PRECAUTIONS
General: The
safety and effectiveness of local anesthetics depend on proper dosage,
correct technique, adequate precautions, and readiness for emergencies.
Resuscitative equipment, oxygen, and other resuscitative drugs should be
available for immediate use. (See WARNINGS, ADVERSE REACTIONS, and OVERDOSAGE.)
During major regional nerve blocks, the patient should have IV fluids
running via an indwelling catheter to assure a functioning intravenous
pathway. The lowest dosage of local anesthetic that results in effective
anesthesia should be used to avoid high plasma levels and serious
adverse effects. The rapid injection of a large volume of local
anesthetic solution should be avoided and fractional (incremental) doses
should be used when feasible.
Epidural Anesthesia: During
epidural administration of Bupivacaine Hydrochloride, 0.5% and 0.75%
solutions should be administered in incremental doses of 3 mL to 5 mL
with sufficient time between doses to detect toxic manifestations of
unintentional intravascular or intrathecal injection. Injections should
be made slowly, with frequent aspirations before and during the
injection to avoid intravascular injection. Syringe aspirations should
also be performed before and during each supplemental injection in
continuous (intermittent) catheter techniques. An intravascular
injection is still possible even if aspirations for blood are negative.
During the administration of epidural anesthesia, it is recommended
that a test dose be administered initially and the effects monitored
before the full dose is given. When using a “continuous” catheter
technique, test doses should be given prior to both the original and all
reinforcing doses, because plastic tubing in the epidural space can
migrate into a blood vessel or through the dura. When clinical
conditions permit, the test dose should contain epinephrine (10 mcg to
15 mcg has been suggested) to serve as a warning of unintended
intravascular injection. If injected into a blood vessel, this amount of
epinephrine is likely to produce a transient “epinephrine response”
within 45 seconds, consisting of an increase in heart rate and/or
systolic blood pressure, circumoral pallor, palpitations, and
nervousness in the unsedated patient. The sedated patient may exhibit
only a pulse rate increase of 20 or more beats per minute for 15 or more
seconds. Therefore, following the test dose, the heart rate should be
monitored for a heart rate increase. Patients on beta-blockers may not
manifest changes in heart rate, but blood pressure monitoring can detect
a transient rise in systolic blood pressure. The test dose should also
contain 10 mg to 15 mg of Bupivacaine Hydrochloride or an equivalent
amount of another local anesthetic to detect an unintended intrathecal
administration. This will be evidenced within a few minutes by signs of
spinal block (e.g., decreased sensation of the buttocks, paresis of the
legs, or, in the sedated patient, absent knee jerk). The Test Dose
formulation of Bupivacaine Hydrochloride contains 15 mg of bupivacaine
and 15 mcg of epinephrine in a volume of 3 mL. An intravascular or
subarachnoid injection is still possible even if results of the test
dose are negative. The test dose itself may produce a systemic toxic
reaction, high spinal or epinephrine-induced cardiovascular effects.
Injection of repeated doses of local anesthetics may cause
significant increases in plasma levels with each repeated dose due to
slow accumulation of the drug or its metabolites, or to slow metabolic
degradation. Tolerance to elevated blood levels varies with the status
of the patient. Debilitated, elderly patients and acutely ill patients
should be given reduced doses commensurate with their age and physical
status. Local anesthetics should also be used with caution in patients
with hypotension or heartblock.
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.
It should be kept in mind at such times that restlessness, anxiety,
incoherent speech, lightheadedness, numbness and tingling of the mouth
and lips, metallic taste, tinnitus, dizziness, blurred vision, tremors,
twitching, depression, or drowsiness may be early warning signs of
central nervous system toxicity.
Local anesthetic solutions containing a vasoconstrictor should be
used cautiously and in carefully restricted quantities in areas of the
body supplied by end arteries or having otherwise compromised blood
supply such as digits, nose, external ear, or penis. Patients with
hypertensive vascular disease may exhibit exaggerated vasoconstrictor
response. Ischemic injury or necrosis may result.
Because amide-local anesthetics such as Bupivacaine Hydrochloride are
metabolized by the liver, these drugs, especially repeat doses, should
be used cautiously in patients with hepatic disease. Patients with
severe hepatic disease, because of their inability to metabolize local
anesthetics normally, are at a greater risk of developing toxic plasma
concentrations. Local anesthetics should also be used with caution in
patients with impaired cardiovascular function because they may be less
able to compensate for functional changes associated with the
prolongation of AV conduction produced by these drugs.
