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Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 1 of 7



10 mg/ml

For subcutaneous, intramuscular or intravenous injection only


SteriMax Inc.

2770 Portland Drive

Oakville, Ontario

L6H 6R4

Date of Preparation:

August 31, 2020

Control No.: 232497

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 2 of 7



10 mg/ml

For subcutaneous, intramuscular or intravenous injection only






Phenylephrine Hydrochloride Injection USP is a vasoconstrictor and pressor drug chemically

related to epinephrine and ephedrine.


When applied topically or infiltrated into the tissues, phenylephrine produces vasoconstriction

that lasts longer than that of epinephrine and ephedrine. Its action on the heart contrast sharply

with that of epinephrine and ephedrine, in that it slows the heart rate and increases the stroke

output, inducing no disturbance in the rhythm of the pulse.

In therapeutic doses, it produces little if any stimulation of either the spinal cord or cerebrum. A

singular advantage of this drug is the fact that repeated injections produce comparable effects.


For the maintenance of blood pressure during spinal and inhalation anesthesia, and also for

overcoming peripheral vascular failure in shock and shock-like states, drug-induced hypotension

or hypersensitivity. Employed to overcome paroxysmal supraventricular tachycardia, to prolong

spinal anesthesia and as a vasoconstrictor in regional anesthesia.

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 3 of 7


May be contraindicated in patients with hypertension or ventricular tachycardia or in patients

who are hypersensitive to the drug.

Should be used with extreme caution in elderly patients or those with hyperthyroidism,

bradycardia, partial heart block, myocardial disease or severe arteriosclerosis.

Vasopressors may cause serious cardiac arrhythmias during halothane anesthesia and therefore

should be used only with great caution or not at all.

Contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including

anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain

susceptible people. The overall prevalence of sulfite sensitivity in the general population is

unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in non-

asthmatic people.

Oxytocics: In obstetrics, if vasopressor drugs are either used to correct hypotension or added to

the local anesthetic solution, the obstetrician should be warned that some oxytocic drugs may

cause severe persistent hypertension and that even a rupture of a cerebral blood vessel may occur

during the postpartum period.

MAO Inhibitors: The pressor effects of sympathomimetic pressor amines is markedly

potentiated in patients receiving a monoamine oxidase (MAO) inhibitor. Therefore, when

initiating pressor therapy in these patients, the initial dosage should be small and used with due


The pressor response of adrenergic agents may also be potentiated by tricyclic antidepressants.

Pregnancy: Animal reproduction studies have not been conducted with phenylephrine. It is also

not known whether phenylephrine can cause fetal harm when administered to a pregnant woman

or can affect reproduction capacity. Phenylephrine should be given to pregnant woman only if

clearly needed.

Lactation: It is not known whether this drug is excreted in human milk. Because many are

excreted in human milk, caution should be exercised when phenylephrine is administered to a

nursing woman.

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 4 of 7


Headache, reflex bradycardia, excitability, restlessness and rarely arrythmias.


Symptoms: Overdosage may induce ventricular extrasystoles and short paroxysms of ventricular

tachycardia, sensations of fullness in the head and tingling of the extremities.

Treatment: An excessive elevation of blood pressure may be immediately relieved by an α-

adrenergic blocking agent.


Phenylephrine is generally injected subcutaneously, intramuscularly, slowly intravenously, or in

dilute solution as a continuous intravenous infusion. In patients with paroxysmal supraventricular

tachycardia and, if indicated, in case of emergency, phenylephrine is administered directly

intravenously. The dose should be adjusted according to the pressor response.

Dosage Calculations

Dose required

Use Phenylephrine Hydrochloride Injection USP 10 mg/mL


10 mg

1 mL

5 mg

0.5 mL

1 mg

0.1 mL

For convenience in intermittent intravenous administration, dilute 1 mL of Phenylephrine

Hydrochloride Injection USP 10 mg/mL with 9 mL of Sterile Water for Injection USP.

Dose required

Use diluted Phenylephrine Hydrochloride Injection

USP 1 mg/mL (0.1 %)

0.1 mg

0.1 mL

0.2 mg

0.2 mL

0.5 mg

0.5 mL

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 5 of 7

Mild or Moderate Hypotension:

Subcutaneous or Intramuscular: Usual dose: from 2 to 5 mg. Range: from 1 to 10 mg. Initial dose

should not exceed 5 mg.

Intravenous: Usual dose: 0.2 mg. Range: from 0.1 to 0.5 mg. Initial dose should not exceed 0.5

Injections should not be repeated more often than every 10 to 15 minutes. A 5 mg intramuscular

dose should raise blood pressure for 1 to 2 hours. A 0.5 mg intravenous dose should elevate the

pressure for about 15 minutes.

