Suramin

Key takeaways

Suramin belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Suramin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Suramin from memory before moving on to harder problems.

Reference excerpt

Suramin is a medication used to treat African sleeping sickness and river blindness. It is the treatment of choice for sleeping sickness without central nervous system involvement. It is given by injection into a vein. Common side effects include nausea, vomiting, diarrhea, headache, skin tingling, and weakness. Sore palms of the hands and soles of the feet, trouble seeing, fever, and abdominal pain may also occur. Severe side effects may include low blood pressure, decreased level of consciousness, kidney problems, and low blood cell levels. It is unclear if it is safe when breastfeeding. Suramin was made at least as early as 1916. It is on the World Health Organization's List of Essential Medicines. In the United States it can be acquired from the Centers for Disease Control (CDC). In regions of the world where the disease is common suramin is provided for free by the World Health Organization (WHO).

Medical uses Suramin is used for treatment of human sleeping sickness caused by trypanosomes. Specifically, it is used for treatment of first-stage African trypanosomiasis caused by Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense without involvement of central nervous system. It is considered first-line treatment for Trypanosoma brucei rhodesiense, and second-line treatment for early-stage Trypanosoma brucei gambiense, where pentamidine is recommended as first line. It has been used in the treatment of river blindness (onchocerciasis).

Pregnancy and breastfeeding It is unknown whether it is safe for the baby when a woman takes it while breastfeeding.

Adverse reactions The most frequent adverse reactions are nausea, vomiting, diarrhea, abdominal pain, and a feeling of general discomfort. It is also common to experience various sensations in the skin, from crawling or tingling sensations, tenderness of palms and the soles, and numbness of hands, arm, legs or feet. Other skin reactions include skin rash, swelling and stinging sensation. Suramin can also cause loss of appetite and irritability. Suramin causes non-harmful changes in urine during use, specifically making the urine cloudy. It may exacerbate kidney disease. Less common side effects include extreme fatigue, ulcers in the mouth, and painful tender glands in the neck, armpits and groin. Suramin uncommonly affects the eyes causing watery eyes, swelling around the eyes, photophobia, and changes or loss of vision. Rare side effects include hypersensitivity reactions causing difficulty breathing. Other rare systemic effects include decreased blood pressure, fever, rapid heart rate, and convulsions. Other rare side effects include symptoms of liver dysfunction such as tenderness in upper abdomen, jaundice in eyes and skin, unusual bleeding or bruising. Suramin has been applied clinically to HIV/AIDS patients resulting in a significant number of fatal occurrences and as a result the application of this molecule was abandoned for this condition.

Pharmacology

Pharmacokinetics Suramin is not orally bioavailable and must be given intravenously. Intramuscular and subcutaneous administration could result in local tissue inflammation or necrosis . Suramin is approximately 99-98% protein bound in the serum and has a half-life of 41–78 days average of 50 days; however, the pharmacokinetics of suramin can vary substantially between individual patients. Suramin does not distribute well into cerebral spinal fluid and its concentration in the tissues is equivalently lower than its concentration in the plasma. Suramin is not extensively metabolized and about 80% is eliminated via the kidneys.

Mechanism of action The mechanism of action for suramin is unclear, but it is thought that parasites are able to selectively uptake suramin via receptor-mediated endocytosis of drug that is bound to low-density lipoproteins and, to a lesser extent, other serum proteins. Once inside parasites, suramin combines with proteins, especially trypanosomal glycolytic enzymes, to inhibit energy metabolism.

Chemistry The molecular formula of suramin is C51H40N6O23S6. It is a symmetric molecule in the center of which lies a urea (NH–CO–NH) functional group. Suramin contains six aromatic systems – four benzene rings, sandwiched by a pair of naphthalene moieties – plus four amide functional groups (in addition to the urea) and six sulfonic acid groups. When given as a medication, it is usually delivered as the sodium sulfonate salt as this formulation is water-soluble, though it does deteriorate rapidly in air. The synthesis of suramin itself and structural analogs is by successive formation of the amide bonds from their corresponding amine (aniline) and carboxyl (as acyl chloride) components. Various routes to these compounds have been developed, including starting from separate naphthalene structures and building towards an eventual unification by formation of the urea or starting with a urea and appending successive groups.

History Suramin was first made by the chemists Oskar Dressel, Richard Kothe and Bernhard Heymann at Bayer AG laboratories in Elberfeld, after research on a series of urea-like compounds. The drug is still sold by Bayer under the brand name Germanin. The chemical structure of suramin was kept secret by Bayer for commercial and strategic reasons, but it was elucidated and published in 1924 by Ernest Fourneau and his team at the Pasteur Institute.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Suramin

Start with the simplest possible case. Write down what Suramin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Suramin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Suramin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Suramin

In research: Suramin appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Suramin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Suramin is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1916 in science, Anthelmintics, Antiprotozoal agents, so understanding it makes those chapters shorter.
In everyday life: Look for Suramin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Suramin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Suramin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Suramin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Suramin in simple terms?

Suramin is a medication used to treat African sleeping sickness and river blindness. It is the treatment of choice for sleeping sickness without central nervous system involvement.

Why does Suramin matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Suramin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Suramin.