WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Accidental Intravascular Injection
Accidental intravascular injection of ORABLOC may be
associated with convulsions, followed by central nervous system or
cardiorespiratory depression and coma, progressing ultimately to respiratory
arrest. Dental practitioners who employ local anesthetic agents including
ORABLOC should be well versed in diagnosis and management of emergencies that may
arise from their use. Resuscitative equipment, oxygen, and other resuscitative
drugs should be available for immediate use. To avoid intravascular injection,
aspiration should be performed before ORABLOC is injected. The needle must be repositioned
until no return of blood can be elicited by aspiration. Note, however, that the
absence of blood in the syringe does not guarantee that intravascular injection
has been avoided.
Small doses of local anesthetics injected in dental
blocks may produce adverse reactions similar to systemic toxicity seen with
unintentional intravascular injections of larger doses. Confusion, convulsions,
respiratory depression and/or respiratory arrest, and cardiovascular
stimulation or depression have been reported. These reactions may be due to
intraarterial injection of the local anesthetic with retrograde flow to the
cerebral circulation. Patients receiving these blocks should be observed
constantly. Resuscitative equipment and personnel for treating adverse
reactions should be immediately available. Dosage recommendations should not be
exceeded [see DOSAGE AND ADMINISTRATION].
Systemic Toxicity
This includes toxicity arising from accidental
intravascular injection of ORABLOC discussed in Section 5.1, as well as that related
to higher systemic concentrations of local anesthetics or epinephrine [see Vasoconstrictor Toxicity]. Systemic absorption of local anesthetics including
ORABLOC can produce effects on the central nervous and cardiovascular systems.
At blood concentrations achieved with therapeutic doses
of ORABLOC, changes in cardiac conduction, excitability, refractoriness,
contractility, and peripheral vascular resistance are minimal. However, toxic
blood concentrations of ORABLOC can depress cardiac conduction and
excitability, which may lead to atrioventricular block, ventricular arrhythmias,
and cardiac arrest, possibly resulting in fatalities. In addition, myocardial
contractility is depressed and peripheral vasodilatation occurs, leading to
decreased cardiac output and arterial blood pressure. ORABLOC should also be
used with caution in patients with heart block as well as those with impaired
cardiovascular function since they may be less able to compensate for
functional changes associated with the prolongation of A-V conduction produced
by these drugs.
Restlessness, anxiety, tinnitus, dizziness, blurred
vision, tremors, depression, or drowsiness may be early warning signs of
central nervous system toxicity.
Careful and constant monitoring of cardiovascular and
respiratory (adequacy of ventilation) vital signs and the patient's state of
consciousness should be performed after each local anesthetic injection of
ORABLOC. Repeated doses of ORABLOC may cause significant increases in blood
levels because of possible accumulation of the drug or its metabolites. The
lowest dosage that results in effective anesthesia should be used to decrease
the risk of high plasma levels and serious adverse effects. Tolerance to
elevated blood levels varies with the status of the patient. Resuscitative
equipment, oxygen, and other resuscitative drugs should be available for
immediate use. Precautions for epinephrine administration, discussed in Section
5.3 should be observed.
Debilitated patients, elderly patients, acutely ill
patients, and pediatric patients should be given reduced doses commensurate
with their age and physical condition [see DOSAGE AND ADMINISTRATION]. No
studies have been performed in patients with liver dysfunction, and caution
should be used in patients with severe hepatic disease.
Vasoconstrictor Toxicity
ORABLOC contains epinephrine, a vasoconstrictor that can
cause local or systemic toxicity and should be used cautiously. Local toxicity
may include ischemic injury or necrosis, which may be related to vascular
spasm. ORABLOC should be used with caution in patients during or following the
administration of potent general anesthetic agents, since cardiac arrhythmias may
occur under such conditions. Patients with peripheral vascular disease and
those with hypertensive vascular disease may exhibit exaggerated
vasoconstrictor response.
The American Heart Association has made the following
recommendation regarding the use of local anesthetics with vasoconstrictors in
patients with ischemic heart disease: “Vasoconstrictor agents should be used in
local anesthesia solutions during dental practice only when it is clear that
the procedure will be shortened or the analgesia rendered more profound. When a
vasoconstrictor is indicated, extreme care should be taken to avoid
intravascular injection. The minimum possible amount of vasoconstrictor should
be used.” (Kaplan, 1986). It is essential to aspirate before any injection to
avoid administration of the drug into the blood stream.
Methemoglobinemia
Cases of methemoglobinemia have been reported in
association with local anesthetic use. Although all patients are at risk for
methemoglobinemia, patients with glucose-6-phosphate dehydrogenase deficiency,
congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise,
infants under 6 months of age, and concurrent exposure to oxidizing agents or
their metabolites are more susceptible to developing clinical manifestations of
the condition. If local anesthetics must be used in these patients, close
monitoring for symptoms and signs of methemoglobinemia is recommended.
Signs of methemoglobinemia may occur immediately or may
be delayed some hours after exposure, and are characterized by a cyanotic skin discoloration
and/or abnormal coloration of the blood. Methemoglobin levels may continue to
rise; therefore, immediate treatment is required to avert more serious central
nervous system and cardiovascular adverse effects, including seizures, coma,
arrhythmias, and death. Discontinue ORABLOC and any other oxidizing agents. Â Depending
on the severity of the signs and symptoms, patients may respond to supportive
care, i.e., oxygen therapy, Â hydration. A more severe clinical presentation may
require treatment with methylene blue, exchange transfusion, or hyperbaric
oxygen.
