Halfan Side Effects

Please note - some side effects for Halfan may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Halfan - for the Consumer

Halfan

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Halfan:

Cough; diarrhea; dizziness; headache; loss of appetite; nausea; stomach pain; vomiting.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormal skin sensations; chest pain; dark urine; fast heartbeat; fatigue; pale color; seizures; shortness of breath; vision changes.

Side Effects by Body System

Cardiovascular

Higher risk may be associated with larger than recommended doses, previous or concurrent mefloquine treatment, preexisting QT interval prolongation, or concurrent administration of other QT interval-prolonging drugs. Prolonged QTc interval has been reported in up to 81% of adults treated with standard halofantrine doses and in 100% of patients treated with high doses (72 mg/kg). Prolonged QTc interval has been reported in 50% of children and prolonged PR interval has been reported in 38% of children (n=21). Females may have a higher risk of adverse cardiovascular effects.

It has been proposed that halofantrine prolongs repolarization by blocking HERG potassium channels.

Cardiovascular side effects have included QT interval prolongation, torsades de pointes, ventricular arrhythmias, and death. Chest pain and palpitations have been reported less than 1% of patients in clinical trials, and orthostatic hypotension has been reported in less than 1% to 33% of patients. Hypertensive crisis (1/933) and cerebrovascular accident (1/933) have been reported, although causality was not clearly established. Quinidine-like electrocardiographic changes have also been reported.

Gastrointestinal

Gastrointestinal (GI) side effects have included abdominal pain (8.5%), diarrhea (6%), vomiting (4.3%), and nausea (3.4%), although these symptoms may also occur with a malarial infection. Abdominal distention, anorexia, constipation, dyspepsia, and stomatitis have been reported in less than 1% of patients. GI upset has also been reported.

Hematologic

Hematologic side effects have included decreased hematocrit, decreased or increased white blood cells, decreased platelet counts, hemolysis, and hemolytic anemia. These reactions may also occur with a malaria infection.

Hypersensitivity

Hypersensitivity side effects have included allergic and anaphylactic reactions including facial edema and urticaria.

Dermatologic

Dermatologic side effects have included pruritus (2.6%) and rash (less than 1%).

Musculoskeletal

Musculoskeletal side effects have included rigors (1.7%), myalgia (1.3%), arthralgia (less than 1%), and back pain (less than 1%).

Nervous system

Nervous system side effects have included dizziness (4.5%) and headache (3%). Asthenia, confusion, convulsions, depression, paresthesia, and sleep disorder have been reported in less than 1% of patients.

Genitourinary

Genitourinary side effects have included urinary frequency (less than 1%).

Ocular

Ocular side effects have included abnormal vision (less than 1%).

Respiratory

Respiratory side effects have included cough (3%). Pulmonary edema has been reported (1/933); however, causality was not determined.

Other

Other side effects have included fatigue, malaise, and tinnitus in less than 1% of patients.

Hepatic

Hepatic side effects have included increased hepatic transaminases, which returned to normal within 2 to 3 weeks.

Renal

Renal side effects have included blackwater fever (acute intravascular hemolysis with acute renal failure and hemoglobinuria) requiring hemodialysis patients taking halofantrine for Plasmodium falciparum infections (n=2). Causality was not clearly established. One patient had a positive Coombs test.

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