suramin

Suramin is a medication intravenously (IV) administered to treat sleeping sickness, also known as African trypanosomiasis caused by microscopic parasites of the species Trypanosoma brucei.

Two subspecies of the parasite cause disease in humans, one that progresses slowly caused by T. b. gambiense found in western and central Africa, and a more acute infection caused by T. b. rhodesiense found in eastern and southern Africa.   

The Trypanosoma parasites live in the gut of the Glossina species of tsetse fly found in sub-Saharan Africa, and transmitted when the tsetse fly bites humans for a blood meal. There are no vaccines or drugs for the prevention of African trypanosomiasis and protective measures against being bitten by tsetse flies are the only way to prevent infection.

Once the Trypanosoma parasites enter the skin tissue from the tsetse fly saliva, they get into the lymphatic system and bloodstream and start multiplying. In the second stage, the parasites enter the cerebrospinal fluid and affect the brain and central nervous system. Suramin is used to treat only the initial blood and lymphatic (hemolymphatic) stage, because it does not cross the blood-brain barrier.

It is not clear how exactly suramin kills the Trypanosoma parasites, it is believed that the trypanocidal effects may be because suramin inhibits enzymes involved with the oxidation of reduced nicotinamide-adenine dinucleotide (NADH). NADH is an important coenzyme essential for cellular respiration and breakdown of glucose (glycolysis) into energy in the parasite.

In addition to African trypanosomiasis, suramin has been also used to treat river blindness (onchocerciasis) caused by the parasitic worm Onchocerca volvulus, but the drug has now been replaced with the less toxic ivermectin. Suramin is also being investigated for use in other parasitic infections including malarial parasite Plasmodium falciparum, viral infections including hepatitis, human immunodeficiency (HIV), herpes simplex, dengue, zika and other viruses, cancers and as an antidote for venomous snakebites.

Suramin is not commercially available in the US. It is available for the treatment of patients with African trypanosomiasis through the Centers for Disease Control (CDC) Drug Service to be used under an Investigational New Drug (IND) protocol.

• Suramin may cause severe hypersensitivity reactions including shock and loss of consciousness. Use suramin with caution and avoid use in patients with a history of hypersensitivity reactions.
• Suramin is toxic to the kidneys and may impair kidney function. It is associated with excessive protein excretion in the urine (proteinuria).
• Avoid using suramin in patients with impaired kidney or liver function.
• Suramin has severe reactions in patients with coinfection of trypanosomiasis and onchocerciasis. Screen patients for coinfection with onchocerciasis and consider using alternate therapy in such patients.

Common side effects of suramin include:

• Shock
• Dizziness
• Fatigue
• Headache
• Loss of consciousness
• Peripheral nerve damage (neuropathy)
• Numbness and tingling (paresthesia)
• Nausea
• Diarrhea
• Vomiting
• Oral inflammation (stomatitis)
• Fever
• Increased thirst (polydipsia)
• Kidney toxicity (nephrotoxicity)
• Excessive urination (polyuria)
• Excessive protein in the urine (proteinuria)
• Kidney impairment
• Optic atrophy
• Low count of all types of blood cells (pancytopenia)
• Immediate hypersensitivity reactions
• Skin reactions including:
  • Hives (urticaria)
  • Itching (pruritis)
  • Inflammation and peeling skin (exfoliative dermatitis)

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Powder for Injectable Solution

• 1 g (reconstitute to 100 mg/mL)

Adult:

Trypanosomiasis

• Adult: 100-200 mg (test dose) intravenously (IV), then 1 g IV on days 1, 3, 7, 14, 21

TB Gambiense

• 10 mg/kg IV every 5 days to a total of 12 injections
• May repeat after 1 month; use concomitantly with tryparsamide

Pediatric:

Trypanosomiasis

• 20 mg/kg IV on days 1, 3, 7, 14, 21; not to exceed 1 g/dose

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Suramin has no known severe, serious, moderate or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

• There are no human studies on suramin use during pregnancy. Animal studies show evidence of congenital malformations.
• Untreated trypanosomiasis is fatal and suramin treatment should not be withheld from pregnant women, although the drug is toxic.
• There is a report of one pregnant traveler who contracted trypanosomiasis and was treated with suramin, giving birth at term to a healthy baby.
• Pregnant women should avoid travel to trypanosomiasis-endemic regions and those living around tsetse fly infested areas should take precautions to prevent being bitten.
• It is not known if suramin is present in breast milk. Use with caution in nursing mothers.