Krintafel (Tafenoquine) - Oral

Warning:

What Is Krintafel?

Krintafel (tafenoquine) is a pill taken by mouth to treat and prevent the relapse of Plasmodium vivax malaria, which is an infection caused by parasites that mosquitoes carry. Plasmodium vivax is the name of the parasite that almost always causes malaria.

After acute malaria infections, this parasite can lie dormant (inactive and not causing symptoms) in your liver, then cause later relapses of malaria. This means you can experience more malaria episodes without being bitten again by a mosquito. Krintafel prevents these relapses.

Krintafel works against the parasite within your liver by disturbing certain processes required to grow. It is an add-on medication and must be taken with another antimalarial drug called chloroquine.

The generic name for Krintafel is tafenoquine, but it is only available as a brand name product. It’s also a prescription drug, so you can’t purchase it over-the-counter (OTC). You will need a prescription from a healthcare provider.

Drug Facts

Generic Name: Tafenoquine

Brand Name: Krintafel

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Antimalarial

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Tafenoquine

Dosage Form: Tablet

What Is Krintafel Used For?

Krintafel is used in people aged 16 or older in addition to another antimalarial drug to treat and prevent the malaria relapse, a parasitic infection most often transmitted by mosquitoes.

The disease is rare in the United States (U.S.), but unfortunately much more common in other areas of the world. Most cases in the U.S. come from travelers who have visited tropical areas like Africa, South and Southeast Asia, and parts of South and Central America and the Caribbean.

The "classic" sign of infection is malaria paroxysm, the cycling of cold symptoms (chills and shivering) with hot symptoms (sweating and fever) every few hours.

Some of the most common early symptoms of malaria include:

  • Headache
  • Fever
  • Fatigue
  • Dry cough
  • Nausea
  • Vomiting

More severe cases of malaria can cause:

  • Acute breathing problems
  • Changes in consciousness
  • Jaundice (yellowing of the skin and eyes)
  • Shock
  • Coma
Krintafel (Tafenoquine) Drug Information: A person with their heart

Verywell / Zoe Hansen

How to Take Krintafel

Take Krintafel exactly as your healthcare provider tells you to. You will take this medication along with another antimalarial drug, chloroquine.

You will most likely take Krintafel as a single dose on the first or second day you start taking chloroquine. Swallow the tablets whole. Do not break, crush, or chew them.

Take Krintafel with food to increase how much of the drug gets absorbed into your system. Ideally, this would be with a meal that includes plenty of fat. Studies showed higher absorption rates in people who ate around 1,000 calories, at least 60% of them from fat. This may sound like a burden, but remember, Krintafel is usually just taken once as a single dose.

If you vomit within one hour after taking your dose of Krintafel, you should repeat the dose. If the same thing happens again, don’t attempt another dose. Consult your healthcare provider.

Storing Krintafel

Store Krintafel at room temperature (between 68 F and 77 F) in the original package, out of reach of children and pets. Avoid storing it in an area with a lot of heat and moisture, like the bathroom.

How Long Does Krintafel Take to Work?

Krintafel remains in your system for quite a long time–at 16 days, half of it remains in your system. It works during these couple weeks with another antimalarial to treat the infection and fight relapse (the return of the infection).

What Are the Side Effects of Krintafel?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

The following are some of the more common side effects of using Krintafel. If you notice these side effects and think they are severe or if they do not go away, you should notify your healthcare provider:

  • Dizziness
  • Nausea
  • Vomiting
  • Decreased hemoglobin (a protein in your red blood cells that delivers oxygen to your organs)
  • Headache

Severe Side Effects

Call your healthcare provider immediately if you feel you are experiencing severe side effects such as any of the following. Call 911 if your symptoms feel life-threatening or think you’re having a medical emergency.

Severe side effects and their symptoms include:

  • Methemoglobinemia is rare but has been associated with taking Krintafel. It is a blood disorder that makes some of your red blood cells unable to carry oxygen, resulting in symptoms like cyanosis, weakness, shortness of breath, heart rhythm problems, or impaired thinking in severe cases.
  • Psychiatric symptoms such as anxiety, insomnia, or abnormal dreams may occur, potentially more so in individuals with a history of psychiatric problems.
  • Hypersensitivity reactions such as urticaria and angioedema (hives and swelling) are possible when taking Krintafel. Be aware of signs and symptoms, including dizziness, rash, upset stomach, or patchy welts on your skin. Seek help as soon as possible if you experience these symptoms.

Long-Term Side Effects

No specific long-term side effects apart from the possible ones listed above are of concern, as Krintafel is typically taken once as a single dose.

