Nifurtimox Side Effects

Medically reviewed by Drugs.com. Last updated on Mar 15, 2025.

Applies to nifurtimox: oral tablet.

Precautions

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood tests may be 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, you must have a negative pregnancy test before you will be allowed to receive this medicine. Female patients should use an effective form of birth control during treatment and for at least 6 months after the last dose. Male patients who have female partners should use an effective form of birth control (eg, condom) during treatment 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.

This medicine may cause vomiting, rash, decreased appetite, fever, and irritability in infants exposed to breast milk. Talk with your doctor if you have any concerns about this.

If you plan to have children, talk with your doctor before using this medicine. Some men using this medicine have become infertile (unable to have children).

Serious allergic reactions can occur with this medicine. Check with your doctor right away if you have blurred vision, confusion, dizziness, fast or slow heartbeat, faintness, or lightheadedness when getting up from a lying or sitting position suddenly, itching skin, skin rash, sweating, swelling of the arms, face, legs, lips, tongue, or throat, trouble breathing, unusual tiredness or weakness with this medicine.

Do not drink alcohol during treatment with this medicine.

This medicine may cause nausea and vomiting which can lead to decreased appetite and weight. Check you body weight every 14 days. Your doctor may change your dose if needed.

Nifurtimox may increase your risk for acute attacks of porphyria. Call your doctor right away if you have darkening of the urine, fluid-filled skin blisters, itching of the skin, light-colored stools, skin sensitivity to the sun, skin thinness, or yellow eyes or skin.

This medicine may cause muscle weakness or tremors. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Serious side effects of nifurtimox

Along with its needed effects, nifurtimox may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking nifurtimox:

More common side effects

• decreased appetite
• diarrhea
• dizziness
• fever
• headache
• nausea
• stomach pain
• vomiting
• weight loss

Less common side effects

• black, tarry stools
• chest pain
• chills
• cough
• painful or difficult urination
• pale skin
• sores, ulcers, or white spots on the lips or in the mouth
• sore throat
• swollen glands
• trouble breathing
• unusual bleeding or bruising
• unusual tiredness or weakness

Rare side effects

• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• difficulty in moving
• fainting
• fear, nervousness
• feeling of constant movement of self or surroundings
• irritability
• joint pain
• lack or loss of strength
• lower back or side pain
• muscle aching or cramping
• muscle pains or stiffness
• seizure
• sensation of spinning
• shakiness in the legs, arms, hands, feet
• swollen joints
• trembling or shaking of the hands or feet

Incidence not known

• agitation
• anxiety
• bleeding gums
• blood in urine or stools
• delusions
• difficulty swallowing
• dry mouth
• fast or slow heartbeat
• hallucinations
• itching, skin rash
• lack of feeling or emotion
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs
• loss of memory
• numbness, tingling, pain, or weakness in the hands or feet
• pinpoint red spots on skin
• problems with memory
• puffiness or swelling of the eyelids or around the eyes, face, lips or tongue
• restlessness
• shaking
• tightness in the chest
• trouble sleeping

Other side effects of nifurtimox

Some side effects of nifurtimox may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Rare side effects

• Sleepiness or unusual drowsiness

For healthcare professionals

Applies to nifurtimox: oral tablet.

General adverse events

The side effects reported most often in patients treated with this drug for 60 days were vomiting, abdominal pain, headache, decreased appetite, nausea, pyrexia, and rash.^[Ref]

Gastrointestinal

• Very common (10% or more): Vomiting (14.6%), abdominal pain (included abdominal pain, upper abdominal pain; 13.2%)
• Common (1% to 10%): Nausea, diarrhea^[Ref]

Nervous system

• Very common (10% or more): Headache (12.8%)
• Common (1% to 10%): Dizziness
• Uncommon (0.1% to 1%): Vertigo, paresthesia, tremor, somnolence, seizure, syncope
• Postmarketing reports: Vertigo, amnesia, polyneuropathy^[Ref]

Metabolic

• Very common (10% or more): Decreased appetite (10.5%)^[Ref]

Other

• Common (1% to 10%): Pyrexia, weight decreased
• Uncommon (0.1% to 1%): Asthenia, fatigue^[Ref]

Dermatologic

• Common (1% to 10%): Rash (included rash, macular rash, maculopapular rash, morbilliform rash, papular rash), urticaria
• Uncommon (0.1% to 1%): Pruritus
• Postmarketing reports: Angioedema, drug reaction with eosinophilia and systemic symptoms (DRESS)^[Ref]

Hematologic

• Common (1% to 10%): Anemia, eosinophilia
• Uncommon (0.1% to 1%): Neutropenia, leukopenia
• Postmarketing reports: Thrombocytopenia^[Ref]

Psychiatric

• Uncommon (0.1% to 1%): Irritability, anxiety
• Postmarketing reports: Apathy, agitation, psychotic behavior, sleep disorder^[Ref]

Musculoskeletal

• Uncommon (0.1% to 1%): Arthralgia, myalgia
• Postmarketing reports: Muscle weakness^[Ref]

Hypersensitivity

• Postmarketing reports: Hypersensitivity reactions (including anaphylaxis)^[Ref]

See also:

Further information

Nifurtimox side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer