A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Neo-Synephrine Indications, Dosage, Storage, Stability - Phenylephrine (Injection)
Neo-Synephrine Indications, Dosage, Storage, Stability - Phenylephrine (Injection)
INDICATIONS
AND USAGE
Phenylephrine hydrochloride is intended for the maintenance of an adequate
level of blood pressure during spinal and inhalation anesthesia and for
the treatment of vascular failure in shock, shock-like states, and drug-induced
hypotension, or hypersensitivity. It is also employed to overcome paroxysmal
supraventricular tachycardia, to prolong spinal anesthesia, and as a vasoconstrictor
in regional analgesia.
DOSAGE AND ADMINISTRATION
Phenylephrine hydrochloride 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 hydrochloride is administered
directly intravenously. The dose should be adjusted according to the pressor
response.
Dosage Calculations
|
Dose Required
|
Use
Phenylephrine HCl Injection 1%
|
|
10 mg
|
1 mL
|
|
5 mg
|
0.5 mL
|
|
1 mg
|
0.1 mL
|
For convenience in intermittent intravenous administration, dilute 1
mL phenylephrine hydrochloride 1% with 9 mL Sterile Water for Injection,
USP, to yield 0.1% phenylephrine hydrochloride.
|
Dose Required
|
Use Diluted
Phenylephrine HCl Injection 0.1%
|
|
0.1 mg
|
0.1 mL
|
|
0.2 mg
|
0.2 mL
|
|
0.5 mg
|
0.5 mL
|
Mild or Moderate Hypotension
Subcutaneously or Intramuscularly: Usual dose, from 2 mg
to 5 mg. Range, from 1 mg to 10 mg. Initial dose should not exceed 5 mg.
Intravenously: Usual dose, 0.2 mg. Range, from 0.1 mg to
0.5 mg. Initial dose should not exceed 0.5 mg.
Injections should not be repeated more often than every 10 to 15 minutes.
A 5 mg intramuscular dose should raise blood pressure for one to two hours.
A 0.5 mg intravenous dose should elevate the pressure for about 15 minutes.
Severe Hypotension and Shock -Including Drug-Related Hypotension
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 hydrochloride can be administered before
and concurrently with blood volume replacement.
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 phenothiazine
derivative as preoperative medication are especially susceptible to these
reactions. As an adjunct in the management of such episodes, phenylephrine
hydrochloride is a suitable agent for restoring blood pressure.
Higher initial and maintenance doses of phenylephrine hydrochloride are
required in patients with persistent or untreated severe hypotension or
shock. Hypotension produced by powerful peripheral adrenergic blocking
agents, chlorpromazine, or pheochromocytomectomy may also require more
intensive therapy.
Continuous Infusion - Add 10 mg of the drug (1 mL of 1
percent 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 µg to 180 µg per
minute (based on 20 drops per mL this would be 100 to 180 drops per minute).
When the blood pressure is stabilized (at a low normal level for the individual)
a maintenance rate of 40 µg to 60 µg per minute usually suffices
(based on 20 drops per mL this would be 40 to 60 drops per minute). If
the drop size of the infusion system varies from the 20 drops per mL,
the dose must be adjusted accordingly.
If a prompt initial pressor response is not obtained, additional increments
of phenylephrine hydrochloride (10 mg or more) are added to the infusion
bottle. The rate of wflow is then adjusted until the desired blood pressure
level is obtained. (In some cases, a more potent vasopressor, such as
norepinephrine bitartrate, may be required.) Hypertension should be avoided.
The blood pressure should be checked frequently. Headache and/or bradycardia
may indicate hypertension. Arrhythmias are rare.
Spinal Anesthesia - Hypotension
Routine parenteral use of phenylephrine hydrochloride has been recommended
for the prophylaxis and treatment of hypotension during spinal anesthesia.
It is best administered subcutaneously or intramuscularly three or four
minutes before injection of the spinal anesthetic. The total requirement
for high anesthetic levels is usually 3 mg, and for lower levels, 2 mg.
For hypotensive emergencies during spinal anesthesia, phenylephrine hydrochloride
may be injected intravenously, using an initial dose of 0.2 mg. Any subsequent
dose should not exceed the previous dose by more than 0.1 mg to 0.2 mg
and no more than 0.5 mg should be administered in a single dose. To combat
hypotension during spinal anesthesia in children, a dose of 0.5 mg to
1 mg per 25 pounds body weight, administered subcutaneously or intramuscularly,
is recommended.
Prolongation of Spinal Anesthesia
The addition of 2 mg to 5 mg of phenylephrine hydrochloride to the anesthetic
solution increases the duration of motor block by as much as approximately
50 percent without any increase in the incidence of complications such
as nausea, vomiting, or blood pressure disturbances.
Vasoconstrictor for Regional Analgesia
Concentrations about ten times those employed when epinephrine is used
as a vasoconstrictor are recommended. The optimum strength is 1:20,000
(made by adding 1 mg of phenylephrine hydrochloride 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 mg to 0.2 mg, and should never exceed
1 mg.
HOW SUPPLIED
Phenylephrine HCl Injection, USP 1% (10 mg/ mL)
| NDC 0517-0299-25 |
1 mL Single Dose Vial |
packaged in boxes of 25
|
| NDC 0517-0405-25 |
5 mL Vial * |
packaged in boxes of 25
|
* FOR PHARMACY USE ONLY
Store at controlled room temperature 15°-30° C (59°-86°
F).
Protect from light. FOR SINGLE USE ONLY. Discard unused portion.
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