Report Side Effects

Krintafel may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Krintafel Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For preventing malaria:
      • Adults:
        • Before your trip (loading dose)—Two 100 milligrams (mg) tablets taken together once daily for 3 days.
        • While you are in the malaria area (maintenance dose)—Two 100 milligrams (mg) tablets taken together once a week, 7 days after the last loading dose.
        • After your trip—Two 100 milligrams (mg) tablets taken together, 7 days after the last maintenance dose.
      • Children—Use and dose must be determined by your doctor.
    • For preventing malaria relapse:
      • Adults and children 16 years of age and older—300 milligrams (mg) taken as a single dose (two 150-mg tablets taken together). This medicine must be taken on the first or second day of your malaria treatment (eg, chloroquine).
      • Children younger than 16 years of age—Use and dose must be determined by your doctor.

Modifications

In some cases, you may need to adjust your treatment with Krintafel or use an alternative medication.

History of Psychiatric Disorders

Having any kind of psychiatric history doesn’t automatically rule out Krintafel as a treatment option, but you should have a conversation with your healthcare provider about the benefit of taking it given the potential risk for adverse psychiatric reactions. Note that these reactions could be delayed in onset given the fact that Krintafel remains in your system for several weeks.

Pregnancy

Taking Krintafel while pregnant is not recommended. The effect the drug has on the fetus is not well understood and may be harmful. This is especially true if the fetus has G6PD deficiency, a genetic enzyme deficiency that may cause serious blood problems if exposed to certain medications such as Krintafel.

Nursing

If your infant has G6PD deficiency, or if you don’t know the G6PD status of your baby, don’t breastfeed for three months after you take Krintafel.

Children

The safety and effectiveness of Krintafel has not been established in children younger than 16. Therefore, this medication is not approved for use in this population.

Older Age

Studies specifically evaluating Krintafel use in people older than 65 have not been done, but clinical experience hasn’t suggested that older individuals respond differently to Krintafel compared with younger adults. No dosage changes are necessary.

Missed Dose

Krintafel is taken one time as a single dose, so there’s no need to worry about missing any doses. Your healthcare provider will let you know when to take your Krintafel dose in relation to your other antimalarial medication.

Overdose: What Happens If I Take Too Much Krintafel?

Since Krintafel is taken just one time as a single dose, you don’t need to be concerned about overdosing.

If for some reason, you do end up with too much Krintafel in your system, symptoms may include low hemoglobin levels and potentially methemoglobinemia, in which case you should notify your healthcare provider as soon as possible.

What Happens If I Overdose on Krintafel?

If you think you or someone else may have overdosed on Krintafel, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or experiences signs of an overdose after taking Krintafel, call 911 immediately.

Precautions

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It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood and urine tests are needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting treatment. Use an effective form of birth control to keep from getting pregnant during treatment with this medicine and for at least 3 months after the last dose. If you think you have become pregnant while using this medicine, tell your doctor right away.

Before taking this medicine, you and your child should be tested for G6PD deficiency or favism (blood disorder). Tafenoquine may cause hemolytic anemia in patients with these conditions. Talk to your doctor if you have concerns about this.

This medicine may cause some people to be agitated, irritable, or display other abnormal behaviors. Make sure the doctor knows if you have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. Also tell the doctor if you have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared. If you or your caregiver notice any of these side effects, tell your doctor right away.

This medicine may cause a serious allergic reaction, including angioedema, which can be life-threatening and requires immediate medical attention. Tell your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals.

Malaria is spread by the bites of certain kinds of infected female mosquitoes. If you are living in or will be traveling to an area where there is a chance of getting malaria, the following mosquito-control measures will help to prevent infection:

  • If possible, avoid going out between dusk and dawn because it is at these times that mosquitoes most commonly bite.
  • Remain in air-conditioned or well-screened rooms to reduce contact with mosquitoes.
  • Wear long-sleeved shirts or blouses and long trousers to protect your arms and legs, especially from dusk through dawn when mosquitoes are out.
  • Apply insect repellant, preferably one containing DEET, to uncovered areas of the skin from dusk through dawn when mosquitoes are out.
  • If possible, sleep in a screened or air-conditioned room or under mosquito netting, preferably coated or soaked with pyrethrum, to avoid being bitten by malaria-carrying mosquitoes.
  • Use mosquito coils or sprays to kill mosquitoes in living and sleeping quarters during evening and nighttime hours.

Do not use Krintafel™ with medicines to treat malaria other than chloroquine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn't Take Krintafel?

You shouldn’t take Krintafel if any of the following apply to you:

  • G6PD deficiency: You should let your healthcare provider know before using Krintafel if you have a genetic disorder called G6PD deficiency. If you don’t know whether you have this deficiency, your healthcare provider should test you before prescribing Krintafel. Using Krintafel with this disorder can cause dangerous changes in red blood cell counts (anemia) as well as clotting and bleeding problems.
  • A history of severe psychiatric disorders: Have a conversation with your healthcare provider about whether you should take Krintafel.
  • If you are pregnant: Taking Krintafel while pregnant isn’t recommended since the effect the drug has on the fetus isn’t well understood and may be harmful, especially if the fetus has G6PD deficiency.

