Lidocaine application to oral mucosa can interfere with swallowing and increase the risk of aspiration. Patients should not ingest food for at least 1 hour after the use of anesthetic agents in the mouth or throat.
Local anesthetics, like lidocaine, should only be administered by a clinician trained in the diagnosis and management of drug-related toxicity and other acute emergencies that might arise from the administration of a regional anesthetic block. The immediate availability of oxygen, cardiopulmonary resuscitative equipment and drugs and the appropriate support personnel for the management of toxic reactions or emergencies must be ensured. Any delay in appropriate management may lead to the development of acidosis, cardiac arrest, and possibly death.
Lidocaine is contraindicated in patients with amide local anesthetic hypersensitivity. Parenteral preparations containing preservatives should not be used for spinal or epidural anesthesia. Solutions containing dextrose may be contraindicated in patients with known allergy to corn or corn products. There have been no reports of cross-sensitivity between lidocaine and either procainamide or quinidine.
Lidocaine does not provide adequate anesthesia in patients with collagen-vascular disease, such as Ehlers Danlos Type III. Lidocaine is relatively contraindicated in these conditions.
Methemoglobinemia has been reported with local anesthetic use. Although all patients are at risk for methemoglobinemia, patients with glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency), preexisting (congenital or idiopathic) methemoglobinemia, cardiac or pulmonary compromise (cardiac disease or pulmonary disease), those younger than 6 months, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing methemoglobinemia. Monitor such patients closely for signs and symptoms of methemoglobinemia if a local anesthetic must be used. Signs of methemoglobinemia may occur immediately or may be delayed hours after exposure. Immediately discontinue the local anesthetic to avoid serious central nervous system and cardiovascular adverse events, as methemoglobin concentrations may continue to rise. Patients may require supportive care such as oxygen therapy and hydration. More severe symptoms may require treatment with methylene blue, exchange transfusion, or hyperbaric oxygen.
Use lidocaine with caution in patients at increased risk of adverse events. Conditions that reduce hepatic blood flow such as hepatic disease and congestive heart failure may reduce hepatic metabolism and lead to drug accumulation, increasing the risk of developing systemic toxicity, particularly with parenteral, prescription topical jelly, or transdermal patch use. Resuscitative equipment and facilities should be readily available in case of an emergency when using parenteral products. Repeated doses of parenteral lidocaine may cause a significant increase in blood concentrations with each successive dose; these increases may be poorly tolerated, particularly by those who are debilitated, pediatric patients, geriatric patients, or the acutely ill. Excessive dosing by applying lidocaine transdermal patches to larger areas or for longer than the recommended wearing time could result in increased absorption of lidocaine and high blood concentrations, leading to serious systemic adverse effects. Lidocaine toxicity could be expected at lidocaine blood concentrations above 5 mcg/mL. The blood concentration of lidocaine is determined by the rate of systemic absorption and elimination. Longer duration of transdermal application, application of more than the recommended number of patches, smaller patients, or impaired elimination may all contribute to increasing the blood concentration of lidocaine. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents of long-term care facilities. The OBRA guidelines caution that antiarrhythmics can have serious adverse effects (e.g., impairment of mental function, appetite, behavior, heart function, or falls) in older individuals.
Lidocaine is classified as FDA pregnancy category B. Reproductive studies conducted in rats have not demonstrated lidocaine-induced fetal harm; however, animal studies are not always predictive of human response. There are no adequate or well controlled studies of lidocaine in pregnant women. Local anesthetics are known to cross the placenta rapidly and, when administered for epidural, paracervical, pudendal, or caudal block anesthesia, and to cause fetal toxicity. The frequency and extent of toxicity are dependent on the procedure performed. Maternal hypotension can result from regional anesthesia, and elevating the feet and positioning the patient on her left side may alleviate this effect. Topical ocular application of lidocaine is not expected to result in systemic exposure. When lidocaine is used for dental anesthesia, no fetal harm has been observed; lidocaine is generally the dental anesthetic of choice during pregnancy and guidelines suggest the second trimester is the best time for dental procedures if they are necessary. A study by the American Dental Association provides some evidence that, when needed, the use of dental local or topical anesthetics at 13 weeks to 21 weeks of pregnancy or later is likely safe and does not raise incidences of adverse pregnancy outcomes or other adverse events; the study analyzed data from the Obstetrics and Periodontal Therapy (OPT) trial, a multicenter study of over 800 pregnant patients in the early to mid second trimester who received required dental procedures.
