Abstract
Background
Methemoglobinemia is a well-recognized adverse drug reaction related to the use of
certain local anesthetic agents. The mainstay of treatment for methemoglobinemia is
i.v. methylene blue, along with provision of supplemental oxygen; however, methylene
blue is listed as a category X teratogen. This poses an issue should methemoglobinemia
develop during pregnancy.
Case Report
A 35-year-old, 20-week and 5-day gravid female was transferred from an outpatient
oral surgeon's office for hypoxia. She was undergoing extraction of 28 teeth and was
administered an unknown, but “large” quantity of prilocaine during the procedure.
Given this exposure, the concern was for methemoglobinemia. This was confirmed with
co-oximetry, which showed 34.7% methemoglobin. The initial treatment plan was methylene
blue; however, this drug is a category X teratogen. Thus, an interdisciplinary team
deliberated and decided on treatment with high-dose ascorbic acid and transfusion
of a single unit of packed red blood cells. The patient was managed with noninvasive
ventilation strategies and a total of 8 g ascorbic acid. She was discharged on hospital
day 3 with no obstetric issues noted.
Why Should an Emergency Physician Be Aware of This?
Intravenous ascorbic acid appears to be a potential alternative to methylene blue
in this patient population. The data surrounding teratogenicity of methylene blue
are mostly related to intra-amniotic or intra-uterine administration. In life-threatening
cases of methemoglobinemia during pregnancy, the benefits of i.v. methylene blue may
outweigh the risks.
Keywords
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References
- Methemoglobinemia: pathogenesis, diagnosis, and management.South Med J. 2011; 104: 757-761
- Methemoglobinemia related to local anesthetics: a summary of 242 episodes.Anesth Analg. 2009; 108: 837-845
- Methylene blue. LexiComp Online, Lexi-Drugs. Lexi-Comp, Inc., Hudson, OH2017
- Benzocaine-induced methemoglobinemia based on the Mayo Clinic experience from 28,478 transesophageal echocardiograms: incidence, outcomes, and predisposing factors.Ann Intern Med. 2007; 167: 1977-1982
- Acquired methemoglobinemia: a retrospective series of 138 cases at 2 teaching hospitals.Medicine (Baltimore). 2004; 83: 265-273
- Prilocaine. LexiComp Online, Lexi-Drugs. Lexi-Comp, Inc., Hudson, OH2017
- Drug-induced methaemoglobinemia: treatment issues.Drug Saf. 1996; 14: 394
- Consequences of methemoglobinemia in pregnancy in newborns, children, and adults: issues raised by new finding on methemoglobin catabolism.J Matern Fetal Neonatal Med. 2010; 9: 956-959
- Rare case of methemoglobinemia complicating pregnancy.Case Rep Obstet Gynecol. 2016; 2016: 9740403
- Methylene blue: revisited.J Anaesthesiol Clin Pharmacol. 2010; 26: 517-520
- Teratogen update: methylene blue.Teratology. 1999; 60: 42-48
- Methylene-blue-induced hemolytic anemia in a neonate.Can Med Assoc J. 1987; 136: 503-504
- Methylene blue-induced phototoxicity: an unrecognized complication.Pediatrics. 1996; 97: 717-721
- A cautionary tale: intra amniotic injection of methylene blue.Ceylon Med J. 2000; 45: 44-45
- Laparoscopy and methylene blue intrauterine injection immediately after undiagnosed conception: effect on pregnancy and neonatal outcome.Eur J Obstet Gynecol Reprod Biol. 2004; 112: 102-103
- Are there teratogenic risks associated with antidotes used in the acute management of poisoned pregnant women?.Birth Defects Res A Clin Mol Teratol. 2003; 67: 133-140
- Methylene blue-induced hyperbilirubinemia in neonatal glucose-6-phosphate dehydrogenase (G6PD) deficiency.J Matern Fetal Med. 2000; 9: 252-254
- Pharmacokinetics of methylene blue dye for lymphatic mapping in breast cancer—implications for use in pregnancy.Am J Surg. 2011; 201: 70-75
- I.V. ascorbic acid for treatment of apparent rasburicase-induced methemoglobinemia in a patient with acute kidney injury and assume glucose-6-phosphate dehydrogenase deficiency.Am J Health Syst Pharm. 2016; 73: e238-e242
- High-dose vitamin C management in dapsone-induced methemoglobinemia.Am J Emerg Med. 2014; 32: 684
- Vitamin C pharmacokinetics: implications for oral and intravenous use.Ann Intern Med. 2004; 140: 533-537
Article info
Publication history
Published online: March 05, 2018
Accepted:
January 25,
2018
Received in revised form:
October 4,
2017
Received:
July 5,
2017
Identification
Copyright
© 2018 Elsevier Inc. All rights reserved.