What Other Medications Interact With Krintafel?

Taking Krintafel with certain drugs that are metabolized by the proteins organic cation transporter-2 (OCT2) and multidrug and toxin extrusion (MATE) may increase the concentrations of those drugs in your body, potentially making the effects of those drugs stronger.

A few examples of OCT2 substrates include:

And some MATE substrates:

Additionally, taking Krintafel with antimalarials other than chloroquine can increase the risk of P. vivax malaria recurrence.

Ensure the healthcare provider prescribing Krintafel for you is aware of your complete medication list. They may have you take a break from some of these medications or temporarily decrease the dose of them while Krintafel is in your system.

What Medications Are Similar to Krintafel?

Krintafel is used to target the dormant form of the malaria parasite, to prevent relapses of the infection. It is taken in addition to other antimalarial drugs that target the active form of the malaria parasite. Some examples of other antimalarial drugs are:

  • Arakoda, which is the same drug as Krintafel, but taken to prevent (prophylaxis) malaria
  • Chloroquine
  • Plaquenil (hydroxychloroquine)
  • Qualaquin (quinine)
  • Primaquine
  • Mefloquine
  • Malarone (atovaquone/proguanil)

You may take one or some of these drugs along with Krintafel. Ask your healthcare provider if you have questions.

Frequently Asked Questions

  • What is Krintafel used for?

    Krintafel is an oral medication taken as a single dose to treat malaria. Its purpose is to prevent infection relapses caused by a dormant parasite. Krintafel is taken in addition to another antimalarial drug.

  • How does Krintafel work?

    Krintafel targets the dormant parasite that can live in the livers of individuals that get infected with malaria. This dormant parasite can remain inactive for periods of time, then get reactivated (without the individual getting bitten by a transmitting mosquito) to cause symptoms of infection again. Krintafel targets the inactive parasite by interfering with the processes that it requires to grow.

  • What are the side effects of Krintafel?

    The most common side effects of Krintafel include nausea, vomiting, dizziness, headache, and a lowered hemoglobin level. More severe potential side effects include methemoglobinemia and psychiatric effects such as anxiety, strange dreams, or insomnia.

  • What are reasons I shouldn't take Krintafel?

    You should not take Krintafel if you’re pregnant, if you have a history of serious psychiatric disorders, or if you have a genetic enzyme deficiency called G6PD deficiency. Using Krintafel with this disorder can cause dangerous changes in red blood cell counts (anemia) as well as clotting and bleeding problems.

How Can I Stay Healthy While Taking Krintafel?

Malaria is rare in the United States. Only a couple thousand infections are diagnosed per year, and the vast majority is in travelers returning from tropical areas where transmission is high. If you are planning to travel to a tropical area where exposure to malaria is possible or likely, it is essential to take proper precautions like packing and using plenty of insect repellant, taking prophylactic medications, and potentially receiving a vaccine.

You can use the CDC Yellow Book to see recommendations for the country or countries you’ll be visiting, and even see where there is the highest risk of malaria. Speak with your healthcare provider to get everything you need before you leave.

If you feel you have symptoms of an infection and you have recently traveled, do not ignore the signs. Promptly see a healthcare provider. When left untreated, malaria can progress to much more severe infections. Treatment should be initiated as soon as possible, and adherence to your medications is essential. Treatment with the right drugs against the right parasite can clear the infection from your body.

In addition to treating malaria with prescription drugs, you can support good health by making sure you are staying hydrated, maintaining adequate nutrition with a proper diet, getting enough rest, and staying at comfortable temperatures. You can also use over-the-counter pain and fever medications if approved and directed by your healthcare provider.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Krintafel (tafenoquine) prescribing information.

  2. Lacerda MVG, Llanos-Cuentas A, Krudsood S, et al. Single-dose tafenoquine to prevent relapse of Plasmodium vivax malaria. N Engl J Med. 2019;380:215-228. doi:10.1056/NEJMoa1710775

  3. Centers for Disease Control and Prevention. About malaria.

  4. Duparc S, Chalon S, Miller S. Neurological and psychiatric safety of tafenoquine in Plasmodium vivax relapse prevention: a review. Malaria Journal. 2020. doi:10.1186/s12936-020-03184-x

  5. DrugBank Online. OCT2 Substrates.

  6. DrugBank Online. MATE Substrates.

By Sara Hoffman, PharmD
Sara is a clinical pharmacist that believes everyone should understand their medications, and aims to achieve this through her writing.