According to the manufacturers, caution should be exercised when lidocaine is administered to breastfeeding women (regardless of dosage formulation). Lidocaine is excreted in breast milk with a milk:plasma ratio of 0.4. Many specific dosage forms, including Lidoderm brand lidocaine transdermal patches, have not been studied in breastfeeding women. The American Academy of Pediatrics lists lidocaine as usually compatible with breastfeeding. When lidocaine is used for dental or short-term, limited local anesthesia, the healthy term infant can generally safely nurse as soon as the mother is awake and alert. Consider the benefits of breastfeeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breastfeeding infant experiences an adverse effect related to a maternal drug exposure, healthcare providers are encouraged to report the adverse effect to the FDA.
Although specific forms of parenteral lidocaine are indicated for the treatment of some cardiac arrhythmias, it can worsen others. Intravenous (IV) lidocaine for the treatment of ventricular arrhythmias is contraindicated in patients with Adams-Stokes syndrome, Wolff-Parkinson-White syndrome, or with severe SA block, AV block, or intraventricular heart block. The administration of IV lidocaine for the elimination of ventricular ectopic beats to patients with bradycardia or incomplete heart block without prior acceleration of heart rate may cause a more serious ventricular arrhythmia or complete heart block. Lidocaine can increase the ventricular rate in patients with atrial fibrillation or atrial flutter. Use lidocaine with caution in patients with hypovolemia. Monitor blood pressure and the electrocardiogram during IV lidocaine administration. Promptly discontinue the infusion if signs of excessive depression of cardiac conductivity occur, such as prolongation of the PR interval, widening of the QRS interval, or appearance or aggravation of arrhythmias. Use both parenteral and topical formulations of lidocaine with caution in patients with severe shock (including cardiogenic shock and hemorrhagic shock) and heart block. Patients with impaired cardiac function, particularly AV block, may be less able to compensate for functional changes associated with prolonged AV conduction (i.e., PR or QT prolongation) caused by local anesthetics. Topical ocular application of lidocaine is not expected to result in systemic exposure.
No lidocaine dosage adjustment needed in patients with renal impairment. However, the elimination of glycine xylidide (major active metabolite) is eliminated renally, and accumulation of the metabolite in severe renal failure (renal disease) theoretically could result in neurotoxicity.
Applying dermal, transdermal, or oromucosal lidocaine preparations to severely traumatized skin (e.g.,mucosal or skin abrasion, eczema, burns), to large surface areas, or to warm skin (i.e., exercise, or application of thermal heat wraps or a heating pad immediately before or during topical lidocaine use) can increase its absorption, possibly increasing the risk of systemic toxicity. Also, applying large amounts of lidocaine or using an occlusive dressing (skin wraps) can increase absorption. Patches and administration via Zingo injection system should only be used on intact skin, and transoral delivery systems should only be applied to intact mucosa. Excessive dosing by applying patches to larger areas or for longer than the recommended wearing time could result in increased absorption of lidocaine. Application of one additional Zingo at a new location is acceptable after a failed attempt at venous access. However, multiple administrations of Zingo at the same location are not recommended. Multiple Zingo applications could result in plasma concentrations that could produce systemic toxicity. At least 2 reports of deaths exist after application of topical anesthetics prior to cosmetic procedures. In both instances, women, aged 22 and 25 years, applied topical anesthetics to their legs and wrapped the treated area, as directed, in plastic wrap to enhance the numbing effect of the cream. Both women died from toxic effects of the topical anesthetic. The preparations used in both cases were compounded in pharmacies and contained high amounts of lidocaine and tetracaine. In order to reduce the risk of toxicity due to increased absorption of topical anesthetic, the FDA recommends patients use a topical anesthetic containing the lowest amount of medication needed to relieve pain, apply the medication sparingly, and only treat known or anticipated areas of pain. Further, do not apply the anesthetic to broken or irritated skin, be aware of potential adverse reactions, and do not cover or apply heat to the treated area.