Serious dose-related cardiac arrhythmias may occur if preparations
containing a vasoconstrictor such as epinephrine are employed in
patients during or following the administration of potent inhalation
anesthetics. In deciding whether to use these products concurrently in
the same patient, the combined action of both agents upon the
myocardium, the concentration and volume of vasoconstrictor used, and
the time since injection, when applicable, should be taken into account.
Many drugs used during the conduct of anesthesia are considered
potential triggering agents for familial malignant hyperthermia. Because
it is not known whether amide-type local anesthetics may trigger this
reaction and because the need for supplemental general anesthesia cannot
be predicted in advance, it is suggested that a standard protocol for
management should be available. Early unexplained signs of tachycardia,
tachypnea, labile blood pressure, and metabolic acidosis may precede
temperature elevation. Successful outcome is dependent on early
diagnosis, prompt discontinuance of the suspect triggering agent(s) and
prompt institution of treatment, including oxygen therapy, indicated
supportive measures and dantrolene. (Consult dantrolene sodium
intravenous package insert before using.)
Use in Head and Neck Area: Small
doses of local anesthetics injected into the head and neck area,
including retrobulbar, dental, and stellate ganglion blocks, may produce
adverse reactions similar to systemic toxicity seen with unintentional
intravascular injections of larger doses. The injection procedures
require the utmost care. Confusion, convulsions, respiratory depression,
and/or respiratory arrest, and cardiovascular stimulation or depression
have been reported. These reactions may be due to intra-arterial
injection of the local anesthetic with retrograde flow to the cerebral
circulation. They may also be due to puncture of the dural sheath of the
optic nerve during retrobulbar block with diffusion of any local
anesthetic along the subdural space to the midbrain. Patients receiving
these blocks should have their circulation and respiration monitored and
be constantly observed. Resuscitative equipment and personnel for
treating adverse reactions should be immediately available. Dosage
recommendations should not be exceeded. (See DOSAGE AND ADMINISTRATION.)
Use in Ophthalmic Surgery: Clinicians
who perform retrobulbar blocks should be aware that there have been
reports of respiratory arrest following local anesthetic injection.
Prior to retrobulbar block, as with all other regional procedures, the
immediate availability of equipment, drugs, and personnel to manage
respiratory arrest or depression, convulsions, and cardiac stimulation
or depression should be assured (see also WARNINGS and Use In Head and Neck Area,
above). As with other anesthetic procedures, patients should be
constantly monitored following ophthalmic blocks for signs of these
adverse reactions, which may occur following relatively low total doses.
A concentration of 0.75% bupivacaine is indicated for retrobulbar
block; however, this concentration is not indicated for any other
peripheral nerve block, including the facial nerve, and not indicated
for local infiltration, including the conjunctiva (see INDICATIONS AND USAGE and PRECAUTIONS, General).
Mixing Bupivacaine Hydrochloride with other local anesthetics is not
recommended because of insufficient data on the clinical use of such
mixtures.
When Bupivacaine Hydrochloride 0.75% is used for retrobulbar block,
complete corneal anesthesia usually precedes onset of clinically
acceptable external ocular muscle akinesia. Therefore, presence of
akinesia rather than anesthesia alone should determine readiness of the
patient for surgery.
Information for Patients:
When appropriate, patients should be informed in advance that they may
experience temporary loss of sensation and motor activity, usually in
the lower half of the body, following proper administration of caudal or
epidural anesthesia. Also, when appropriate, the physician should
discuss other information including adverse reactions in the package
insert of Bupivacaine Hydrochloride.
Clinically Significant Drug Interactions:
The administration of local anesthetic solutions containing epinephrine
or norepinephrine to patients receiving monoamine oxidase inhibitors or
tricyclic antidepressants may produce severe, prolonged hypertension.
Concurrent use of these agents should generally be avoided. In
situations when concurrent therapy is necessary, careful patient
monitoring is essential.
Concurrent administration of vasopressor drugs and of ergot-type
oxytocic drugs may cause severe, persistent hypertension or
cerebrovascular accidents.
Phenothiazines and butyrophenones may reduce or reverse the pressor effect of epinephrine.
