What Is Suramin Used For?: History, Current Indications, and Research

October 6, 2025 •

4 min read

First synthesized in 1916, suramin is a century-old polysulfonated naphthylurea drug with primary indications for parasitic infections like African sleeping sickness and river blindness. However, its complex mechanism has prompted broad investigation into numerous other potential applications.

Quick Summary

Suramin is a long-standing antiparasitic medication used primarily for early-stage African sleeping sickness. Research explores its broader potential against viral diseases, cancer, and autism, but severe side effects limit many applications, and it is largely superseded for some conditions.

Key Points

Primary Parasitic Use: Suramin is a long-standing antiparasitic drug primarily used for the first stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense and T. b. gambiense.
River Blindness (Historical): The drug was historically used for river blindness but is largely replaced by less toxic alternatives like ivermectin due to its own side effects.
Antipurinergic Activity: A key mechanism of action is blocking purinergic receptors, which has led to its investigation for disorders involving chronic cellular stress, such as Autism Spectrum Disorder (ASD).
Anticancer Potential: Suramin inhibits growth factors and enzymes relevant to cancer, but its use as a cancer monotherapy is limited by high toxicity, with modern research focusing on its potential as a chemosensitizer.
Antiviral Research: It has demonstrated inhibitory effects against various viruses in vitro, including SARS-CoV-2 and HIV, although clinical use is hampered by safety concerns.
Significant Side Effects: The drug's severe side effect profile, including potential renal and neurological damage, limits its clinical utility for many indications.
Strict Administration: Suramin is only administered intravenously and requires close medical monitoring due to its toxicity and potential for serious adverse events.

The Primary and Historical Uses of Suramin

Suramin was developed by German chemists in 1916 and is one of the earliest examples of a modern chemotherapeutic agent derived from medicinal chemistry. Its initial and most well-established uses are as an antiparasitic agent for specific infectious diseases prevalent in Africa. These include Human African Trypanosomiasis (HAT) and Onchocerciasis (river blindness).

African Sleeping Sickness (Trypanosomiasis)

Suramin is the treatment of choice for the first, or hemolymphatic, stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense and can also be used for T. b. gambiense. It is effective for this initial stage before the parasite has invaded the central nervous system (CNS), as suramin cannot cross the blood-brain barrier. The drug works by inhibiting key enzymes within the parasite, disrupting its energy metabolism and leading to its death. Due to the severity of the disease, administration is done intravenously under strict medical supervision. However, high doses are toxic, and for some forms of HAT, alternatives like pentamidine are preferred.

River Blindness (Onchocerciasis)

Suramin is also active against the adult worms of Onchocerca volvulus, the parasite responsible for river blindness. Historically, it was a treatment option, but its significant toxicity and the development of less toxic, orally available alternatives like ivermectin have led to its replacement for routine use. It remains an option in cases of recurrent disease or ocular involvement where ivermectin is ineffective.

The Multifaceted Mechanism of Action

The reason for suramin's wide-ranging research potential lies in its "promiscuous" or multi-targeted mechanism of action, where it acts as a non-selective antagonist for various cellular components. It is a large, highly charged polyanionic molecule that interacts with numerous proteins and pathways.

Key Inhibitory Actions

Purinergic Signaling: Suramin is a potent antagonist of purinergic receptors (P2X and P2Y), which are activated by extracellular ATP. By blocking these receptors, it can dampen cellular stress and inflammatory responses, which is the basis for its investigation in conditions like autism.
Enzymatic Inhibition: The drug inhibits a host of enzymes crucial for cellular function, including kinases, phosphatases, and glycolytic enzymes, particularly in parasites.
Reverse Transcriptase: Early research identified suramin as an inhibitor of viral reverse transcriptase, leading to its testing for HIV in the 1980s. However, it was abandoned for this use due to severe toxicity and limited efficacy.
Growth Factors and Receptors: It can block the binding of growth factors like epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) to their receptors. This makes it of interest for anti-cancer research by inhibiting tumor growth and angiogenesis.

Areas of Ongoing and Historical Research

Suramin's broad activity has made it a subject of research for decades, exploring potential applications far beyond its established antiparasitic role. These investigations, while promising in initial studies, are often limited by toxicity.