Avoid unintended ocular exposure of lidocaine dermal, oromucosal, and transdermal products. Severe eye irritation has been reported in animals treated with similar products. If eye contact occurs, immediately wash the eye with water or saline and protect the eye until sensation returns. Lidocaine ophthalmic gel is intended for application to the eye surface; however, prolonged use may produce permanent corneal opacification and ulceration with accompanying visual loss. Use with caution in patients with pre-existing cataracts or ocular trauma or ulceration.
To avoid accidental exposure and/or ingestion, advise patients and/or their caregivers to store and dispose of all lidocaine products out of the reach of any pediatric-age person and pets. It is important to note that whether new or used, lidocaine patches contain a large amount of lidocaine (at least 665 mg post-use). The potential exists for small kids or pets to suffer serious adverse reactions from unintended lidocaine exposure including chewing or ingesting a new or used lidocaine patch.
When parenteral lidocaine is intended as a local anesthetic, avoid intravenous administration, intraarterial administration, or intrathecal administration. Unintended intravenous or intraarterial administration may result in cardiac arrest and may require prolonged resuscitation. Further, do not administer preservative-containing parenteral lidocaine via intrathecal routes. To avoid intravascular administration of lidocaine during local anesthetic procedures, aspiration should be performed before the local anesthetic is injected and after repositioning of the needle. During epidural administration, a test dose should be administered initially and the patient should be monitored for CNS and cardiovascular toxicity, as well as signs of inadvertent intrathecal administration (see Adverse Reactions). Syringe aspiration should also be performed before and during each supplemental injection in continuous catheter techniques. Clinicians should be aware that the absence of blood return does not guarantee that intravascular injection has been avoided.
Patients receiving local head and neck anesthesia including retrobulbar, stellate ganglion, and dental blocks, are at increased risk of CNS toxicity similar to the systemic toxicity seen with unintentional intravascular injections of large doses of lidocaine. These reactions may be due to potential intraarterial injection of the local anesthetic with retrograde flow to the cerebral circulation. Patients receiving these blocks should have their ventilatory and circulatory systems monitored closely. Recommended doses should not be exceeded in these patients.
When local anesthetics, like lidocaine, are used for retrobulbar block during ocular surgery, lack of corneal sensation should not be relied upon to determine whether or not the patient is ready for surgery. Lack of corneal sensation usually precedes clinically acceptable external ocular muscle akinesia.
Parenteral use of lidocaine requires an experienced clinician and requires a specialized care setting. Lidocaine preparations containing preservatives should not be used for epidural or spinal anesthesia. Patients with the following conditions should receive spinal anesthesia with caution: pre-existing CNS disorders such as poliomyelitis, pernicious anemia, paralysis from nerve injuries or syphilis; children < 16 years, or elderly patients; chronic backache; preoperative headache; hypotension; hypertension; arthritis or spinal deformity; technical problems (persistent paresthesias, persistent bloody tap); psychotic or uncooperative patients. Consult standard textbooks for specific techniques and precautions for spinal anesthetic procedures. Epidural, local, nerve block and spinal administration of lidocaine are contraindicated in patients with the following: infection or inflammation at the injection site, bacteremia (sepsis), platelet abnormalities, thrombocytopenia less than 100,000/mm3, increased bleeding time, uncontrolled coagulopathy or bleeding, or anticoagulant therapy. Lumbar and caudal epidural anesthesia should be used with extreme caution in patients with existing neurological disease, spinal deformities, sepsis, and severe hypertension. Use caution when applying topical lidocaine to mucous membranes in the presence of sepsis due to the potential for rapid systemic absorption. Patients with platelet disorders or those with bleeding tendencies may be at risk for superficial dermal bleeding when lidocaine is administered intradermally for topical anesthesia.
