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Nucleoside Analogues – Effect, Application & Risks

Nucleoside

nucleoside analogue is a substance that resembles a natural nucleoside . In particular, these are drugs that are used for antiviral treatment (so-called nucleoside reverse transcriptase inhibitors, NRTI). Nucleoside analogues therefore play an important role in the treatment of infectious diseases such as HIV , hepatitis B (HBV) or hepatitis C (HBC).

What are nucleoside analogues?

The term nucleoside analogue is a collective term in human medicine and pharmacology . This refers to various substances that show similarities to the natural nucleosides. A nucleoside is a combination of a nucleobase and pentose, which is an important part of nucleic acid (an essential element of DNA ). Nucleoside analogs therefore resemble the building blocks of genetic material.

Due to these properties, they manage to suppress the reproduction of viruses . This reduces the viral load in the body, which leads to noticeable improvements in the specific symptoms of the disease.

The most important nucleoside analogues include the drugs ribavirin , zidovudine , abacavir , tenofovir , didanosine , stavudine and lamivudine . They are used to treat HIV, hepatitis B (HBV) or hepatitis C (HBC).

Pharmacological effect on body & organs

The effectiveness of nucleoside analogs is essentially based on their structural similarity to the components of the genetic material. The corresponding substances are absorbed by the cell and only develop a relevant effect through phosphorylation that takes place within the cell. In this process, the cell converts the nucleoside analog step by step into phosphate residues.

The analogues become part of the generated DNA as “wrong” components. This leads to a disruption of an otherwise properly assembled DNA chain, causing the polymerization to stop . The reverse transcription of the cell is stopped and the virus cannot multiply any further. After some time, this leads to a significant reduction in the viral load in the body.

Medicinal Application & Use for Treatment & Prevention

The field of application of the nucleoside analogues is the therapy of viral infections. The most important area is the treatment of HIV and hepatitis B (HBV). The development of nucleoside analogs marked the beginning of modern combination treatment, which led to significant therapeutic success.

With modern preparations of the younger generation, the application takes place once a day in the form of film-coated tablets for oral administration. Nucleoside analogues are thus easy for the patient to take themselves. The nucleoside analogues staduvin, cytidine, zidovudine, lamivudine, abacavir, and inosine are currently available for the treatment of HIV infection .

Nucleoside analogs have only been available to treat hepatitis B (HBV) since the early 2000s. Previously, the drug lamivudine, developed to treat HIV infection, and the somewhat younger adefovir were administered. Modern treatment approaches, on the other hand, rely on nucleoside analogues. Specifically, the drugs tenofovir and entecavir are administered. Doctors hope that this will result in less resistance developing and greater success in long-term therapy. Nucleoside analogues are combined with other substances to combat HBV.

Within the European Union and the United States of America there is a strict prescription and pharmacy obligation, so that it can only be obtained with a doctor’s prescription.

Risks & side effects

Although nucleoside analogues are considered to be well tolerated, taking them is not free of risks and side effects . Gastrointestinal complaints often occur after use . Patients report an unreasonable feeling of fullness , nausea , vomiting and diarrhea (diarrhea). In addition, general malaise and headaches can also occur.

In addition, long-term side effects are also conceivable, which only become apparent after several years of use. The occurrence of pancreatitis , myelotoxicity, polyneuropathy , lactic acidosis and lipoatrophy is common . This is probably due to the fact that nucleoside analogs are toxic to mitochondria . However, the intensity of the toxic effects depends on the preparation used.

Patients who are allergic to the nucleoside analog used must refrain from taking it, as there is a medical contraindication.

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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.