Methemoglobinemia induced by combined use of sodium nitrate and acetoaminophen

Systematic Review of Methemoglobinemia in Acetaminophen Poisoning

BACKGROUND

Acetaminophen (N-acetyl-para-aminophenol, paracetamol, (APAP) toxicity is one of the commonly encountered poisonings by emergency physicians. Methemoglobinemia is an uncommon association and rarely seen in APAP poisoning.

METHODS

Retrospective analysis of all the published reports on APAP induced methemoglobinemia from 1968 to 2019.

RESULTS

In total there were 14 cases with 9 females and 6 males. The median age of the study cohort was 59 years. The most common presenting feature was altered mentation (9 patients) followed by cyanosis (3 patients). The intent of consumption was therapeutic (7 cases) versus suicidal (5 cases) attempt.In most cases, the dose of APAP consumption was not known. Aspirin, sulfasalazine, benzocaine spray, nitrate preservative, contaminated water, detergents, etc. where the other agents consumed by the patients in addition to APAP before developing methemoglobinemia. The median MethHb level of the study cohort was 15.85% Patients were treated with NAC, hemodialysis, methylene blue, and ascorbic acid and CRRT in various combinations. Full recovery was seen in 9 patients while 4 patients died.

CONCLUSION

APAP toxicity is a well-known and common entity with multiple sequelae that presents with a variable spectrum of mild to fulminant multiorgan failure. Awareness of non-classical presentations like methemoglobinemia is essential to ensure timely intervention.

General Anesthesia in a Glucose-6-Phosphate Dehydrogenase Deficiency Child: A Case Report

We performed general anesthesia on a 3-year-old boy with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Patients with G6PD deficiency exhibit jaundice and anemia due to hemolysis caused by a lack of the G6PD enzyme. To maintain anesthesia, we used propofol and remifentanil, which may prevent hemolytic attacks by exerting an antioxidant effect. In addition, because the patient was in a high-risk group for the development of methemoglobinemia, we used mepivacaine as a local anesthetic. We liaised with the patient's attending physician to make sufficient arrangements, such as securing an emergency transfer on the day of anesthesia. The patient did not develop hemolytic attacks during or after the procedure, and he progressed well without problems.

Acquired methemoglobinemia from phenazopyridine use

Background

Phenazopyridine-induced methemoglobinemia is relatively rare with fewer than ten cases reported over the past 35 years. We describe a case of phenazopyridine-induced methemoglobinemia that is unique in the way the patient presented and how initial workup was completed.

Case presentation

The patient presented with lethargy, diarrhea, light-headedness, and headaches, with past medical history of breast cancer, seizures, and recent dysuria for which she had been taking phenazopyridine. She was noted to have a persistent hypoxemia despite supplemental oxygen delivery and a shunting process was considered, with pulmonary embolus and methemoglobinemia due to phenazopyridine use being of chief concern. She was stabilized, and confirmation of original diagnosis was made at the main ED and treatment successfully rendered with good effect.

Conclusions

Methemoglobinemia, while rare, can be associated with use of over-the-counter medicines and should be considered as part of a broad differential. This case serves to emphasize the importance of a thorough history and physical—tools especially helpful when at a satellite facility with relatively limited resources.

The Beef Jerky Blues: Methemoglobinemia From Home Cured Meat

Methemoglobinemia can result from ingestion of nitrite- or nitrate-containing foods. Here, we report a case where an adolescent girl and her father developed clinically significant methemoglobinemia after ingestion of "homemade" beef jerky prepared with sodium nitrate salt purchased at a local grocery store. Both had palpitations, dyspnea, and visible mucosal cyanosis. The daughter had a methemoglobin level of 44.2% and the father's methemoglobin level was 34.2%. Prompt recognition of methemoglobinemia is important for initiating antidotal therapy with methylene blue.

[Association of benzocaine and paracetamol with neonatal-acquired methemoglobinemia]

BACKGROUND

Drug-induced acquired methemoglobinemia in the newborn is a rare event; however, when it develops, early diagnosis and proper treatment become paramount because it can evolve rapidly into a particularly serious disease causing permanent brain damage or death.

