How Genes Influence The Breakdown Of Adefovir?

What Is Adefovir?

Adefovir is a medication used to treat people with chronic hepatitis B infection. This belongs to a group of drugs called nucleotide analogs.

Nucleotide analogs represent a major class of antiviral drugs.

This is an oral pill that has to be taken regularly for a specific period of time.

It is prescribed for adults and children older than 12.

It is commonly sold under the brand name Hepsera.

How Does Adefovir Work?

Adefovir works by blocking an enzyme called reverse transcriptase in the body.

The Hepatitis B Virus (HBV) needs this enzyme to replicate in the body.

By blocking the enzyme, the drug can prevent the virus from multiplying and growing in the body.

This drug cannot cure hepatitis B or protect from its side effects.

It may also not be effective in preventing the spread of the disease from the infected person to others.

Adefovir only reduces the viral load.

Side Effects Of Adefovir

Some common side effects of adefovir are:

Weakness
Headaches
Nausea
Vomiting
Cough
Indigestion
Sore throat

Some of the more severe side effects of adefovir are:

Seizures
Breathing difficulties
Fainting episodes

Some people rarely develop allergic reactions to adefovir.

Contact your doctor if you experience any allergic symptoms after consuming the drug.

Allergic symptoms include the below:

Rashes
Swollen tongue and lips
Itching
Breathing difficulties

Interactions With Other Drugs

Adefovir can interact with many other drugs and can lead to serious side effects or reduced efficacy of the drugs.

Consult your doctor if you take one or more of the below medications:

Cidofovir (antiviral medications)
Non-Steroidal Anti-Inflammatory Drugs (anti-inflammatory medicines)
Viread, Antiretrovirals, Complera (a combination of emtricitabine, rilpivirine, and tenofovir drugs), Stribild, and Emtricitabine/Tenofovir (used to treat HIV infections)

Gene-Drug Interactions: Adefovir

SLC22A6 Gene And Adefovir

Once it reaches the body, adefovir is not cleared by the Cytochrome P450 enzymes like most drugs.

The drug also does not bind to the plasma or serum proteins. Instead, it is cleared by the kidneys.

The SLC22A6 gene (solute carrier family 22 member 6) contains instructions for the production of the SLC22A6 protein, also called the Human Organic Anion Transporter 1 (hOAT1) protein.

This protein is found in the proximal tubular cells of the kidneys. It plays a role in the clearance of drugs like adefovir by taking them to the kidneys.

Changes in the SLC22A6 gene can lead to over-exposure of the kidneys to the adefovir drug and may cause renal toxicity.

rs11568634 is a Single Nucleotide Polymorphism (SNP) in the SLC22A6 gene.

People with the CC genotype of this SNP may have increased uptake of adefovir dipivoxil compared to those with the CT and TT genotypes.

Genotype	Implications
CC	Increased uptake of adefovir dipivoxil
CT	Normal uptake of adefovir dipivoxil
TT	Normal uptake of adefovir dipivoxil

Antiviral-Induced Fanconi Syndrome

Adefovir blocks nucleic acid synthesis in the body.

Nucleic acid is a molecule found in all cells and viruses and includes DNA and RNA.

As a result, the OAT1 proteins are not able to effectively eliminate the drug from the body.

This leads to drug buildup in the proximal tubule cells of the kidneys.

This buildup damages these cells and can lead to renal impairment, leading to antiviral-induced Fanconi syndrome.

Changes in the SLC22A6 gene increase the risk of this problem.

Though rare, studies show that this is a possibility that doctors should monitor in patients treated with adefovir or other antiviral medications.

Recommendations To Safely Use Adefovir

Discontinuing The Medication

People who discontinue the medication without instructions from a doctor can experience life-threatening symptoms, including death.

Do not discontinue or change drug dosages without consulting your doctor.

Drug Overdose

Adefovir overdose can lead to kidney problems, seizures, and unconsciousness.

Call emergency medical services right away if you suspect an overdose of the drug.

Patients With Liver Transplantations

People who have had prior liver transplant surgeries or other liver disorders may experience renal failures, and their conditions have to be monitored regularly.

A study analyzed the effect of adefovir in 467 individuals with pre and post-liver transplant surgeries.

According to the study, 4% of patients had to discontinue adefovir because of adverse side effects.

Genetic Testing

Genetic testing will help understand the impact of adefovir on the kidneys and help plan dosages better.

Analyze Your Genetic Response to Adefovir

Summary

Adefovir helps treat people infected with the hepatitis B virus. This belongs to a group of drugs called nucleotide analogs and is prescribed for people older than 12.
Adefovir works by blocking the reverse transcriptase enzyme in the body and preventing the virus from multiplying and growing.
Adefovir may not help treat the symptoms of the disease. It only brings down the viral load.
Some of the common side effects of adefovir are weaknesses, headaches, gut problems, cough, and sore throat.
Adefovir overdose may lead to seizures, unconsciousness, and breathing difficulties.
Adefovir can interact with many other drugs and lead to severe side effects. Talk to your doctor about drug interactions.
Changes in the SLC22A6 gene can lead to drug buildup in the proximal tubular cells of the kidneys. This can cause increased uptake of Adefovir and possible renal impairment.
Discontinuing the medication without a doctor’s advice can lead to severe symptoms, including death.
People with existing renal and liver conditions have to exercise caution when taking Adefovir.
Rarely, some people who consume Adefovir can experience allergy symptoms.
Genetic testing will help understand the impact of adefovir on the kidneys, making dosage planning more effective.