Methemoglobinemia is a potentially severe complication of lidocaine and benzocaine, especially when used concomitantly. Learn more about methemoglobinemia, betaglobin type, causes, symptoms, and genes. A longknown side effect of benzocaine, methemoglobinemia happens when oxygen levels in the blood drop dangerously low. Fda warns benzocaine teething products are unsafe for. Methemoglobinemia an overview sciencedirect topics. Increased levels of methemoglobin in the blood are secondary to congenital. Benzocaine and lidocaine induced methemoglobinemia after. Benzocaineinduced methemoglobinemia is a rare complication associated with topical anesthesia and can be lifethreatening.
The agent of choice depends on the method of administration, the. A 47yearold female with medical history of vulvar cancer and hiv undergoing chemoradiation was sent by the oncology. Methemoglobinemia is lifethreatening and bears pathognomonic signs difficult to diagnose in real time. Methemoglobinemia methba is a clinical syndrome caused by an increase in the blood levels of methemoglobin methb 1 secondary to both congenital chronic changes in hemoglobin hb synthesis or metabolism, or acute imbalances in reduction and oxidation reactions redox imbalance induced by the exposure to several chemical agents 2,3. Methemoglobinemia methb is a blood disorder in which an abnormal amount of methemoglobin is produced. Topical benzocaine associated with methemoglobinemia. Local anesthetics are widely used and are known for eliciting this condition. Although, as reported in the adult population, it happens most often due to prescribed medication or procedural anesthesia and not due to easily accessed overthecounter medications, the authors will describe an otherwise healthy male adult with. Benzocaine, a commonly used topical anesthetic employed in multiple products, has been associated with methemoglobinemia. This results in a decreased availability of oxygen to the tissues. Benzocaine has been implicated in a majority of cases and has been removed from some hospital formularies. Topical anestheticinduced methemoglobinemia advisory.
Few such reports of benzocaineinduced methemoglobinemia are available in the englishlanguage cardiology literature. Reported adverse event cases of methemoglobinemia associated with benzocaine products. Acquired methemoglobinemia is a known complication of topical anesthesia during endoscopic procedures. Although it occurs infrequently, benzocaineinduced methemoglobinemia is a potentially fatal complication if not promptly diagnosed and treated.
A single spray of benzocaine may induce methemoglobinemia. Acute methemoglobinemia induced by topical benzocaine and. He developed central cyanosis and his oxygen saturation was 85% via pulse oximetry. Differences in absorption and metabolism may explain the variability of benzocaineinduced methemoglobinemia in these individuals. Rebound methemoglobinemia may occur up to 18 hours after mb administration, due to prolonged absorption of lipophilic agents benzocaine from adipose tissue. Acutely developing methemoglobinemia is infrequently. A healthy 14 month infant developed severe cyanosis 2030 minutes after topical application of a benzocaine containing gel administered for relief of. The order also included instructions to repeat the spray every six hours for pain relief. Acute methemoglobinemia may result from the use of several local anesthetic agents. Methemoglobinemia, betaglobin type, is a rare inherited disorder that disrupts the function of hemoglobin, the molecule in red blood cells that delivers oxygen throughout the body. Collins portland veterans administration medical center and oregon health sciences university department of medicine, division of gastroenterology, portland, oregon topical 20% benzocaine hurricaine, beutlich, inc. A 46yearold woman with a medical history of hypertension, anemia, depression, and morbid obesity which persisted after a gastric bypass in 2003 presented on april 3, 20, for laparoscopic fistula repair and revision of her 2003 gastric bypass. Methemoglobinemia congenital or acquired occurs when red blood cells rbcs contain methemoglobin at levels higher than 1%.
