Primaquine

💊 What is Primaquine used for?

• •The label says primaquine is used for the radical cure of vivax malaria, meaning prevention of relapse (the malaria returning). It is used only for vivax malaria, not for other kinds of malaria.

How it works

The label describes primaquine as a synthetic antimalarial compound. It is meant to clear the malaria parasites that stay hidden in the liver and can cause the infection to come back. The label does not give further detail about how it works in the body.

How it is usually taken

• •The label says primaquine is taken by mouth once a day as part of a course, given at the same time as chloroquine for an active malaria attack. Tablets can be taken with or without food. The label says taking them with food may reduce stomach upset. Follow the exact instructions from your prescriber or pharmacist.

Comes as

• •26.3 mg tablets (equal to 15 mg of primaquine base), round, purple, marked BY4, sold in bottles of 100

⚠️ Primaquine side effects

🛑 Who should not take Primaquine, and who should be careful

The label says not to take it if

• 🚨You are allergic to primaquine, other 8-aminoquinolones, or any ingredient in the tablet.
• 🚨You have severe G6PD deficiency.
• 🚨You are pregnant. The label says primaquine is contraindicated in pregnant women.
• 🚨You are breastfeeding and the infant is found to be G6PD deficient or the infant's G6PD status is unknown.
• 🚨You have recently taken quinacrine, or you are taking it now.

Tell your doctor before taking it if

• •The label says G6PD testing must be done before using primaquine, because people with G6PD deficiency are at risk of hemolytic anemia.
• •Your blood hemoglobin and hematocrit should be checked before treatment, according to the label.
• •Tell your prescriber if you have a personal or family history of hemolytic anemia or favism.
• •Sexually active women who can become pregnant should have a pregnancy test before starting, according to the label.
• •Tell your prescriber about any recent use of quinacrine.
• •The label says people from areas with a high rate of G6PD deficiency (such as Africa, Southern Europe, the Mediterranean region, the Middle East, South-East Asia, and Oceania) may have a higher risk of hemolytic anemia.

🔀 Primaquine with other medicines, food and alcohol

The label says to discuss these with your doctor or pharmacist

• •Quinacrine: The label says using it with primaquine is contraindicated, because toxicity increases.
• •Hemolytic agents and drugs that cause methemoglobinemia: The label says these should be avoided. If they cannot be avoided, close blood monitoring is required.
• •Drugs that prolong the QT interval: The label says close and frequent electrocardiogram (heart rhythm) monitoring is advised if these are used with primaquine.
• •Strong CYP2D6 inhibitors: The label says these may reduce primaquine's antimalarial effect. Alternatives should be considered where possible, and relapse should be monitored more closely if they must be used.
• •MAO-A inhibitors: The label says these may increase primaquine exposure in people with reduced CYP2D6 activity. Starting them may be delayed or alternatives considered until primaquine treatment is finished.
• •CYP1A2 substrates: The label says primaquine can increase levels of drugs such as duloxetine, alosetron, theophylline, and tizanidine. The label's interaction list continues beyond what is shown here, so ask your pharmacist about all your medicines.

Alcohol and food

The label says primaquine can be taken with or without food, and that taking it with food may reduce stomach symptoms. The label does not discuss alcohol.

🤰 Primaquine in pregnancy and breastfeeding

Pregnancy

The label says primaquine is contraindicated in pregnant women. It says the medicine may cause hemolytic anemia in a G6PD-deficient fetus, and that animal data show effects on reproduction and the developing embryo. The label advises that people should avoid pregnancy during treatment, and that sexually active women should have a pregnancy test before starting.

Breastfeeding

The label says breastfeeding is contraindicated when the infant is found to be G6PD deficient or when the infant's G6PD status is unknown.

🗓️ Storage, missed doses and taking too much

Storage

Store at 25°C (77°F), with short excursions permitted between 15°C and 30°C (59°F to 86°F). Keep in a tight, light-resistant container, as the label directs.

If a dose is missed

The label does not say.

If too much is taken

The label lists symptoms of too much primaquine, including abdominal cramps, vomiting, burning stomach distress, headache, trouble sleeping, heart rhythm problems, bluish skin (methemoglobinemia), abnormal blood cell counts, and anemia. Acute hemolysis may be especially severe in people with G6PD deficiency. Treatment is supportive. The label advises contacting a poison center or medical toxicologist for guidance.

🗒️ Questions to ask about Primaquine

• Have I had a G6PD test, and what were the results?
• Do I need a pregnancy test before I start this medicine?
• Which of my other medicines could interact with primaquine?
• What symptoms should make me call you right away?
• Should I take this medicine with food or on an empty stomach?
• How will my blood counts be checked during treatment?

❓ Primaquine: frequently asked questions