006-0972CI?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed#readcube-epdf
 ==References==
+<references/>
-<references/>
+[[Category:Pharmacology]] [[Category:Critical Care]]
-[[Category:Pharmacology]]