Severe Hypotension and Shock:

Blood volume depletion should always be corrected as fully as possible before any vasopressor is

administered. When, as an emergency measure, intra-aortic pressures must be maintained to

prevent cerebral or coronary artery ischemia, phenylephrine can be administered before and

concurrently with blood volume replacement.

Higher initial and maintenance doses of phenylephrine are required in patients with persistent or

untreated sever hypotension or shock. Hypotension produced by powerful peripheral adrenergic

blocking agents, chlorpromazine, or pheochromocytomectomy may also require more intensive


Continuous infusion:

Add 10 mg of the drug (1 ml of 1% solution) to 500 mL of Dextrose Injection USP or Sodium

Chloride Injection USP (providing a 1:50 000 solution). To raise the blood pressure rapidly, start

the infusion at about 100 to 180 mcg/minute (based on 20 drops/mL, this would be 100 to 180

drops/minute). When the blood pressure is stabilized (at a low normal level for the individual), a

maintenance rate of 40 to 60 mcg/minute usually suffices (based on 20 drops/mL, this would be

40 to 60 drops/minute). If the drop size of the infusion system varies from 20 drops/mL, the dose

must be adjusted accordingly. If a prompt initial pressor response is not obtained, additional

increments of phenylephrine (10 mg or more) are added to the infusion bottle. The rate of flow is

then adjusted until the desired blood pressure level is obtained. (In some cases, a more potent

vasopressor, such as norepinephrine, may be required). Hypertension should be avoided. The

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 6 of 7

blood pressure should be checked frequently. Headache and/or bradycardia may indicate

hypertension, Arrythmias are rare.

Spinal Anesthesia – Hypotension:

Routine parenteral use of phenylephrine has been recommended by many investigators for the

prophylaxis and treatment of hypotension during spinal anesthesia. It is best administered

subcutaneously or intramuscularly 3 or 4 minutes before injection of the spinal anesthetic. The

total requirement for high anesthetic levels is usually 3 mg for lower levels, 2 mg. For

hypotensive emergencies during spinal anesthesia, phenylephrine may be injected intravenously

beginning with a dose of 0.2 mg. Any subsequent dose should not exceed the previous dose by

more than 0.1 to 0.2 mg and should not be more than 0.5 mg. To combat hypotension during

spinal anesthesia in children a dose of 0.5 to 1 mg/11.3 kg of body weight, administered

subcutaneously or intramuscularly, is recommended.

Prolongation of Spinal Anesthesia:

The addition of 2 to 5 mg of phenylephrine to the anesthetic solution increases the duration of

motor block as much as approximately 50% without any increase in the incidence of

complications such as nausea, vomiting or blood pressure disturbances.

Vasoconstrictor for Regional Analgesia:

Concentrations about 10 times those of epinephrine are recommended. The optimum strength is

1:20 000 (made by adding 1 mg of phenylephrine to every 20 mL of local anesthetic solution).

Some pressor responses can be expected when 2 mg or more are injected.

Paroxysmal Supraventricular Tachycardia:

Rapid intravenous injection (within 20 to 30 seconds) is recommended; the initial dose should

not exceed 0.5 mg and subsequent doses, which are determined by the initial blood pressure

response, should not exceed the preceding dose by more than 0.1 to 0.2 mg and should never

exceed 1 mg.

Drug-Induced Reactions:

Hypotension and occasionally severe shock may result from overdosage or idiosyncrasy

following the administration of certain drugs, especially adrenergic and ganglionic blocking

agents, rauwolfia and veratrum alkaloids and phenothiazine tranquilizers. Patients who receive a

Product Monograph – Phenylephrine Hydrochloride Injection USP

Page 7 of 7

phenothiazine derivative as a preoperative medication are especially susceptible to these

reactions. As an adjunct in the management of such episodes, phenylephrine is a suitable agent

for restoring blood pressure.


Each mL of sterile solution contains: phenylephrine hydrochloride 10 mg in water for injection.

Non-medicinal ingredients: sodium chloride 3.5 mg, sodium citrate 4 mg, citric acid 1 mg and

sodium metabisulfite 2 mg. The pH is adjusted between 3.5 and 5.5 with hydrochloric acid or

sodium hydroxide.

Phenylephrine Hydrochloride Injection USP is available in 1 mL, 5 mL and 10 mL fill volumes.

The air in vials has been displaced by nitrogen gas.


Store between 15 and 30°C. Protect from light.


Discard unused portion


Phenylephrine Hydrochloride Injection USP 1%, Prescribing Information, Omega

Laboratories Ltd., Revision 11/99.

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