Investigational Uses in Clinical Trials

Autism Spectrum Disorder (ASD): Research led by Dr. Robert Naviaux at UC San Diego has explored suramin's potential to treat core symptoms of ASD. The "cell danger response" (CDR) hypothesis suggests that chronic illness, including some forms of autism, involves persistent cellular stress signaling via purinergic pathways. A small 2017 Phase 1 trial showed temporary improvements in social interaction and language in a subset of autistic children after a single low-dose infusion. Larger trials are ongoing to investigate safety and efficacy with repeat dosing.
Cancer: Early clinical trials in the 1980s and 1990s studied suramin for various cancers, including hormone-refractory prostate cancer and adrenal cancer. While some studies showed modest anti-tumor effects, severe neurotoxicity and other side effects limited its utility as a monotherapy. Research now considers suramin as a chemosensitizer in combination with other drugs.
COVID-19 and Other Viruses: Following the SARS-CoV-2 pandemic, studies identified suramin's ability to inhibit viral replication in cell culture by interfering with the RNA-dependent RNA polymerase. It also showed activity against other viruses, including HIV, Ebola, and Zika. However, as with cancer and HIV, toxicity concerns necessitate further research for safe human use.

Potential Applications and Limitations of Suramin


Feature	Primary Parasitic Uses	Investigational Research Areas
Indications	Early-stage African sleeping sickness (T. b. rhodesiense); second-line for early T. b. gambiense; adult O. volvulus	Autism Spectrum Disorder (ASD), various cancers, viral infections (e.g., COVID-19, Ebola), snakebite envenomation
Mechanism of Action	Inhibits parasite glycolytic enzymes, blocking energy production	Antagonist of purinergic receptors, inhibitor of growth factors, reverse transcriptase, and RNA polymerase
Toxicity Profile	Significant systemic toxicity, including renal damage, fever, vomiting, and potential for anaphylaxis	Dose-limiting neurotoxicity (peripheral neuropathy) observed in cancer trials; transient side effects in low-dose ASD trials
Administration	Intravenous injection only; requires careful hospital monitoring	Intravenous injection for clinical trials; requires careful monitoring
Current Status	Approved and available for specific parasitic diseases, often via CDC access in the US	Highly experimental; requires extensive research to establish safety and efficacy for new indications

Conclusion

Suramin remains a unique and powerful polyanionic molecule with a century-long history, starting with its groundbreaking success against African sleeping sickness. While its efficacy against parasitic diseases is well-established, its significant toxicity and intravenous-only administration have limited its widespread use, especially as newer, safer drugs have been developed for conditions like river blindness.

Despite these limitations, its broad inhibitory activity against multiple cellular pathways has positioned suramin as a subject of intense scientific curiosity and repurposing efforts. From autism to cancer and viral diseases, researchers are still exploring its potential, although often requiring lower doses to mitigate side effects. The history of suramin serves as a powerful illustration of how a single compound can have a complex and evolving medical legacy, with its journey from life-saving parasite treatment to an investigational tool in diverse modern diseases still unfolding.

For more detailed information, the National Institutes of Health (NIH) provides access to scientific reviews on suramin's history and multifactorial effects on various cellular targets and pathologies.(https://pmc.ncbi.nlm.nih.gov/articles/PMC7038244/)

Frequently Asked Questions

Suramin's main approved medical use is the treatment of the early, hemolymphatic stage of African sleeping sickness (trypanosomiasis), specifically caused by Trypanosoma brucei rhodesiense.

Suramin cannot cross the blood-brain barrier, making it ineffective for treating the late, neurological stage of African sleeping sickness where the parasite has invaded the central nervous system.

While effective against the adult worms of Onchocerca volvulus, suramin is no longer the primary treatment for river blindness due to its significant toxicity. Safer alternatives, such as ivermectin, are now preferred.

Suramin works by disrupting the energy metabolism of parasites, causing them to lose energy and eventually die. It is known to inhibit various glycolytic enzymes crucial for the parasite's survival.

The cell danger response (CDR) hypothesis suggests that chronic illnesses like ASD involve persistent cellular stress. Suramin, by acting as an antipurinergic agent, can inhibit the purinergic signaling pathway, potentially helping to reset cellular function and improve symptoms.

Although suramin showed some anti-tumor activity in trials, its use was hampered by dose-limiting neurotoxicity and other severe side effects. It is now primarily considered for its potential as a chemosensitizer rather than a standalone cancer therapy.

No, in regions like the United States, suramin is not approved for general use. It can only be obtained for its approved indications for rare parasitic diseases via entities like the Centers for Disease Control (CDC).