How Genes Influence The Break Down Of Amprenavir

What Is Amprenavir?

Amprenavir is an antiviral drug used to treat the Human Immunodeficiency Virus (HIV) infection.

This drug was approved by the Food and Drug Administration (FDA) in 1999 and is available as capsules or oral solutions.

The drug is sold under the brand name Agenerase.

Is Amprenavir Still Available?

Amprenavir was discontinued in 2007.

However, a prodrug version of the same, called Fosamprenavir, is available now.

A prodrug is a substance that is converted into an active drug form in the body after the person consumes it. Sometimes when the actual drug is poorly absorbed or leads to severe side effects, a prodrug form of the same is developed.

The prodrug is created to ensure maximal absorption by the target cells and bring down the risk of adverse effects.

In this case, Fosamprenavir, on administration, is metabolized into amprenavir and directly targets the virus.

Is Amprenavir Available Over-The-Counter?

No. You will need a prescription to be able to buy the drug.

How Does Amprenavir Work?

Amprenavir belongs to a class of drugs called protease inhibitors. Protease is a type of enzyme that the virus makes.

This HIV-1 protease enzyme makes the virus infectious and, as a result, harmful.

Protease inhibitors attach themselves to the virus’s protease and prevent it from functioning. As a result, the virus remains infectious.

An adult will need 1200 mg of the drug twice a day, and the drug is available in the form of 50 mg or 150 mg capsules.

Side Effects Of Amprenavir

Some of the common side effects of amprenavir are:

Headache
Dizziness
Nausea
Stomach cramps
Diarrhea

About 27% of people may develop skin rashes and itchy skin when amprenavir is administered.

In addition, a severe skin condition called Stevens-Johnson Syndrome (losing the outer layer of the skin) may occur in 1% of people using the drug.

16% of people who use amprenavir may also experience psychiatric disorders, including mood swings and depression.

Amprenavir oral solution can lead to the following side effects:

Abnormally high heart rate
Seizures
Kidney failure

Like other protease inhibitors, Amprenavir may lead to increased cholesterol levels, insulin resistance, and worsening diabetes.

In General, Are Protease Inhibitors Safe?

Yes, protease inhibitors are safe to use under the guidance of a healthcare provider. However, make sure to talk to your doctor about your existing health conditions and the drugs you use to prevent the risk of side effects.

Interactions With Other Drugs

Amprenavir may interact with other drugs and lead to changes in drug efficacy or worsening of the adverse effects. Therefore, notify your doctor if you use amprenavir along with the following medications.

Alprazolam (used to treat panic disorders and anxiety)
Roxicodone, Methadone (opioid medications used to treat pain)
Dalmane (used to treat insomnia)
Metformin, Dulaglutide (used to treat type II diabetes)
Antiarrhythmic drugs (used to treat abnormal heart rate)
Rifabutin (antimycobacterial drug)
Rifampin (antibacterial drug used to treat tuberculosis)
Ketoconazole (antifungal drug)
Cisapride (used to treat gastroesophageal reflux disease)
Atorvastatin (used to treat high lipid levels)
Other HIV Protease Inhibitors

Amprenavir: Gene-Drug Interactions

SLCO1B1 Gene And Amprenavir

The SLCO1B1 gene (Solute Carrier Organic anion transporter family member 1B1 gene) provides instructions for producing the organic anion transporting polypeptide 1B1 (OATP1B1) protein.

This protein transports drugs, toxins, hormones, and other substances from the blood to the liver for elimination.

rs4149056 is a Single Nucleotide Polymorphism (SNP) in the SLCO1B1 gene.

In people with HIV infection, the CC and CT types of this SNP may lead to reduced blood amprenavir levels.

In contrast, TT type may lead to increased blood amprenavir levels.

However, this association was only found in people of European descent.

Low levels of amprenavir may not be sufficient to fight HIV effectively, while high drug levels may lead to an increased risk of developing adverse side effects.

Knowing specific gene changes can help plan the right drug dosage to maintain optimal drug levels in the body.

Genotype	Implications
CC	Decreased blood amprenavir levels in people of European descent with HIV
CT	Decreased blood amprenavir levels in people of European descent with HIV
TT	Increased blood amprenavir levels in people of European descent with HIV

Recommendations To Safely Use Amprenavir

Usage During Pregnancy And Breastfeeding

Studies in animals show that usage of amprenavir during pregnancy may be associated with an increased risk of abortion and low birth weight in babies.

Talk to your doctor and weigh the benefits and risks of using amprenavir if you are pregnant.

Animal studies also show that amprenavir is secreted in the milk of lactating animals. This is not confirmed in humans, though.

Hence, talk to your doctor and understand the risks of the same.

Doctors generally don’t recommend mothers with HIV to breastfeed because of the risk of postnatal transmission of the virus from the mother to the baby.

Usage In People With Existing Liver Conditions

People with existing liver conditions must use amprenavir with caution.

The Child-Pugh score is an assessment to determine the extent of liver damage.

People with a Child-Pugh score of 5-8 should bring down amprenavir dosage to 450 mg/twice a day.

Those with a score of 9-12 should decrease the dosage to 300 mg/twice a day.

Using Amprenavir Oral Solution

The oral amprenavir solution contains high amounts of propylene glycol. This colorless liquid is harmful in large doses.

Doctors recommend patients choose the capsules over the oral solution for this reason.

Also, the oral solution is not recommended for pediatric patients below four and the elderly.

Amprenavir And A High-Fat Diet

Studies show that a high-fat diet may decrease the absorption of amprenavir. Therefore, patients are advised to monitor their fat intake while on the drug.

Amprenavir And Birth Control Pills

Certain hormonal birth control pills can interfere with amprenavir and reduce its efficacy. Talk to your doctor if you are on birth control pills and are prescribed amprenavir.

Amprenavir Overdose

If you think you have overdosed on Amprenavir, make sure you call 911 or visit the nearest Emergency Room right away.

Genetic Testing

Genetic testing will help find out if you have SLCO1B1 gene changes. This can help plan the right dosage of amprenavir, preventing both lowered drug efficacy and drug overdose.

Analyze Your Genetic Response to Amprenavir

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Summary

Amprenavir is an antiviral medicine used to treat HIV infections.
Amprenavir belongs to the category of protease inhibitors and prevents viruses from maturing and getting infectious.
Some of the common side effects of amprenavir are headaches, nausea, dizziness, stomach cramps, and diarrhea.
Amprenavir can cause skin rashes and psychiatric disorders in a few people.
Amprenavir may interact with antibiotics, antifungal drugs, psychiatric drugs, opioid painkillers, and other protease inhibitors and lead to changes in drug efficacy or worsen the side effects.
SLCO1B1 gene changes can increase or decrease the levels of amprenavir found in the blood in HIV-infected people of European descent.
Pregnant and breastfeeding women and people with existing liver conditions should consume amprenavir with caution.
Combining amprenavir with a high-fat diet may reduce the absorption of the drug.
Genetic testing will help plan the correct dosages of amprenavir and avoid the risk of reduced drug efficacy and overdose.