How methemoglobin is formed?
Methemoglobin (MetHb) is formed by the reversible oxidation of heme iron to the ferric state (Fe3+). Normally, a small amount of methemoglobin is continuously formed by oxidation of iron during normal oxygenation and deoxygenation of hemoglobin.
What happens to the tissues when methemoglobin is produced?
Methemoglobin results from the presence of iron in the ferric form instead of the usual ferrous form. This results in a decreased availability of oxygen to the tissues. Symptoms are proportional to the methemoglobin level and include skin color changes and blood color changes at levels up to 15% (see the image below).
Which antimalarial drug belongs to 8 Aminoquinoline derivatives?
primaquine
The antimalarial drug primaquine, an 8-aminoquinoline derivative, is one example of such a drug.
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 does hemoglobin turn to methemoglobin?
Methemoglobin forms when hemoglobin is oxidized to contain iron in the ferric [Fe3+] rather than the normal ferrous [Fe2+] state. Any of the four iron species within a hemoglobin molecule that are in the ferric form are unable to bind oxygen.
What means methemoglobin?
Methemoglobin is a form of hemoglobin that cannot carry oxygen. In methemoglobinemia, tissues cannot get enough oxygen. Symptoms may include headache, dizziness, fatigue, shortness of breath, nausea, vomiting, rapid heartbeat, loss of muscle coordination, and blue-colored skin.
What causes low methemoglobin?
Congenital methemoglobinemia is caused by a genetic defect that you inherit from your parents. This genetic defect leads to a deficiency of a certain enzyme, or protein. This protein is responsible for converting methemoglobin to hemoglobin.
Is chloroquine a 4-Aminoquinoline?
Chloroquine (CQ) is a safe and economical 4-aminoquinoline (AQ) antimalarial. However, its value has been severely compromised by the increasing prevalence of CQ resistance. This study examined 108 AQs, including 68 newly synthesized compounds.
How does nitric oxide cause methemoglobinemia?
Nitric oxide oxidizes heme iron to the ferric state, resulting in the formation of methemoglobin. [2] Methemoglobin has higher oxygen affinity and decreased oxygen-carrying capacity of the blood due to fewer hemes to bind oxygen.
How is methemoglobin different from hemoglobin?
The only difference between hemoglobin and methemoglobin is that one or more of the four iron atoms in the methemoglobin molecule are in the ferric (Fe3+) rather than the ferrous (Fe2+) state and are therefore incapable of binding oxygen [3].