Acquired methemoglobinemia typically results from ingestion of specific drugs or agents that cause an increase in the production of methemoglobin. We report a case of methemoglobinemia secondary to selfadministered use of benzocaine spray. In addition to a functional anemia, methhemoglobinemia causes the o2binding affinity of the remaining o2 sites in the hemoglobin tetramer to increase. The following report describes a patient with benzocaineinduced methemoglobinemia who was seen at our hospital. Benzocaine overthecounter products can increase the risk. A 62yearold male underwent bronchoscopy where lidocaine oral solution and hurricaine spray 20% benzocaine were used. Methemoglobinemia from topical benzocaine cleveland. Severe methemoglobinemia complicating topical benzocaine use. Inappropriate use of benzocaine sprays linked to risk for. Methemoglobinemia definition of methemoglobinemia by. The most common medications that have been linked to acquired methemoglobinemia are local anesthetics lidocaine, prilocaine, and benzocaine and dapsone, an agent that has been used for the treatment and prevention of pneumocystis jiroveci pcp infection. A case is reported in which a patient developed methemoglobinemiainduced cyanosis while under general anesthesia during surgery for multiple fascial space infections. Drugs implicated more often include local anesthetics benzocaine, lidocaine, and.
Methemoglobinemia should be considered in any patient who demonstrates cyanosis, respiratory distress, headache, lightheadedness, and a dark, chocolate. Patients may remain asymptomatic with significant levels of methemoglobin. Abstractacute cyanosis and methemoglobinemia developed following topical application and partial ingestion of benzocaine for esophagogastroduodenoscopy. A diagnosis of acute toxic methemoglobinemia should be considered when cyanosis, with or without neurologic symptoms, occurs following the use of local anesthetics in the absence of cardiopulmonary disease. Reported adverse event cases of methemoglobinemia associated. Benzocaine cetacaine spray has been shown previously to cause methemoglobinemia in two patients when applied topically to the mucous membranes. Diagnosis of methemoglobinemia in cats you should take your cat to a veterinarian as soon as possible after spotting these dangerous symptoms, as methemoglobinemia is a lifethreatening condition. Benzocaine lawsuit methemoglobinemia lawyer, attorney. Methemoglobinemia should be considered in any patient who demonstrates cyanosis, respiratory distress, headache, lightheadedness, and a dark, chocolatecolored blood after receiving pharyngeal anesthesia. Among the acquired causes of methemoglobinemia, although caineinduced methemoglobinemia is rare, it may have a fatal outcome. Acquired methemoglobinemia is caused by an external source, usually a drug or medication. Recent warnings from health canada have highlighted the risk of methemoglobinemia with benzocaine, 1 but this rare and potentially serious adverse effect can occur with a number of other medications. Topical benzocaineinduced methemoglobinemia in the pediatric population.
Acquired methemoglobinemia is an uncommon hemoglobinopathy that results from exposure to oxidizing agents, such as chemicals or medications. Risk of acquired methemoglobinemia with different topical. Hemoglobin is the protein in red blood cells rbcs that carries and distributes oxygen to the body. We present a case of recurrent methemoglobinemia because of occult use of topical benzocaine to the vulva. Then you can start reading kindle books on your smartphone, tablet, or computer. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Here we report a case of severe acquired methemoglobinemia resulting from topical use of benzocaine spray during diagnostic upper gastrointestinal. Methylene blue intravenously is the treatment of choice to reduce methemoglobinemia.
Benzocaineinduced methemoglobinemia based on the mayo clinic experience from 28 478 transesophageal echocardiograms. Methemoglobinemia in cats symptoms, causes, diagnosis. It is also combined with antipyrine to form ab otic drops to relieve ear pain and remove earwax. When induced by benzocaine anesthetic spray and other chemicals, it can result in cyanosis. It is the active ingredient in many overthecounter anesthetic ointments such as products for oral ulcers. This book is distributed under the terms of the creative commons attribution.
Benzocaine has been implicated in a majority of cases and has been. These medications can inhibit the bodys systems of reducing methemoglobin to hemoglobin resulting in methemoglobinemia. Methemoglobinemia results from oxidation of ferrous to ferric iron in hemoglobin. Increased levels of methemoglobin results in functional anemia. Methemoglobinemia as a complication of 20% benzocaine.