Carcinogenesis, Mutagenesis, Impairment of Fertility:
Long-term studies in animals of most local anesthetics including
bupivacaine to evaluate the carcinogenic potential have not been
conducted. Mutagenic potential or the effect on fertility has not been
determined. There is no evidence from human data that Bupivacaine
Hydrochloride may be carcinogenic or mutagenic or that it impairs
fertility.
Pregnancy Category C:
Decreased pup survival in rats and an embryocidal effect in rabbits
have been observed when bupivacaine hydrochloride was administered to
these species in doses comparable to nine and five times respectively
the maximum recommended daily human dose (400 mg). There are no adequate
and well-controlled studies in pregnant women of the effect of
bupivacaine on the developing fetus. Bupivacaine hydrochloride should be
used during pregnancy only if the potential benefit justifies the
potential risk to the fetus. This does not exclude the use of
Bupivacaine Hydrochloride at term for obstetrical anesthesia or
analgesia. (See Labor and Delivery.)
Labor and Delivery: SEE BOXED WARNING REGARDING OBSTETRlCAL USE OF 0.75% BUPIVACAINE HYDROCHLORIDE.
Bupivacaine Hydrochloride is contraindicated for obstetrical paracervical block anesthesia.
Local anesthetics rapidly cross the placenta, and when used for
epidural, caudal, or pudendal block anesthesia, can cause varying
degrees of maternal, fetal, and neonatal toxicity. (See CLINICAL PHARMACOLOGY, Pharmacokinetics.)
The incidence and degree of toxicity depend upon the procedure
performed, the type, and amount of drug used, and the technique of drug
administration. Adverse reactions in the parturient, fetus, and neonate
involve alterations of the central nervous system, peripheral vascular
tone, and cardiac function.
Maternal hypotension has resulted from regional anesthesia. Local
anesthetics produce vasodilation by blocking sympathetic nerves.
Elevating the patient’s legs and positioning her on her left side will
help prevent decreases in blood pressure. The fetal heart rate also
should be monitored continuously and electronic fetal monitoring is
highly advisable.
Epidural, caudal, or pudendal anesthesia may alter the forces of
parturition through changes in uterine contractility or maternal
expulsive efforts. Epidural anesthesia has been reported to prolong the
second stage of labor by removing the parturient’s reflex urge to bear
down or by interfering with motor function. The use of obstetrical
anesthesia may increase the need for forceps assistance.
The use of some local anesthetic drug products during labor and
delivery may be followed by diminished muscle strength and tone for the
first day or two of life. This has not been reported with bupivacaine.
It is extremely important to avoid aortocaval compression by the
gravid uterus during administration of regional block to parturients. To
do this, the patient must be maintained in the left lateral decubitus
position or a blanket roll or sandbag may be placed beneath the right
hip and gravid uterus displaced to the left.
Nursing Mothers:
Bupivacaine has been reported to be excreted in human milk suggesting
that the nursing infant could be theoretically exposed to a dose of the
drug. Because of the potential for serious adverse reactions in nursing
infants from bupivacaine, a decision should be made whether to
discontinue nursing or not administer bupivacaine, taking into account
the importance of the drug to the mother.
Pediatric Use:
Until further experience is gained in pediatric patients younger than 12
years, administration of Bupivacaine Hydrochloride in this age group is
not recommended. Continuous infusions of bupivacaine in children have
been reported to result in high systemic levels of bupivacaine and
seizures; high plasma levels may also be associated with cardiovascular
abnormalities. (See WARNINGS, PRECAUTIONS, and OVERDOSAGE.)
Geriatric Use:
Patients over 65 years, particularly those with hypertension, may be at
increased risk for developing hypotension while undergoing anesthesia
with Bupivacaine Hydrochloride. (See ADVERSE REACTIONS.)
Elderly patients may require lower doses of Bupivacaine Hydrochloride. (See PRECAUTIONS, Epidural Anesthesia and DOSAGE AND ADMINISTRATION.)
In clinical studies, differences in various pharmacokinetic
parameters have been observed between elderly and younger patients. (See
CLINICAL PHARMACOLOGY.)
This product is known to be substantially excreted by the kidney, and
the risk of toxic reactions to this drug may be greater in patients
with impaired renal function. Because elderly patients are more likely
to have decreased renal function, care should be taken in dose
selection, and it may be useful to monitor renal function. (See CLINICAL PHARMACOLOGY.)