Hydroxychloroquine (Plaquenil) and chloroquine
Long-term medicines for lupus and rheumatoid arthritis, and for malaria. Their US labels warn that red blood cells can break down in people with G6PD deficiency.
What this drug connects to
The genes involved
Hydroxychloroquine (Plaquenil), taken for years for lupus and rheumatoid arthritis, and chloroquine for malaria both carry a G6PD warning in their US labels. The Plaquenil label says haemolysis has been reported in people with G6PD deficiency and asks for watching for it, especially alongside other medicines that can cause it. It is a reason to watch, not a reason the medicine cannot be used.
US prescribing information for PLAQUENIL (hydroxychloroquine sulfate), revised October 2024, section 5.7; the FDA Table of Pharmacogenomic Biomarkers lists the same G6PD row for chloroquine. A label warning, not the CPIC guideline.
Questions about Hydroxychloroquine (Plaquenil) and chloroquine
What are hydroxychloroquine and chloroquine?
They are old medicines first made for malaria. Hydroxychloroquine, sold as Plaquenil, is now mostly taken for years at a time for lupus and rheumatoid arthritis. Chloroquine is still used for malaria.
What does G6PD deficiency have to do with them?
G6PD is an enzyme that protects red blood cells from damage. People born with too little of it, G6PD deficiency, can have red cells that break apart, called haemolysis. The Plaquenil label says haemolysis has been reported in people with G6PD deficiency, and to watch for it, especially alongside other medicines that can cause it.
Does G6PD deficiency mean I cannot take hydroxychloroquine?
No. The label asks for watchfulness, not for avoiding it. If you know you have G6PD deficiency, tell your doctor before starting, and report dark urine, yellowing skin or eyes, unusual tiredness or breathlessness.
Who is more likely to have G6PD deficiency?
It is passed down on the X chromosome, so it shows up more in men, and it is common in people whose families come from Africa, the Mediterranean, the Middle East and South and Southeast Asia. The G6PD deficiency page on this site has the details.
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Hydroxychloroquine (Plaquenil) and chloroquine. MyGeneLog™. https://www.mygenelog.com/drugs/hydroxychloroquine-chloroquine