Cover to cover, gastroenterology nursing delivers the information nurses need to stay. Pdf methemoglobinemia due to topical pharyngeal anesthesia. Benzocaine lawsuit methemoglobinemia lawyer, attorney. The fda recommends not using benzocaine products in children younger than 2 years without medical supervision. Methemoglobinemia as a complication of 20% benzocaine. Methemoglobinemia can cause lifethreatening hypoxia associated with cyanosis and dyspnea not responsive to oxygen. A 47yearold female with medical history of vulvar cancer and hiv undergoing chemoradiation was sent by the oncology. In addition to a functional anemia, methhemoglobinemia causes the o2binding affinity of the remaining o2 sites in the hemoglobin tetramer to increase. Methemoglobinemia methb is a blood disorder in which an abnormal amount of methemoglobin is produced. The fda warned consumers and sent letters to manufacturers to stop selling overthecounter teething products, such as orajel, that contain benzocaine. 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.
Methemoglobin results from the presence of iron in the ferric form instead of the usual ferrous form. Benzocaine is a common topical anesthetic that has the ability to induce methemoglobinemia methgb in large doses. A standardized methemoglobinemia warning will also be added to prescription local anesthetics. Benzocaineinduced methemoglobinemia is a rare complication associated with topical anesthesia and can be lifethreatening. It is the active ingredient in many overthecounter anesthetic ointments such as products for oral ulcers. Developing countries regional anesthesia lecture series. Patients may remain asymptomatic with significant levels of methemoglobin. It is also combined with antipyrine to form ab otic drops to relieve ear pain and remove earwax. Methemoglobinemia an overview sciencedirect topics. Increased levels of methemoglobin results in functional anemia.
These medications can inhibit the bodys systems of reducing methemoglobin to hemoglobin resulting in methemoglobinemia. Fda warns benzocaine teething products are unsafe for. Fda will continue to evaluate the risk of methemoglobinemia associated with benzocaine and provide updated information as necessary. 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. Then you can start reading kindle books on your smartphone, tablet, or computer. Here we report a case of severe acquired methemoglobinemia resulting from topical use of benzocaine spray during diagnostic upper gastrointestinal. Acquired methemoglobinemia is a known complication of topical anesthesia during endoscopic procedures. Methemoglobinemia is a rare cause of hypoxemia, characterized by abnormal levels of oxidized hemoglobin that cannot bind to and transport oxygen. 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. Methemoglobin mehb is hemoglobin hb containing oxidized rather than oxygenated iron. When induced by benzocaine anesthetic spray and other chemicals, it can result in cyanosis. Methylene blue intravenously is the treatment of choice to reduce methemoglobinemia. A 27yearold woman was found to be in respiratory distress during postoperative recovery. Lawyers evaluated consumer lawsuits against benzocaine product manufacturers who didnt properly warn the public.
Learn more about methemoglobinemia, betaglobin type, causes, symptoms, and genes. 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. We report a case of methemoglobinemia secondary to selfadministered use of benzocaine spray. After removal of the ng tube, benzocaine 20% topical oral spray hurricaine was ordered, with nursing instructions to apply one spray to the back of the throat. Reported adverse event cases of methemoglobinemia associated.
Methemoglobinemia is lifethreatening and bears pathognomonic signs difficult to diagnose in real time. Acutely developing methemoglobinemia is infrequently. Reported adverse event cases of methemoglobinemia associated with benzocaine products. Risk of acquired methemoglobinemia with different topical. Benzocaine overthecounter products can increase the risk. Methemoglobinemia should be considered in any patient who demonstrates cyanosis, respiratory distress, headache, lightheadedness, and a dark, chocolate. 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. 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. 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. Drugs implicated more often include local anesthetics benzocaine, lidocaine, and. Physicians should consider treating methemoglobinemia if the patient is symptomatic or the methemoglobin concentration rises to 30%. Acute methemoglobinemia induced by topical benzocaine and. Benzocaine, a commonly used topical anesthetic employed in multiple products, has been associated with methemoglobinemia. Acquired methemoglobinemia is a known complication of topical anesthesia during.
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. Differences in absorption and metabolism may explain the variability of benzocaineinduced methemoglobinemia in these individuals. Abstractacute cyanosis and methemoglobinemia developed following topical application and partial ingestion of benzocaine for esophagogastroduodenoscopy. Methemoglobinemia in cats symptoms, causes, diagnosis. Topical anestheticinduced methemoglobinemia advisory. A single spray of benzocaine may induce methemoglobinemia. Ppt infiltration and topical anesthesia powerpoint. Acute methemoglobinemia may result from the use of several local anesthetic agents. Benzocaine spray is a local anesthetic commonly used for topical anesthesia of mucous membranes before endoscopic procedures. Enter your mobile number or email address below and well send you a link to download the free kindle app.
