What is adefovir?Adefovir is a medicine used to treat hepatitis B. If taken long-term, it prevents the proliferation of hepatitis B viruses.
Adefovir, also known as adefovirum, belongs to the class of antiviral drugs. These are drugs that inhibit the multiplication of viruses.
Adefovirum was approved in the European Union in 2003. It is prescribed to adults for the treatment of chronic hepatitis B. In most cases, the drug is only used when there is additional liver disease. This may be a disorder of serum levels or liver inflammation.
The drug is sold in Germany under the name Hepsera. The half-life of the drug is seven hours, after which it is degraded via the kidney. In the blood adefovir is only slightly bound by proteins.
In medical circles adefovir is classified as a prodrug. This is an initially inactive active substance, which develops its effect only after ingestion. After ingestion, adefovir is converted to a transitional state into adenosine monophosphate.
The phosphate forms a related structure, but it is better absorbed by affected cells. There it is finally converted to adefovir diphosphate and assumes its active form. Within the cell, the adefovir diphosphate collides with the naturally occurring substrate deoxyadenosine triphosphate. Since both compounds are very similar, they inhibit nucleic acid synthesis. As a consequence, the affected cell is prevented from dividing.
Overall, the rate of propagation of viruses is reduced. Colloquially, this method is also referred to as suicide inhibition. Since the human DNA polymerase can be stopped with this method, only low concentrations of the active ingredient may be taken. Incidentally, a continuous increase in resistance can be observed during treatment.
This is due to a mutation of a polymerase gene. In the long term, the clinically observed resistance can minimize treatment success. Therefore, a reduction in viral load is only possible in the short term. Usually this is sufficient, however, to prevent further liver damage.
Medical application & use
Adefovir is a prescription medicine. It is used exclusively for the treatment of chronic hepatitis B disease. The drug represented in Germany Hepsera contains the active ingredient in the form of tablets. These are taken orally according to the doctor's instructions. It can be expected with a bioavailability of about 60 percent. This means that the proportion of active ingredient is 60 percent of the total.
However, the drug is associated with low protein binding. Thus, less than four percent of the intake is available to the circulation. Adefovir is excreted after a few hours. This is done via the kidney through filtration and secretion. This can be expected with a half-life of seven hours. Accordingly, leaves half of the absorbed drug amount after every seven hours the body.
However, it should be noted that the use of the drug is prescribed only in combination with a pending or ongoing liver disease. In addition, active virus replication must be demonstrated. This means that the progression of a hepatitis B disease should be checked for initial or follow-up treatment. Depending on the medical history, any exceptions apply.
Risks & Side Effects
Adefovir is associated with a number of side effects in the treatment. The most important side effects include nephrotoxin. It is colloquially referred to as kidney toxins. The naming goes back to the toxic effect of the drug, especially against kidney cells.
Therefore, kidney function must be checked at regular intervals. If a restriction is found, the doctor may adjust the recommended dose. In addition, gastrointestinal complaints may occur. These are disorders of the digestive system. If taken for a long time, headache and neck pain may be added.
These leave after the end of treatment again. Furthermore, adefovir is unsuitable for underage and pregnant patients. Under certain circumstances, a benefit-risk assessment can be made. Often, the consequences of therapy outweigh the associated treatment success. It is still unknown whether the agent occurs in breast milk. As a precaution, breast-feeding should be avoided throughout the duration of treatment.