Mesna stands as an abbreviation for sodium 2-mercaptoethanesulfonate. This is an active ingredient that can be used to support chemotherapy. Mesna is thought to help the body by rendering toxic metabolites harmless, thereby reducing the risk that the patient will develop a serious complication as a result of chemotherapy.
What is mesna?
Mesna is a drug that can be used as an adjuvant to chemotherapy. Mesna (more rarely spelled MESNA) is a short form for the pharmacologically active substance sodium 2-mercaptoethanesulfonate with the molecular formula C2H5NaO3S2. In its pure form it has an irritant effect and therefore requires careful handling. Mesna belongs to the class of antidotes and cough expectorants that liquefy bronchial mucus (mucolytics). In 2008, the approval for mesna as a mucolytic expired; prior to that, it was used for bronchial obstruction, bronchiectasis, cystic fibrosis, and other conditions. Mesna is formed from the combination of 2-bromoethanesulfonic acid and thiourea, which is formed from urea when a sulfur atom displaces the oxygen atom of urea.
Pharmacological action
The mesna molecule has a sulfhydryl group at one end, through which it can form a compound with the toxic substance acrolein. The EU hazard label classifies acrolein, among other substances, as very toxic. It is formed when cyclophosphamide or another oxazaphosphorine is needed to fight cancer cells. Acrolein thus poses a major problem for chemotherapy, because without an antidote such as mesna, the dose for treatment with cyclophosphamide is not based on need alone. Instead, physicians must limit the dose of the chemotherapy drug to keep acrolein’s toxic effects under control. Mesna shifts the balance in favor of the patient. Without the drug, Acrolein would potentially cause an inflammation of the bladder with bleeding, called hemorrhagic cystitis. In addition to a significant amount of blood in the urine, hemorrhagic cystitis may manifest as frequent, painful or burning urination and bladder cramps. Abdominal pain, fever or urge incontinence may also occur. Untreated cystitis can develop into renal pelvic inflammatory disease, which often presents with symptoms such as pressure pain in the kidney area, nausea, dizziness, fever or headache. In the worst cases, the infection spreads further and ends in a specific form of blood poisoning called urosepsis, in which blood vessels are damaged and a life-threatening condition can occur. The mortality rate for urosepsis ranges from 13 to 43%, depending on the form present.
Medical application and use
Mesna may be used in certain chemotherapies to treat cancer. The substance does not act directly on the neoplasms or metastases, but supports the therapy by rendering toxic metabolic products harmless. These harmful substances are formed as a result of the actual chemotherapy. However, doctors cannot use Mesna at will to dampen general side effects of various chemotherapies. The drug neutralizes only one specific toxic metabolite with which it can form a chemical bond, acrolein. Mesna is available as an antidote under the trade names Mistabronco and Uromitexan. Patients usually receive the latter as an infusion during and after the actual chemotherapy. To allow acrolein to leave the body, patients should consume plenty of fluids. It may also be necessary to monitor excretions to ensure that no bodily functions are impaired and that the fluid, in combination with mesna, flushes out the toxins as intended. Usually, the body excretes the drug very quickly.
Risks and side effects
Side effects of Mesna in rare cases include symptoms such as skin reactions, water retention (edema), mucous membrane symptoms, drop in blood pressure, and heart palpitations (tachycardia). High doses may additionally cause headache, fatigue and lack of strength, nausea, vomiting, and aching limbs. However, it is unclear whether some of the symptoms are due to the chemotherapy and not to mesna.Some people are hypersensitive to mesna and develop various skin reactions that may also affect the mucous membranes. Circulatory problems may also manifest. In case of hypersensitivity, mesna is therefore contraindicated as long as the potential benefits do not outweigh the risks. However, this decision depends on the individual case.