CASE REPORT

We report a unique case of severe methemoglobinemia that developed in a newborn associated with a minimal application of a benzocaine healing cream to an anal surgical wound while on acetaminophen. In addition to benzocaine as the primary cause in this case, we raise the possibility that acetaminophen-a mild oxidant-increased the susceptibility of the patient to benzocaine, leading to severe clinical methemoglobinemia based on the known immaturity of the enzymatic systems involved in caines and acetaminophen clearance in the newborn. Treatment of methemoglobinemia is reviewed.

CONCLUSIONS

Methemoglobinemia is a serious condition that can be easily induced by the use of oxidant medications in the newborn like local anesthetics. The possibility of unexpected drug to drug interactions, particularly between commonly used medications such as acetaminophen with other methemoglobin-causing agents, must always be kept in mind. Because of the possible deleterious consequences, mandatory labelling of caine-containing local anesthetic creams, gels and sprays with a warning for the likelihood of causing severe methemoglobinemia in children is recommended. Also, prohibiting their use in the newborn becomes mandatory.

Methaemoglobinemia Induced by MDMA?

Case. A 45-year-old man with a blank medical history presented at the emergency room with dizziness and cyanosis. Physical examination showed cyanosis with a peripheral saturation (SpO₂) of 85%, he did not respond to supplemental oxygen. Arterial blood gas analysis showed a striking chocolate brown colour. Based on these data, we determined the arterial methaemoglobin concentration. This was 32%. We gave 100% oxygen and observed the patient in a medium care unit. The next day, patient could be discharged in good condition. Further inquiry about exhibitions and extensive history revealed that the patient used MDMA (3,4- methylenedioxymethamphetamine, the active ingredient of ecstasy). Conclusion. Acquired methaemoglobinemia is a condition that occurs infrequently, but is potentially life threatening. Different nutrients, medications, and chemicals can induce methaemoglobinemia by oxidation of haemoglobin. The clinical presentation of a patient with methaemoglobinemia is due to the impossibility of O₂ binding and transport, resulting in tissue hypoxia. Important is to think about methaemoglobin in a patient who presents with cyanosis, a peripheral saturation of 85% that fails to respond properly to the administration of O₂. Because methaemoglobin can be reduced physiologically, it is usually sufficient to remove the causative agent, to give O₂, and to observe the patient.

Effect of acetaminophen, a cyclooxygenase inhibitor, on Morris water maze task performance in mice

Although the mechanism of action of acetaminophen (AAP) is not fully understood, some studies suggest that AAP and phenacetin (PHE) are selective cyclooxygenase (COX)-3 inhibitors. To examine the participation of COX-3 in memory formation, water maze performance was studied in mice treated with AAP, PHE or other COX inhibitors. Mice received intraperitoneal injections of drugs immediately after each training session. Administration of high-dose AAP [302.3 mg/kg (IC50 for COX-2)] or PHE [179.2 mg/kg (IC50 for COX-2)] and of non-specific (indomethacin: 20 mg/kg) or specific COX-2 (NS-398: 10 mg/kg) inhibitor impaired the performance in hidden platform (HP) not visible platform (VP) tasks, whereas low-dose (15.1 mg/kg) AAP facilitated performance in HP and VP tasks. The facilitation of performance by low-dose AAP was reversed by co-administration with a 5-HT(1/2) receptor antagonist (methysergide: 0.47 mg/kg). The middle-dose [69.5 mg/kg (IC50 for COX-3)] of AAP, the PHE [17.9 mg/kg (IC50 for COX-3)] and a specific COX-1 inhibitor (piroxicam: 10-20 mg/kg) did not influence performance in either task. These results suggest that the memory impairment by high-dose AAP and PHE and facilitation of performance by low-dose AAP could involve endogenous COX-2 and serotonergic neuronal activity, but not COX-3, respectively.