Active Ingredients

Sorivudine – Effect, Application & Risks


Sorivudin is a medical drug developed in Japan to treat herpes . Sorivudine was marketed under the trade name Usevir® and has been unavailable since a drug scandal that left several people dead in Japan. In Europe, there was no approval at all, so the preparation did not have to be withdrawn from the market.

What is sorivudine?

Sorivudine was developed by the Japanese pharmaceutical company Nippon Shoji in the early 1990s. The active ingredient was used to treat herpes infections and acted as an antiviral . This includes medicines that inhibit the multiplication of viruses and thus enable the therapy of infectious diseases .

Sorivudin is effective against infections caused by the herpes simplex type 1 virus. There was also an indication for the Epstein-Barr virus (often also called EBV or HHV4).

Sorivudine is described in chemistry and pharmacology by the empirical formula C 11 – H 13 – Br – N 2 – O 6 and has a moral mass of 349.13 g/mol. After Usevir®, the most important sorivudine-containing preparation, triggered a national drug scandal in 1994, the substance was withdrawn from the market. Since then, it has no longer been available worldwide as a medicinal product and is not used in human medicine.

Pharmacological action

Sorivudine achieves its effectiveness against herpes and Epstein-Barr viruses by inhibiting the enzyme dihydropyrimidine dehydrogenase (DPD). Among other things, this is responsible for the breakdown of various pyrimidines and fluorouracil . Fluorouracil, often also called 5-FU or 5-fluorouracil, is a cytostatic . As such, the substance is given as part of a comprehensive chemotherapy regimen to treat various cancers .

Due to the inhibition of DPD caused by sorivudine, the breakdown of fluorouracil is made impossible or considerably slowed down, which can be lethal under certain circumstances. So there are massive interactions between sorivudine and fluorouracil.

Sorivudine itself is broken down in the body by bromovinyluracil. The degradation process thus largely corresponds to that of the antiviral brivudine , which is still approved as a drug.

Medical Application & Use

Sorivudine was administered and manufactured to treat herpes. The preparation Usevir® was indicated to treat infections with herpes zoster (shingles) or herpes simplex type 1. Epstein-Barr viruses could also be treated with sorivudine. It was taken orally in the form of film-coated tablets. Preparations containing sorivudine were subject to pharmacy and prescription requirements in Japan.

Sorivudine was withdrawn from the market after a drug scandal in Japan. Because of the drug’s mode of action, a total of 16 patients died after taking sorivudine in 1994 because they had been previously treated with fluorouracil. This was possible because Nippon Shoji, the manufacturer of the sorivudine, provided inaccurate information to the responsible Ministry of Health during the approval process. Because even when carrying out the necessary drug tests in advance, there were deaths caused by the known interaction of fluorouracil and sorivudine. Since the manufacturer failed to pass on the necessary information after the end of the test phase, Sorivudine was approved. There was no indication of the lethal interaction,

Risks & side effects

Sorivudin must not be taken if intolerance or allergies to the drug are known. These can manifest themselves in severe skin reactions such as itching , redness or rashes . The drug can also cause headaches and general malaise as an undesirable side effect . Symptoms of the gastrointestinal tract are also conceivable.

Sorivudine leads to massive interactions with fluorouracil, since the breakdown of the cancer drug is inhibited by sorivudine. This can potentially be fatal. From a medical point of view, this is a contraindication, so that a combined administration of fluorouracil and sorivudine must be avoided.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.