From the FDA Drug Label
In patients with G6PD deficiency who experience metoclopramide-induced methemoglobinemia, methylene blue treatment is not recommended
- Metoclopramide may not be safe in patients with G6PD deficiency due to the risk of methemoglobinemia.
- The FDA drug label warns against the use of methylene blue to treat methemoglobinemia in patients with G6PD deficiency who are taking metoclopramide 1 2.
From the Research
Maxalon (metoclopramide) is generally considered safe for patients with G6PD deficiency. Unlike certain medications that can trigger hemolytic anemia in G6PD-deficient individuals, metoclopramide is not known to cause oxidative stress to red blood cells or precipitate hemolysis in these patients. Metoclopramide works as an antiemetic and prokinetic agent by blocking dopamine receptors and enhancing acetylcholine release in the gastrointestinal tract, mechanisms that do not interfere with the pentose phosphate pathway affected in G6PD deficiency.
Key Points to Consider
- When prescribing Maxalon, the standard adult dosage is typically 10 mg three to four times daily, with adjustments needed for renal impairment.
- Common side effects include drowsiness and extrapyramidal symptoms, particularly with prolonged use.
- A study from 3 showed that metoclopramide hydrochloride had no inhibition effects on G6PD enzyme activity.
- While metoclopramide is considered safe regarding G6PD status, it's always prudent to monitor any patient starting a new medication for unexpected reactions, especially those with underlying medical conditions.
- The risk of tardive dyskinesia due to metoclopramide is low, in the range of 0.1% per 1000 patient years, as reported in a study from 4.
Important Considerations for G6PD Deficiency
- G6PD deficiency affects about 400 million people worldwide, and most individuals with G6PD deficiency are asymptomatic throughout life, as stated in a review from 5.
- Symptoms of acute hemolysis associated with G6PD deficiency include anemia, fatigue, back or abdominal pain, jaundice, and hemoglobinuria.
- The most common precipitators of oxidative stress and hemolysis in G6PD deficiency include medication use and infection.