The condition is benign. There is no effective treatment for people with a congenital form who develop an acquired form. This means that they should not take drugs such as benzocaine and lidocaine. People who acquire methemoglobinemia from medications can completely recover with proper treatment.

How is methemoglobinemia treated?

Methylene blue is used to treat severe cases of MetHb, and doctors may prescribe ascorbic acid to reduce the level of methemoglobin in the blood. In severe cases, a person may require a blood transfusion or exchange transfusion. Oxygen therapy will also be provided, if required.

What are the long term effects of methemoglobinemia?

Methemoglobinemia, or methaemoglobinaemia, is a condition of elevated methemoglobin in the blood. Symptoms may include headache, dizziness, shortness of breath, nausea, poor muscle coordination, and blue-colored skin (cyanosis). Complications may include seizures and heart arrhythmias.

What is the antidote for methemoglobinemia?

Methylene blue is the most effective antidote for acquired methemoglobinemia. When methylene blue is not available, alternative treatments such as ascorbic acid and hyperbaric oxygen can be useful.

How does vitamin C treat methemoglobinemia?

Vitamin C is recommended for treatment of methemoglobinemia. It has been demonstrated that the reduction of the methemoglobin formation occurs at low vitamin C concentration in mice erythrocytes.

Methemoglobinemia Diagnosis and Treatment

22 related questions found

When is methemoglobin treated?

The diagnosis is confirmed by the level of methemoglobin in blood (1, 6). The treatment with specific antidote is usually recommended in patients with blood methemoglobin level of >20% in symptomatic patients and >30% in asymptomatic patients.

Can methemoglobinemia go away on its own?

The condition is benign. There is no effective treatment for people with a congenital form who develop an acquired form. This means that they should not take drugs such as benzocaine and lidocaine. People who acquire methemoglobinemia from medications can completely recover with proper treatment.

What are the chances of getting methemoglobinemia?

Conclusions and relevance: The overall prevalence of methemoglobinemia is low at 0.035%; however, an increased risk was seen in hospitalized patients and with benzocaine-based anesthetics.

How many cases of methemoglobinemia are there?

Of the 319 cases, 7 were deaths, 32 cases were categorized as life threatening, and 216 were categorized as serious. A review of the 319 cases indicated that the development of methemoglobin emia after treatment with benzocaine sprays may not be related to the amount applied.

How is methemoglobinemia treated in G6PD?

Treatment for methemoglobinemia with intravenous methylene blue is recommended if the blood methemoglobin level is >20%–30%. However, in G6DP deficiency, treatment with methylene blue is contraindicated because the reduction of methemoglobin is NADPH dependent.

How can you get methemoglobinemia?

Most cases of methemoglobinemia are acquired and result from exposure to certain drugs or toxins. One of the more common causes of acquired methemoglobinemia is exposure to topical benzocaine during medical procedures.

Is Sulfhemoglobin irreversible?

Sulfhemoglobin is irreversible, lasting the lifetime of the erythrocyte, and sulfhemoglobin molecules cannot carry oxygen.

How long does it take to develop methemoglobinemia?

The onset of methemoglobinemia is usually within 20 to 60 minutes of drug administration. Normally, 5 g/dL of deoxyhemoglobin (compared with 1.5 g/dL [10%–15%] of methemoglobin) produces noticeable cyanosis.

Who is at risk of methemoglobinemia?

Acquired methemoglobinemia is more frequent in premature infants and infants younger than 4 months, and the following factors may have a role in the higher incidence in this age group: Fetal hemoglobin may oxidize more easily than adult hemoglobin.

Who discovered methemoglobinemia?

Congenital cyanosis due to an abnormal amount of methemoglobin was initially reported early in this century. It was first suggested by Hitzenberger³ in 1932 that this was an inherited metabolic disease. Gibson ⁴ in 1948 identified idiopathic methemoglobinemia as a disease due to an inborn error of metabolism.

Which drug can cause methemoglobinemia?

Drugs that may cause Methemoglobinemia include nitrates derivatives (nitrates salt, nitroglycerin), nitrites derivatives (nitroprusside, amyl nitrite, nitric oxide), sulfonamides, dapsone, phenacetin, phenazopyridine, some local anesthetics such as prilocaine, topical anesthetics such as emla cream, benzocaine, ...

How long does topical benzocaine last?

Benzocaine is a water-insoluble ester-type local anesthetic agent that is mainly useful for topical application. The onset of action is rapid (<1 minute), and the effective duration is 5 to 10 minutes.

Can novocaine cause methemoglobinemia?

Methemoglobinemia is a potentially severe complication of lidocaine and benzocaine, especially when used concomitantly. Among the acquired causes of methemoglobinemia, although caine-induced methemoglobinemia is rare, it may have a fatal outcome.

How can methemoglobinemia be prevented?

Ascorbic acid may also be used to reduce the level of methemoglobin. Alternative treatments include hyperbaric oxygen therapy, red blood cell transfusion and exchange transfusions. In most cases of mild acquired MetHb, no treatment is needed. But you should avoid the medicine or chemical that caused the problem.

Does oral gel cause methemoglobinemia?

FDA further advises that benzocaine oral drug products should only be used in adults and children 2 years and older if they contain certain warnings on the drug label because the local anesthetic benzocaine can cause the life-threatening condition, methemoglobinemia.

Why do nitrates cause methemoglobinemia?

Nitrate in water is almost completely absorbed into the blood. Our bodies convert a portion of that nitrate into nitrite. Nitrite reacts with blood to create methemoglobin. The more methemoglobin in the blood, the worse that blood is at carrying oxygen where it is needed.

What medication converts methemoglobin back to hemoglobin?

The NADH-dependent enzyme methemoglobin reductase (a type of diaphorase) is responsible for converting methemoglobin back to hemoglobin.

Does dapsone cause methemoglobinemia?

Dapsone is a drug that is used in the treatment of leprosy and acne vulgaris owing to its immunosuppressive effects. Long-term administration of dapsone at standard doses (100 mg/day) results in methemoglobinemia in about 15% of patients.

Is methemoglobinemia a genetic disorder?

Autosomal recessive congenital methemoglobinemia is an inherited condition that mainly affects the function of red blood cells.

Can Orajel cause methemoglobinemia?

Benzocaine, a local anesthetic, can cause a condition in which the amount of oxygen carried through the blood is greatly reduced. This condition, called methemoglobinemia, can be life-threatening and result in death.