Herpes medication can cause serious interactions
A Red Hand letter warns of the potentially fatal interactions between herpes drugs from the class of brivudine-containing drugs and so-called fluoropyrimidines. Under no circumstances should brivudine and fluoropyrimidine be taken at the same time.
There must be a gap of at least four weeks between the use of brivudine and fluoropyrimidines in order to avoid potentially fatal interactions, warn the marketing authorization holders of medicines containing brivudine in consultation with the European Medicines Agency (EMA). A corresponding red hand letter was published on the website of the Federal Institute for Drugs and Medical Devices (BfArM).
Brivudine and fluoropyrimidines
Medicines with brivudine are used against the herpes simplex type 1 virus (trigger of cold sores) and herpes zoster (trigger of shingles). Fluoropyrimidines are used in cancer therapy, but also in the treatment of fungal infections. If both active ingredients are taken in parallel, this can have fatal consequences.
Fluoropyrimidine toxicity greatly increased
Brivudin inhibits dihydropyrimidine dehydrogenase (DPD), an enzyme that metabolizes pyrimidine-based drugs such as fluorouracil, capecitabine, tegafur and flucytosine, via its main metabolite bromovinyl uracil (BVU). Thus, inhibition of DPD leads to an increased level of fluoropyrimidines, which increases fluoropyrimidine toxicity to such an extent that it is potentially fatal.
Interaction with impending deaths
"Deaths can occur as a result of drug interactions between brivudine and fluoropyrimidines (e.g. fluorouracil (5-FU), capecitabine, tegafur, flucytosine)," the clear warning in the Red Hand letter. Therefore, the technical information, package leaflet and labeling of the outer carton will be revised accordingly, in order to indicate even more the compliance with the 4-week interval between treatment with brivudine and fluoropyrimidines.
A patient card with the most important information for patients and healthcare professionals should also be included with each pack and a checklist for prescribing doctors should be provided.
Who Shouldn't Get Brivudine?
According to the Red Hand Letter, brivudine is contraindicated in patients
- who have recently received, are currently receiving, or are due to receive cancer chemotherapy within four weeks of medicinal products containing fluorouracil, including its topical preparations, prodrugs (e.g. capecitabine, tegafur), and combination products containing one of these agents or other fluoropyrimidines .
- who have recently received or are currently receiving antifungal therapy with flucytosine; because a small amount of flucytosine is converted to fluorouracil.
- who are immunodeficient, such as those who have recently had cancer chemotherapy.
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Dipl. Geogr. Fabian Peters
- Federal Institute for Drugs and Medical Devices (BfArM): Rote-Hand-Brief on brivudine-containing drugs: Potentially fatal toxicity of fluoropyrimidines when used shortly before, simultaneously with or within 4 weeks after the end of treatment with brivudine (published May 13, 2020), bfarm .de