During labor and obstetric delivery, local anesthetics, like lidocaine, can cause varying degrees of maternal, fetal, and neonatal toxicities. The potential for toxicity is related to the procedure performed, the type and amount of drug used, and the technique of administration. Appropriate patient positioning during obstetric delivery may decrease maternal hypotension that can result from regional anesthesia. Injection of the local anesthetic should be performed with the patient in the left lateral decubitus position to displace the gravid uterus, thereby minimizing aortocaval compression. Epidural, spinal, paracervical, or pudendal nerve block may alter the forces of parturition. The use of obstetrical anesthesia may alter the duration of various phases of labor and increase the need for forceps assistance. Electronic fetal monitoring for signs of fetal distress is highly recommended.
Lidocaine is not approved for continuous intraarticular infusion administration. Infusion of local anesthetics into a joint space may have caused chondrolysis (see Adverse Reactions). Local anesthetics are not indicated for continuous intraarticular postoperative infusions or for use with infusion devices such as elastomeric pumps.
Physicians should weigh the possible risks versus benefits when considering obstetrical paracervical nerve block with parenteral lidocaine in situations of fetal prematurity, toxemia of pregnancy, and fetal distress. Adherence to the recommended dosage is critical during obstetrical paracervical block. Failure to achieve adequate analgesia with recommended doses should arouse suspicion of intravascular or fetal intracranial injection. Use of paracervical block in early pregnancy (i.e., anesthesia for elective abortion) may result in rapid systemic absorption and can result in maternal seizures or cardiovascular collapse. The recommended dose of the local anesthetic should not be exceeded. Injections should be administered slowly with frequent aspirations. Allow a 5-minute interval between administration to each side.
Use lidocaine with caution in patients with a genetic predisposition to malignant hyperthermia. Although it is unknown whether lidocaine triggers this reaction, it is recommended that a standard protocol for management be available when lidocaine is administered in hospital environments.
Lidocaine dosages in pediatric patients should be reduced, commensurate with age, body weight and physical condition. When multiple formulations of lidocaine are used at once, the amount systemically absorbed from all formulations must be considered. Resuscitative equipment and facilities should be readily available in case of an emergency when using parenteral products. Repeated doses of parenteral lidocaine may cause a significant increase in blood concentrations with each successive dose; these increases may be poorly tolerated by pediatric patients, particularly by those who are debilitated or the acutely ill. Similar increases in systemic exposure are possible with repeat topical application. Certain products, such as lidocaine transdermal patches, have not been FDA-approved for application to pediatric patients. Non-prescription (OTC) products should not be used without healthcare professional advice in those under 2 years of age, or as directed on the product label. Do not use lidocaine viscous solution for the treatment of teething pain in infants and young children due to the risk of serious adverse reactions, including seizures, cardiopulmonary arrest, severe brain injury, and death. The FDA reviewed 22 cases of serious adverse events that occurred in infants and young children between 5 months and 3.5 years of age after receiving lidocaine viscous solution for the treatment of mouth pain due to teething or stomatitis or who had accidental ingestions. Of the 22 cases, 6 cases resulted in death, 3 were categorized as life-threatening, 11 required hospitalization, and 2 required medical intervention without hospitalization. The FDA recommends against the use of topical pain relievers for teething pain due to the fact that they wash out of the mouth within minutes of application and can cause serious adverse reactions if they are swallowed in excessive amounts. Advise parents and caregivers with teething pain concerns to follow the American Academy of Pediatrics recommendations for the management of teething pain, which include using a teething ring chilled in the refrigerator (not frozen) and gently rubbing or massaging the gums with a finger. For other conditions, the use of viscous lidocaine in neonates, infants, and children 3 years of age and younger should be limited to those situations where safer alternatives are not available or have failed. To ensure safety, doses should be measured by an accurate device, administered no more often than every 3 hours, used only for the prescribed indication, and stored safely out of the reach of children immediately after use. When topical anesthetics are used in the mouth, the topical anesthesia may impair swallowing and thus enhance the danger of aspiration. For this reason, food should not be ingested for 60 minutes following use of local anesthetic preparations in the mouth or throat area. This is particularly important in children because of their frequency of eating.