Medical Editor: John P. Cunha, DO, FACOEP
Halfan (halofantrine hydrochloride) is an antimalarial drug indicated for the treatment of adults who can tolerate oral medication and who have mild to moderate malaria (equal to or less than 100,000 parasites/mm3) caused by Plasmodium falciparum or Plasmodium vivax. Common side effects of Halfan include:,
Patients with no previous exposure or minimal exposure to malaria should be considered “non-immune” and should receive 500 mg (2 x 250 mg tablets) of Halfan every 6 hours for three doses (total first course dosage 1500 mg). This course of therapy should be repeated 7 days after the first course. Halfan may interact with ketoconazole or drugs known to prolong the QTc interval such as mefloquine. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant before using Halfan; it is unknown how it would affect a fetus. It is unknown if Halfan passes into breast milk. Because of the potential for serious adverse reactions in nursing infants, breastfeeding is not recommended while using Halfan.
Our Halfan (halofantrine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
The following adverse events were reported in normal subjects given Halfan 1000 mg to 1500 mg in a single dosing course.
Gastrointestinal: Abdominal pain (10%), anorexia (5%), diarrhea (5%), nausea (10%), vomiting (10%).
Central Nervous System: Dizziness (5%), headache (5%).
In clinical trials involving 933 patients treated with three 500 mg doses (500 mg every 6 hours), the following clinical adverse events were reported.
There were no deaths or permanent disabilities thought related to drug toxicity. Five patients discontinued medication due to adverse events. Three patients vomited medicine repeatedly.
Though temporally related to drug administration, the relationship of the following serious adverse events to malaria or underlying illness as opposed to drug toxicity could not be established. Two patients had decreased consciousness; other serious adverse events reported during clinical trials included convulsions (3 cases), stomatitis (3 cases), moderately severe diarrhea (2 cases), pulmonary edema (1 case), tetany (1 case), hypertensive crisis (1 case), cerebrovascular accident (1 case).
The most frequently reported adverse events thought possibly- or probably-related to halofantrine were: abdominal pain (8.5%), diarrhea (6.0%), dizziness (4.5%), vomiting (4.3%), nausea (3.4%), cough (3.0%), headache (3.0%), pruritus (2.6%), rigors (1.7%) and myalgias (1.3%). These events are also characteristic of malaria.
Pruritus was reported in a higher proportion of highly pigmented patients than in other patients.
Adverse events thought possibly- or probably-related to halofantrine affecting <1% of patients studied in the clinical trials included:
Body as a Whole: Fatigue, malaise.
Cardiovascular: Chest pain, palpitations, postural hypotension.
Gastrointestinal: Abdominal distention, anorexia, constipation, dyspepsia.
Mucous Membrane: Stomatitis.
Musculoskeletal: Arthralgia, back pain.
Central Nervous System: Asthenia, confusion, convulsions, depression, paresthesia, sleep disorder.
Renal: Urinary frequency.
Special Senses: Abnormal vision, tinnitus.
The most frequently noted laboratory abnormalities that occurred following drug administration in the clinical trials were decreased hematocrit, elevated hepatic transaminases, decreased and increased white blood cell counts, and decreased platelet counts. These alterations returned to normal limits within 2 to 3 weeks post-infection. The causal relationship of these changes to Halfan is unclear, as these laboratory abnormalities can also occur with acute malaria.
Halofantrine was marketed in Europe starting in 1988. The following additional adverse experiences have been reported in postmarketing surveillance outside the United States: Facial edema and urticaria (allergic/anaphylactic reactions) in rare cases.
Hemolysis/hemolytic anemia (including immune hemolytic anemia) which may compromise renal function have been reported in patients with malaria who have been treated with halofantrine. Hemolytic reactions may also be observed in patients with malaria in the absence of halofantrine.
Prolongation of QT interval has been reported. There have been rare reports of serious ventricular dysrhythmias sometimes associated with death. These cases have occurred particularly under certain conditions which include uses of doses higher than recommended, recent or concomitant treatment with mefloquine, or presence of preexisting prolongation of QT interval.1
Read the entire FDA prescribing information for Halfan (Halofantrine Hydrochloride Tablets)