Primaquine

Introduction

Written by Kirstyn Hill, PharmD, MPH
Medically reviewed by Victor Nguyen, PharmD, MBA
Updated on October 19, 2023

Primaquine (PRIM a kwin) is a generic medication prescribed for the treatment and prevention of malaria. Primaquine belongs to a group of drugs called antimalarial agents.

Side effects of primaquine

Primaquine may cause mild or serious side effects. More common mild side effects of primaquine and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about primaquine’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for primaquine listed in the “Resources” section.

Mild side effects

More common mild side effects reported with primaquine are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about primaquine’s side effects based on the form, refer to the prescribing information for primaquine listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Primaquine oral tablet’s mild side effects include:

• nausea and vomiting
• abdominal cramps
• dizziness
• rash
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for primaquine” section.

Serious side effects

Serious side effects of primaquine are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about primaquine’s side effects based on the form, refer to the prescribing information for primaquine listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, primaquine’s serious side effects include: 

• low white blood cell count
• low red blood cell count
• atypical heart rate
• long QT syndrome
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for primaquine” section.

Common questions about primaquine

Below you’ll find answers to a few commonly asked questions about primaquine.

What brand names are available for primaquine?

Primaquine is not available as a brand-name product in the United States.

A generic medication is an identical copy of the active drug in a brand-name medication. (An active drug is the ingredient that makes a medication work.) Generic drugs are believed to be as effective and safe as brand-name drugs. And generic drugs typically cost less compared with brand-name drugs.

How does primaquine work? And how long does it take to start working?

Primaquine’s mechanism of action (how a drug works) is by causing damage to and the removal of the parasite known to cause malaria. The parasite, called Plasmodium vivax, is one of four different species that can cause malaria in humans. Doctors may prescribe primaquine to treat other species of malarial parasites as well.

Primaquine begins working 1–3 hours after taking it. It is important to continue taking primaquine as your doctor prescribes, to ensure the infection is cleared.

If you’d like to know more about how primaquine works, talk with your doctor or pharmacist.

Interactions and warnings for primaquine

Below, you’ll find information about primaquine’s possible interactions and warnings.

Interactions of primaquine

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take primaquine, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs 
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for primaquine” section below.

Warnings for primaquine

Some people should not take primaquine, and others should take it cautiously.

Primaquine could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether primaquine is a safe option for you.

Ask your doctor about specific warnings for primaquine, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Primaquine can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to primaquine or any of its ingredients, your doctor will likely not prescribe primaquine. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to primaquine, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of primaquine

If you take primaquine by mouth, you should not take more primaquine than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much primaquine, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and primaquine

Information about primaquine and pregnancy and breastfeeding is described below.

Primaquine and pregnancy

Primaquine should not be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. Your doctor may suggest birth control options to use during treatment with primaquine.

Primaquine and breastfeeding

It’s not known whether primaquine should be taken while breastfeeding. If you’re breastfeeding or planning to do so, talk with your doctor before taking this medication.

Uses of primaquine

The Food and Drug Administration (FDA) approves prescription drugs such as primaquine for certain conditions. The approved use for primaquine is described below.

Use for malaria

Doctors may prescribe primaquine oral tablet for treating and helping to prevent malaria. It’s used for this purpose in adults. It’s usually prescribed as a short-term treatment.

Malaria is a life threatening disease caused by infected mosquitoes. When an infected mosquito bites a human, it passes a parasite into that person’s blood. Within 3 days, the parasite begins to grow and continues to infect other red blood cells.

Symptoms of malaria include:

• fever and flu-like symptoms
• chills
• nausea, vomiting, and diarrhea
• kidney failure
• seizures
• confusion
• coma

Primaquine may be prescribed together with other medications for the treatment and prevention of malaria.

Doctors may not prescribe primaquine oral tablet in certain situations, such as in pregnant people and those with a history of severe G6PD deficiency (a genetic condition).

What to ask your doctor

Let your doctor know if you have questions about primaquine or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Does primaquine have long-term side effects?
• How long do I need to take primaquine?
• What happens if I miss a dose of primaquine?

Resources

• Daher A, et al. (2022). Pharmacokinetics of chloroquine and primaquine in healthy volunteers. https://malariajournal.biomedcentral.com/articles/10.1186/s12936-021-04035-z
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm 
• Primaquine phosphate tablet, film coated. (2018). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/09531382-2e06-4164-a7e1-169a1488788a/spl-doc#ID-4
• United States Centers for Disease Control and Prevention. (2023). Treatment of malaria: Guidelines for clinicians. https://www.cdc.gov/malaria/diagnosis_treatment/clinicians1.html%C2%A0

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.