Some of these medications include benzocaine, lidocaine and prilocaine. Through march 16, 2011, a total of 21 cases of methemoglobinemia associated with the use of overthecounter benzocaine gel or liquid products were reported to. Benzocaine ethyl aminobenzoate, used routinely as a topical oropharyngeal anesthetic for transesophageal echocardiography tee, has been reported to rarely cause methemoglobinemia. Methemoglobin mehb is hemoglobin hb containing oxidized rather than oxygenated iron. Tetracaine is rapidly absorbed from the respiratory and gastrointestinal tract when used to anesthetize. For this reason, the veterans health administration va announced on february 8, 2006, that they would stop using benzocainecontaining sprays for procedures involving the mouth and throat.
Methemoglobinemia is a common adverse effect of prilocaine see also benzocaine above. Methemoglobinemia and benzocaine article nursingcenter. Signs and symptoms of methemoglobinemia associated with use of topical benzocaine may include cyanosis, headache, lightheadedness, shortness of breath, fatigue, lethargy, tachycardia, fainting, and even death. Physicians should consider treating methemoglobinemia if the patient is symptomatic or the methemoglobin concentration rises to 30%. Lawyers evaluated consumer lawsuits against benzocaine product manufacturers who didnt properly warn the public. Methemoglobinemia, betaglobin type, is caused by a mutation in the hbb gene. A 27yearold woman was found to be in respiratory distress during postoperative recovery.
Developing countries regional anesthesia lecture series. Fda will continue to evaluate the risk of methemoglobinemia associated with benzocaine and provide updated information as necessary. Methemoglobinemia is a rare cause of hypoxemia, characterized by abnormal levels of oxidized hemoglobin that cannot bind to and transport oxygen. Enter your mobile number or email address below and well send you a link to download the free kindle app. Benzocaine spray is a local anesthetic commonly used for topical anesthesia of mucous membranes before endoscopic procedures. H ealthcare professionals know that intravenous or inhaled anesthetics are not innocuous substances. Any benzocaine products marketed to these patient populations will be removed from the market by fda. Cover to cover, gastroenterology nursing delivers the information nurses need to stay. Methemoglobinemia is a rare condition in which the iron in hemoglobin is. Pdf methemoglobinemia due to topical pharyngeal anesthesia. Gastroenterology nursing september october 2007 vol. Acquired methemoglobinemia is a known complication of topical anesthesia during. We report a case of methemoglobinemia after topical use of benzocaine in. We describe a 4yearold girl who received a standard dose of topical benzocaine to her gastrostomy mucosa that resulted in rapid, severe methgb.
In a retrospective cohort study of 50 children aged 331 months undergoing infiltration anesthesia of the scalp before craniofacial surgery, lidocaine 1% with adrenaline caused this complication in. Methemoglobin results from the presence of iron in the ferric form instead of the usual ferrous form. The cause of methemoglobinemia was 20% benzocaine spray used for local anesthesia before intubation. The fda warned consumers and sent letters to manufacturers to stop selling overthecounter teething products, such as orajel, that contain benzocaine. The fda recommends not using benzocaine products in children younger than 2 years without medical supervision. Risk of acquired methemoglobinemia with different topical anesthetics during endoscopic procedures srikanth vallurupalli1, shalini manchanda21division of general internal medicine, department of medicine, southern illinois university school of medicine, springfield, il, usa. Methemoglobinemia can cause lifethreatening hypoxia associated with cyanosis and dyspnea not responsive to oxygen. A standardized methemoglobinemia warning will also be added to prescription local anesthetics. Benzocaine sprays, gels, and liquids, used as anesthesia during medical procedures and as a treatment for tooth and gum pain, have been associated with a serious and potentially fatal blood disorder called methemoglobinemia. Benzocaine is a common topical anesthetic that has the ability to induce methemoglobinemia methgb in large doses. Incidence of methemoglobinemia in patients receiving cerium nitrate and silver sulfadiazine for the treatment of burn wounds. She required intubation, mechanical ventilation, and multiple doses of methylene blue for treatment.
60 327 894 353 1126 171 443 11 946 1151 1082 1062 125 10 1118 1308 1040 227 786 363 522 700 1385 46 1159 1382 666 1424 271 1113 653 800 416 914 375 258