The cause of methemoglobinemia was 20% benzocaine spray used for local anesthesia before intubation. The following report describes a patient with benzocaineinduced methemoglobinemia who was seen at our hospital. Methemoglobinemia results from oxidation of ferrous to ferric iron in hemoglobin. He developed central cyanosis and his oxygen saturation was 85% via pulse oximetry. Rebound methemoglobinemia may occur up to 18 hours after mb administration, due to prolonged absorption of lipophilic agents benzocaine from adipose tissue. Acquired methemoglobinemia typically results from ingestion of specific drugs or agents that cause an increase in the production of methemoglobin. Inappropriate use of benzocaine sprays linked to risk for. Local anesthetics are widely used and are known for eliciting this condition. Severe methemoglobinemia complicating topical benzocaine use. Benzocaine has been implicated in a majority of cases and has been removed from some hospital formularies.
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. Incidence of methemoglobinemia in patients receiving cerium nitrate and silver sulfadiazine for the treatment of burn wounds. Benzocaineinduced methemoglobinemia based on the mayo. We present a case of recurrent methemoglobinemia because of occult use of topical benzocaine to the vulva. Topical benzocaineinduced methemoglobinemia in the pediatric population. This results in a decreased availability of oxygen to the tissues. The order also included instructions to repeat the spray every six hours for pain relief. 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. A longknown side effect of benzocaine, methemoglobinemia happens when oxygen levels in the blood drop dangerously low. Acquired methemoglobinemia is caused by an external source, usually a drug or medication. She required intubation, mechanical ventilation, and multiple doses of methylene blue for treatment. Benzocaine cetacaine spray has been shown previously to cause methemoglobinemia in two patients when applied topically to the mucous membranes. Few such reports of benzocaineinduced methemoglobinemia are available in the englishlanguage cardiology literature.
H ealthcare professionals know that intravenous or inhaled anesthetics are not innocuous substances. Gastroenterology nursing september october 2007 vol. We describe a 4yearold girl who received a standard dose of topical benzocaine to her gastrostomy mucosa that resulted in rapid, severe methgb. Although it occurs infrequently, benzocaineinduced methemoglobinemia is a potentially fatal complication if not promptly diagnosed and treated. 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. The agent of choice depends on the method of administration, the. Methemoglobinemia and benzocaine article nursingcenter. Acquired methemoglobinemia is an uncommon hemoglobinopathy that results from exposure to oxidizing agents, such as chemicals or medications.
Methemoglobinemia congenital or acquired occurs when red blood cells rbcs contain methemoglobin at levels higher than 1%. We report a case of methemoglobinemia after topical use of benzocaine in. Benzocaine, sold under the brand name orajel amongst others, is an ester local anesthetic commonly used as a topical pain reliever or in cough drops. Increased levels of methemoglobin in the blood are secondary to congenital. A 62yearold male underwent bronchoscopy where lidocaine oral solution and hurricaine spray 20% benzocaine were used. Methemoglobinemia is a potentially severe complication of lidocaine and benzocaine, especially when used concomitantly. Hemoglobin is the protein in red blood cells rbcs that carries and distributes oxygen to the body. Methemoglobinemia should be considered in any patient who demonstrates cyanosis, respiratory distress, headache, lightheadedness, and a dark, chocolatecolored blood after receiving pharyngeal anesthesia. Benzocaine ethyl aminobenzoate, used routinely as a topical oropharyngeal anesthetic for transesophageal echocardiography tee, has been reported to rarely cause methemoglobinemia. Methemoglobinemia, betaglobin type, is caused by a mutation in the hbb gene. A case is reported in which a patient developed methemoglobinemiainduced cyanosis while under general anesthesia during surgery for multiple fascial space infections.
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. 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. 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. Some of these medications include benzocaine, lidocaine and prilocaine. Methemoglobinemia is a common adverse effect of prilocaine see also benzocaine above. Benzocaine and lidocaine induced methemoglobinemia after. Tell the vet what symptoms you have observed, when they began, and if your cat has been exposed to any chemicals or been given any medications recently. Methemoglobinemia from topical benzocaine cleveland. With methemoglobinemia, the hemoglobin can carry oxygen, but is not able to release it effectively to. Topical benzocaine associated with methemoglobinemia. Tetracaine is rapidly absorbed from the respiratory and gastrointestinal tract when used to anesthetize. Among the acquired causes of methemoglobinemia, although caineinduced methemoglobinemia is rare, it may have a fatal outcome. Benzocaine has been implicated in a majority of cases and has been.
Any benzocaine products marketed to these patient populations will be removed from the market by fda. This book is distributed under the terms of the creative commons attribution. Benzocaineinduced methemoglobinemia based on the mayo clinic experience from 28 478 transesophageal echocardiograms. 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.
169 247 138 41 1311 393 581 893 490 1641 601 1367 1373 1214 767 207 28 269 303 618 308 607 766 161 637 167 371 25 1501 301 1213 318 1390 1087 474 915 1314 312 492 839 167