WARNINGS
Contains acetone sodium bisulfite, 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.
LOCAL ANESTHETICS SHOULD ONLY BE EMPLOYED BY CLINICIANS WHO ARE WELL VERSED IN DIAGNOSIS AND MANAGEMENT OF DOSE-RELATED TOXICITY AND OTHER ACUTE EMERGENCIES WHICH MIGHT ARISE FROM THE BLOCK TO BE EMPLOYED, AND THEN ONLY AFTER INSURING THE IMMEDIATE AVAILABILITY OF OXYGEN, OTHER RESUSCITATIVE DRUGS, CARDIOPULMONARY RESUSCITATIVE EQUIPMENT, AND THE PERSONNEL RESOURCES NEEDED FOR PROPER MANAGEMENT OF TOXIC REACTIONS AND RELATED EMERGENCIES. (See also ADVERSE REACTIONS and PRECAUTIONS.) DELAY IN PROPER MANAGEMENT OF DOSE-RELATED TOXICITY, UNDERVENTILATION FROM ANY CAUSE, AND/OR ALTERED SENSITIVITY MAY LEAD TO THE DEVELOPMENT OF ACIDOSIS, CARDIAC ARREST, AND, POSSIBLY, DEATH.
It is essential that aspiration for blood or cerebrospinal fluid, where applicable, be done prior to injecting any local anesthetic, both the original dose and all subsequent doses, to avoid intravascular or subarachnoid injection. However, a negative aspiration does not ensure against an intravascular or subarachnoid injection.
Reactions resulting in fatality have occurred on rare occasions with the use of local anesthetics, even in the absence of a history of hypersensitivity. Large doses of local anesthetics should not be used in patients with heartblock.
NOVOCAIN with epinephrine or other vasopressors should not be used concomitantly with ergot-type oxytocic drugs, because a severe persistent hypertension may occur. Likewise, solutions of NOVOCAIN containing a vasoconstrictor, such as epinephrine, should be used with extreme caution in patients receiving monoamine oxidase inhibitors (MAOI) or antidepressants of the triptyline or imipramine types, because severe prolonged hypertension or disturbances of cardiac rhythm may occur.
Local anesthetic procedures should be used with caution when there is inflammation and/or sepsis in the region of the proposed injection.
Mixing or the prior or intercurrent use of any local anesthetic with NOVOCAIN cannot be recommended because of insufficient data on the clinical use of such mixtures.
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 and ADVERSE REACTIONS.) 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. Injections should be made slowly, with frequent aspirations before and during the injection to avoid intravascular injection. Current opinion favors fractional administration with constant attention to the patient, rather than rapid bolus 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.
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 severe disturbances of cardiac rhythm, shock, heartblock, or hypotension.
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, light-headedness, 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 circumscribed quantities in areas of the body supplied by end arteries, or those areas having otherwise compromised blood supply such as digits, nose, external ear, penis. Patients with peripheral vascular disease and hypertensive vascular disease may exhibit an exaggerated vasoconstrictor response. Ischemic injury or necrosis may result.
NOVOCAIN should be used with caution in patients with known allergies and sensitivities. A thorough history of the patient’s prior experience with NOVOCAIN or other local anesthetics as well as concomitant or recent drug use should be taken. (See CONTRAINDICATIONS and WARNINGS.)
Because ester-type local anesthetics such as NOVOCAIN are hydrolyzed by plasma cholinesterase produced by the liver and excreted by the kidneys, these drugs, especially repeat doses, should be used cautiously in patients with hepatic disease. Because of their inability to metabolize local anesthetics normally, patients with severe hepatic disease 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 conduction of anesthesia are considered potential triggering agents for familial malignant hyperthermia. Because it is not known whether ester-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 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 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 intra-arterial injection of the local anesthetic with retrograde flow to the cerebral circulation. 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.
Information for Patients:
When appropriate, patients should be informed, in advance, that they may experience temporary loss of sensation and motor activity following proper administration of regional anesthesia. Also, when appropriate, the physician should discuss other information including adverse reactions in the package insert.
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.
The clinical observation has been made that despite adequate sulfonamide therapy, local infections have occurred in areas infiltrated with procaine hydrochloride prior to diagnostic punctures and drainage procedures. Therefore, NOVOCAIN should not be used in any condition in which a sulfonamide drug is being employed since para-aminobenzoic acid inhibits the action of the sulfonamide.
Carcinogenesis, Mutagenesis, and Impairment of Fertility:
Long-term studies in animals of most local anesthetics, including procaine hydrochloride, to evaluate the carcinogenic potential have not been conducted. Mutagenic potential or the effect on fertility have not been determined. There is no evidence from human data that NOVOCAIN may be carcinogenic, or mutagenic, or that it impairs fertility.
Pregnancy Category C:
Animal reproduction studies have not been conducted with NOVOCAIN. It is not known whether procaine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. NOVOCAIN should be given to a pregnant woman only if clearly needed and the potential benefits outweigh the risk. This does not exclude the use of procaine hydrochloride at term for obstetrical anesthesia or analgesia. (See Labor and Delivery.)
Labor and Delivery:
Local anesthetics rapidly cross the placenta, and when used for paracervical or pudendal block anesthesia, can cause varying degrees of maternal, fetal, and neonatal toxicity. (See CLINICAL PHARMACOLOGY.) 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.
Paracervical or pudendal anesthesia may alter the forces at parturition through changes in uterine contractility or maternal expulsive efforts. In one study, paracervical block anesthesia was associated with a decrease in the mean duration of first stage labor and facilitation of cervical dilation. 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. The long-term significance of these observations is unknown.
Fetal bradycardia which frequently follows paracervical block may be indicative of high fetal blood concentrations of procaine with resultant fetal acidosis. Fetal heart rate should be monitored prior to and during paracervical block. Added risk appears to be present in prematurity, toxemia of pregnancy, and fetal distress. The physician should weigh the considering paracervical block in these conditions. Careful adherence to recommended dosage is of the utmost importance in paracervical block. Failure to achieve adequate analgesia with these doses should arouse suspicion of intravascular or fetal injection.
Cases compatible with unintended fetal intracranial injection of local anesthetic solution have been reported following intended paracervical or pudendal block or both. Babies so affected present with unexplained neonatal depression at birth, which correlates with high local anesthetic serum levels, and usually manifest seizures within six hours. Prompt use of supportive measures combined with forced urinary excretion of the local anesthetic has been used successfully to manage this complication.
Case reports of maternal convulsions and cardiovascular collapse following use of some local anesthetics for paracervical block in early pregnancy (as anesthesia for elective abortion) suggest that systemic absorption under these circumstances may be rapid. The recommended maximum dose of the local anesthetic should not be exceeded. Injection should be made slowly and with frequent aspiration. Allow a five-minute interval between sides.
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 the gravid uterus displaced to the left.
Nursing Mothers:
It is not known whether local anesthetic drugs are excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when local anesthetics are administered to a nursing woman.
Pediatric Use:
(See DOSAGE AND ADMINISTRATION.)
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