WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Exacerbation Of Angina, Heart Failure, Or Pulmonary
Arterial Hypertension
Because of its increasing blood pressure effects,
VAZCULEP can precipitate angina in patients with severe arteriosclerosis or
history of angina, exacerbate underlying heart failure, and increase pulmonary
arterial pressure.
Peripheral And Visceral Ischemia
VAZCULEP can cause excessive peripheral and visceral
vasoconstriction and ischemia to vital organs, particularly in patients with
extensive peripheral vascular disease.
Skin And Subcutaneous Necrosis
Extravasation of VAZCULEP can cause necrosis or sloughing
of tissue. The infusion site should be checked for free flow. Care should be
taken to avoid extravasation of VAZCULEP.
Bradycardia
VAZCULEP can cause severe bradycardia and decreased
cardiac output.
Allergic Reactions
VAZCULEP 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 nonasthmatic people.
Renal Toxicity
VAZCULEP can increase the need for renal replacement
therapy in patients with septic shock. Monitor renal function.
Risk Of Augmented Pressor Affect In Patients With Autonomic
Dysfunction
The increasing blood pressure response to adrenergic
drugs, including VAZCULEP, can be increased in patients with autonomic
dysfunction, as may occur with spinal cord injuries.
Pressor Effect With Concomitant Oxytocic Drugs
Oxytocic drugs potentiate the increasing blood pressure
effect of sympathomimetic pressor amines including VAZCULEP [see DRUG
INTERACTIONS], with the potential for hemorrhagic stroke.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Carcinogenesis
Long-term animal studies that evaluated the carcinogenic
potential of orally administered phenylephrine hydrochloride in F344/N rats and
B6C3F1 mice were completed by the National Toxicology Program using the dietary
route of administration. There was no evidence of carcinogenicity in mice
administered approximately 270 mg/kg/day (131 times the maximum recommended
daily dose of < 10 mg/day) or rats administered approximately 50 mg/kg/day
(48 times the maximum recommended daily dose of < 10 mg/day) based on body surface
area comparisons.
Mutagenesis
Phenylephrine hydrochloride tested negative in the in
vitro bacterial reverse mutation assay (S.typhimurium strains TA98,
TA100, TA1535 and TA1537), the in vitro chromosomal aberrations assay, the in
vitro sister chromatid exchange assay, and the in vivo rat micronucleus assay.
Positive results were reported in only one of two replicates of the in vitro mouse
lymphoma assay.
Impairment Of Fertility
Studies to evaluate the effect of phenylephrine on
fertility have not been conducted.
Use In Specific Populations
Pregnancy
Pregnancy Category C.
Risk Summary
There are no adequate or well-controlled studies with
phenylephrine hydrochloride injection in pregnant women, nor have animal
reproduction studies been conducted. Published studies in normotensive pregnant
rabbits report early onset labor, increased fetal lethality, and adverse placental
effects with subcutaneous phenylephrine administration during gestation at
doses approximately 1.9 times the total daily human dose. Published studies in
normotensive pregnant sheep report decreased uterine blood flow and decreased
PaO2 in the fetus with intravenous phenylephrine administration during late
gestation at doses less than and similar to the human dose. It is not known
whether VAZCULEP can cause fetal harm when administered to a pregnant woman.
VAZCULEP should be given to a pregnant woman only if the potential benefit justifies
the potential risk to the fetus.
Clinical Considerations
Labor and Delivery
The most common maternal adverse reactions reported in
published studies of phenylephrine use during neuraxial anesthesia during
Cesarean delivery include nausea and vomiting, bradycardia, reactive
hypertension, and transient arrhythmias. Phenylephrine, when administered
during labor or delivery, does not appear to alter either neonatal Apgar scores
or umbilical artery blood-gas status.
Data
Animal Data
Studies in the published literature evaluating
subcutaneously administered phenylephrine (0.33 mg/kg, TID) in normotensive
pregnant rabbits reported fetal deaths, adverse histopathology findings in the
placenta (necrosis, calcification and thickened vascular walls with narrowed lumen)
and possible teratogenic effects (one incidence of clubbed feet, partial
development of the intestine) when treatment was initiated during the first
trimester or later; and premature labor when treatment was initiated at the
second trimester or later. The doses administered were 1.9- times the total
daily human dose of 10 mg/day based on a body surface area comparison. Published
studies in pregnant normotensive sheep demonstrate that intravenous
phenylephrine (4 mcg/kg/min for 30 minutes, equivalent to 3.6 to 4.1 mcg/kg/min
human equivalent dose based on body surface area) administered during the third
trimester of pregnancy decreased uterine blood flow by 42%. This dose is 1.1 to
1.2 times the human bolus dose of 200 mcg/60 kg person based on body surface
area. Mean fetal blood pressure and heart rate fluctuated above and below controls
by about 7% during the infusion. Fetal PaO2 was significantly decreased by approximately
26% of control during the infusion. Likewise, PaCO2 was increased and pH was decreased.
The clinical significance of these findings is not clear; however, the results
suggest the potential for cardiovascular effects on the fetus when
phenylephrine is used during pregnancy.
Nursing Mothers
It is not known whether phenylephrine is present in human
milk. The developmental and health benefits of breastfeeding should be
considered along with the mother's clinical need for VAZCULEP and any potential
adverse effects on the breastfed child from the drug or from the underlying
maternal condition. Exercise caution when VAZCULEP is administered to a nursing
woman.
Pediatric Use
Safety and effectiveness in pediatric patients have not
been established.
Geriatric Use
Clinical studies of phenylephrine did not include
sufficient numbers of subjects aged 65 and over to determine whether they
respond differently from younger subjects. Other reported clinical experience
has not identified differences in responses between the elderly and younger
patients. In general, dose selection for an elderly patient should be cautious,
usually starting at the low end of the dosing range, reflecting the greater
frequency of decreased hepatic, renal, or cardiac function, and of concomitant
disease or other drug therapy.
Hepatic Impairment
In patients with liver cirrhosis [Child Pugh Class B and
Class C], dose-response data indicate decreased responsiveness to
phenylephrine. Start dosing in the recommended dose range but consider that you
may need to give more phenylephrine in this population.
Renal Impairment
In patients with end stage renal disease (ESRD),
dose-response data indicate increased responsiveness to phenylephrine. Consider
starting at the lower end of the recommended dose range, and adjusting dose
based on the target blood pressure goal.