Anaphylaxis And Allergic-Type Reactions
ORABLOC 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. Sulfite sensitivity is seen more frequently in asthmatic than in
nonasthmatic people.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Studies to evaluate the carcinogenic potential of
articaine HCI in animals have not been conducted. Five standard mutagenicity
tests, including three in vitro tests (the nonmammalian Ames test, the
mammalian Chinese hamster ovary chromosomal aberration test, and a mammalian
gene mutation test with articaine HCl) and two in vivo mouse micronucleus tests
(one with articaine and epinephrine 1:100,000 and one with articaine HCl alone)
showed no mutagenic effects.
No effects on male or female fertility were observed in
rats for articaine and epinephrine 1:100,000 administered subcutaneously in
doses up to 80 mg/kg/day (approximately 2 times the MRHD based on body surface
area).
Use In Specific Populations
Pregnancy
Teratogenic Effects
Pregnancy Category C
There are no adequate and well-controlled studies in
pregnant women with articaine with epinephrine. Articaine hydrochloride and
epinephrine (1:100,000) has been shown to increase fetal deaths and skeletal
variations in rabbits when given in doses approximately 4 times the maximum
recommended human dose (MRHD). ORABLOC should be used during pregnancy only if
the potential benefit justifies the potential risk to the fetus.
In embryo-fetal toxicity studies in rabbits, 80 mg/kg,
subcutaneously (approximately 4 times the MRHD based on body surface area)
caused fetal death and increased fetal skeletal variations, but these effects
may be attributable to severe maternal toxicity, including seizures, observed
at this dose. In contrast, no embryo-fetal toxicities were observed when articaine
and epinephrine (1:100,000) was administered subcutaneously throughout
organogenesis at doses up to 40 mg/kg in rabbits and 80 mg/kg in rats (approximately
2 times the MRHD based on body surface area).
In pre- and postnatal developmental studies subcutaneous
administration of articaine hydrochloride to pregnant rats throughout gestation
and lactation, at a dose of 80 mg/kg (approximately 2 times the MRHD based on
body surface area) increased the number of stillbirths and adversely affected
passive avoidance, a measure of learning, in pups. This dose also produced
severe maternal toxicity in some animals. A dose of 40 mg/kg (approximately
equal to the MRHD on a mg/m² basis) did not produce these effects. A similar
study using articaine and epinephrine (1:100,000) rather than articaine
hydrochloride alone produced maternal toxicity, but no effects on offspring.
Nursing Mothers
It is not known whether ORABLOC is excreted in human
milk. Because many drugs are excreted in human milk, caution should be
exercised when ORABLOC is administered to a nursing woman. When using ORABLOC,
nursing mothers may choose to pump and discard breast milk for approximately 4
hours (based on plasma half-life) following an injection of ORABLOC (to
minimize infant ingestion) and then resume breastfeeding.
Pediatric Use
Safety and effectiveness of ORABLOC in pediatric patients
below the age of 4 years have not been established. Safety of doses greater
than 7 mg/kg (0.175 mL/kg) in pediatric patients has not been established.
The safety and effectiveness of ORABLOC for local,
infiltrative, or conductive anesthesia in both simple and complex dental procedures
have been established in pediatric patients ages 4 to 16 years old. Safety and
effectiveness was established in clinical trials with 61 pediatric patients
between the ages of 4 and 16 years administered another product containing articaine
hydrochloride 4% and epinephrine 1:100,000 injections. Fifty-one of these
patients received doses from 0.76 mg/kg to 5.65 mg/kg (0.9 mL to 5.1 mL) of
articaine HCl for simple dental procedures and 10 patients received doses between
0.37 mg/kg and 7.48 mg/kg (0.7 mL to 3.9 mL) of articaine HCl for complex
dental procedures. Approximately 13% of these pediatric patients required
additional injections of anesthetic for complete anesthesia. Safety of doses
greater than 7 mg/kg (0.175 mL/kg) of articaine HCl in pediatric patients has
not been established. Dosages in pediatric patients should be reduced,
commensurate with age, body weight, and physical condition [see DOSAGE AND
ADMINISTRATION].
Geriatric Use
In clinical trials, 54 patients between the ages of 65
and 75 years, and 11 patients 75 years and over received another product
containing articaine and epinephrine 1:100,000. Among all patients between 65
and 75 years, doses from 0.43 mg/kg to 4.76 mg/kg (0.9 mL to 11.9 mL) of
articaine HCl were administered safely to 35 patients for simple procedures and
doses from 1.05 mg/kg to 4.27 mg/kg (1.3 mL to 6.8 mL) of articaine HCl were
administered safely to 19 patients for complex procedures. Among the 11 patients
≥ 75 years old, doses from 0.78 mg/kg to 4.76 mg/kg (1.3 mL to 11.9 mL)
of articaine HCl were administered safely to 7 patients for simple procedures
and doses of 1.12 mg/kg to 2.17 mg/kg (1.3 mL to 5.1 mL) of articaine HCl were
safely administered to 4 patients for complex procedures.
Approximately 6% of patients between the ages of 65 and
75 years and none of the 11 patients 75 years of age or older required
additional injections of anesthetic for complete anesthesia compared with 11%
of patients between 17 and 65 years old who required additional injections.
No overall differences in safety or effectiveness were
observed between elderly subjects and younger subjects, and other reported
clinical experience has not identified differences in responses between the
elderly and younger patients, but greater sensitivity of some older individuals
cannot be ruled out.
Renal And Hepatic Impairment
No studies have been performed with articaine
hydrochloride 4% and epinephrine 1:200,000 injection or articaine hydrochloride
4% and epinephrine 1:100,000 injection in patients with renal or hepatic
dysfunction [see WARNINGS AND PRECAUTIONS].