G6PD deficiency can cause red blood cells to break down after exposure to certain triggers, including infections, fava beans, some medicines, and chemicals such as mothballs. Warning signs can include dark urine, yellowing of the eyes or skin, unusual paleness, marked tiredness, a fast heartbeat, or shortness of breath. Dark urine with sudden weakness or breathing difficulty needs urgent medical assessment; serious symptoms require emergency care.
What happens during a G6PD-related episode?
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited condition that affects how red blood cells protect themselves from damage. G6PD is an enzyme that helps these cells remain healthy when exposed to certain substances. When the protective effect is reduced, some triggers can cause red blood cells to break down faster than the body can replace them. This process is called hemolysis, and it can lead to a type of anemia called hemolytic anemia.
According to MedlinePlus, many people with G6PD deficiency have no symptoms unless a trigger causes red blood cell damage. An episode may cause changes such as yellowing of the skin or eyes, dark urine, tiredness, or shortness of breath. Some people feel well between episodes. Recognizing possible triggers and seeking care when warning signs appear can help reduce the risk of complications.
Which triggers can cause problems in G6PD deficiency?
Triggers do not affect every person in the same way. The risk depends on factors such as the degree of enzyme deficiency and the substance involved. The most important exposures to know about include certain infections, foods, medicines, and chemicals.
- Infections: Bacterial and viral infections can place stress on red blood cells and trigger hemolysis. Fever or an illness may therefore be relevant even when no new medicine or food has been taken.
- Fava beans: Also called broad beans, these are a recognized food trigger. A reaction associated with eating fava beans is sometimes called favism. People with diagnosed G6PD deficiency are generally advised to avoid them.
- Certain medicines: Some medicines can damage red blood cells in people with G6PD deficiency. Examples include the antimalarial medicine primaquine, certain sulfonamide antibiotics, nitrofurantoin, dapsone, and rasburicase. These examples are not a complete list.
- Chemicals such as naphthalene: Naphthalene, which may be present in mothballs, can trigger red blood cell damage. Keep these products away from children and avoid exposure to their contents.
The Merck Manual Professional Edition identifies infections, certain medicines, and substances such as fava beans and naphthalene among possible triggers. The risk is not the same for every medicine or every person, so a medication's suitability should be checked rather than assumed from its general category.
Which medicines should you check before taking?
Tell every doctor, pharmacist, dentist, and other healthcare professional involved in your care if you have G6PD deficiency. This is particularly important before starting a new prescription medicine, an over-the-counter product, or an herbal or traditional remedy. Share the diagnosis even if you have never experienced symptoms.
Do not assume that every antibiotic, pain reliever, or other medicine is unsafe. Some commonly used medicines can be suitable, while particular medicines or doses may carry a risk. A healthcare professional can check the specific drug and your circumstances. The University College London Hospitals NHS Foundation Trust advises people with G6PD deficiency to tell their healthcare team before taking a new medicine so its safety can be checked.
Do not stop an essential prescribed medicine on your own. If you think a medicine has triggered symptoms, seek urgent medical advice and explain what you took, how much you took, and when you took it. Bring the packaging or a list of your medicines if possible.
What are the warning signs of red blood cell breakdown?
Symptoms can develop when red blood cells are being destroyed faster than the body can replace them. The following are examples of changes that may occur during a hemolytic episode. They are reasons to seek medical assessment, not a checklist for confirming a diagnosis.
- Dark urine: Urine may look brown, tea-colored, or cola-colored rather than its usual color.
- Yellowing of the skin or eyes: The whites of the eyes or the skin may become yellow. This is called jaundice.
- Unusual paleness or marked tiredness: A person may appear paler than usual, feel unusually weak, or have difficulty carrying out normal activities.
- Shortness of breath: Breathing may feel difficult, particularly with activity. More significant anemia can affect how well oxygen is carried around the body.
- A fast heartbeat: The heart may beat faster than usual, or the person may notice a racing or pounding sensation.
- Back or abdominal pain: Some people experience pain in these areas during an episode.
These warning signs are consistent with the symptoms described by the Cleveland Clinic. Dark urine, yellowing of the eyes or skin, and unusual weakness deserve prompt attention, especially following an infection or a possible exposure to a trigger.
When should you seek emergency care?
Get emergency medical help immediately if you or someone in your care develops difficulty breathing, collapses or faints, becomes confused or difficult to wake, or experiences rapidly worsening weakness or other serious symptoms. These changes may indicate a significant medical problem and should not wait for a routine appointment.
Seek urgent, same-day medical assessment if you notice new brown or cola-colored urine, yellowing of the skin or eyes, marked paleness, a racing heartbeat, unusual exhaustion, or back or abdominal pain after a possible trigger. A clinician can assess whether red blood cell breakdown or another condition is responsible and decide whether blood tests or treatment are needed.
If a child with known or suspected G6PD deficiency develops these signs, contact a healthcare professional promptly. Do not wait for several symptoms to appear together. If the child has severe symptoms or is becoming rapidly more unwell, seek emergency care.
Why is jaundice especially important in newborns?
Newborns with G6PD deficiency can develop jaundice during the first days of life, sometimes without an obvious exposure to a medicine or food. Yellowing occurs when bilirubin, a substance produced during the breakdown of red blood cells, builds up in the body. Jaundice has several possible causes, so its appearance alone does not establish that a baby has G6PD deficiency.
Any suspected jaundice in a newborn needs prompt medical assessment, particularly when G6PD deficiency is known or suspected. Seek emergency care if a jaundiced baby is unusually sleepy or difficult to wake, is not feeding, becomes floppy, or has breathing difficulties. The NHS guidance on jaundice in babies identifies these changes as warning signs requiring immediate attention. Prompt assessment allows the care team to measure bilirubin and arrange treatment when necessary.
What should you do after a possible trigger exposure?
If you think you have been exposed to a trigger, note the substance or medicine involved and the time of exposure. If symptoms develop, explain the possible exposure to the healthcare professional rather than waiting to see whether the symptoms disappear. If a child has swallowed a mothball or another potentially harmful chemical, seek immediate advice from local emergency services or a poison information service, even if the child initially appears well.
For severe or rapidly developing symptoms, do not delay emergency care while gathering product details. Take medicine packaging, a photograph of the label, or a current medication list only if doing so will not delay getting help.
How can you reduce the risk of another episode?
Practical steps can make exposure to known triggers less likely:
- Tell healthcare professionals about G6PD deficiency before receiving a new prescription or taking a new nonprescription, herbal, or traditional product.
- Avoid fava beans and substances known to trigger hemolysis for you, following the guidance given by your healthcare professional.
- Keep naphthalene-containing mothballs and other hazardous chemicals away from children and avoid unnecessary exposure.
- Seek timely medical advice for infections, especially if they cause fever or leave you feeling increasingly unwell.
- Keep a written list of your condition and medicines, or carry a medical alert card, so other healthcare professionals can check your risks during urgent treatment.
These precautions do not mean that every exposure will cause a reaction. They help you and your healthcare team identify avoidable risks while ensuring that necessary medicines and treatment are not delayed without good reason.