Abacavir Sulfate - Uses, Dosage, Warnings, and Side Effects

Overview

Abacavir sulfate is the sulfate salt of abacavir, which is an analog of guanosine and belongs to the class of nucleoside reverse transcriptase inhibitors. This medication is effective in reducing HIV viral loads, preventing immune system damage, and lowering the risk of AIDS. Abacavir sulfate is an aza heterocyclic sulfate salt. It has a functional similarity to abacavir, an HIV-1 reverse transcriptase inhibitor. It is prescribed by healthcare providers and approved by the FDA for the treatment of HIV in adults, children, and infants, always in combination with other HIV medicines.

Abacavir (ABC) is a synthetic carbocyclic nucleoside. It is a potent nucleoside analog reverse transcriptase inhibitor (NRTI). It is prescribed for the treatment of HIV and AIDS. It has a 1S, 4R, absolute configuration on the cyclopentene ring. Upon administration, Abacavir sulfate breaks down into Abacavir, its free base, in the body.

How Does Abacavir Sulfate Work?

Abacavir is an effective medication used for the treatment of HIV and AIDS as a nucleoside analog reverse transcriptase inhibitor (NRTI). This medication is classified as a nucleoside analog, meaning that it imitates one of the DNA's building blocks required by the virus for replication. It belongs to the synthetic carbocyclic nucleoside family and has a specific configuration on the cyclopentene ring, with the enantiomer having an absolute configuration of 1S, 4R. Upon administration, abacavir sulfate separates into its free form, abacavir, in the body.

Abacavir sulfate functions by hindering the function of the reverse transcriptase enzyme, which is responsible for the replication of the human immunodeficiency virus (HIV) that causes AIDS. When Abacavir becomes a part of the viral DNA, it hampers the action of reverse transcriptase, which prevents the virus from proliferating. This aids in decreasing the amount of virus in the body and slowing down the advancement of HIV infection. In combination with other antiretroviral drugs, Abacavir sucralfate is given as part of a complete HIV and AIDS treatment regimen.

What Are the Uses of Abacavir Sulfate?

Abacavir does not provide a cure for HIV, but it can help lower the risk of developing acquired immunodeficiency syndrome (AIDS) and related conditions such as cancer or severe infections. Employing these medicines in conjunction with safe sexual practices and lifestyle modifications can minimize the likelihood of transmitting (spreading) the HIV virus to others.

Dosage:

Abacavir sulfate is used in the form of a tablet and oral solution.

Warning:

Abacavir has the power to cause a severe or life-threatening allergic reaction. In case of the following, one or more symptoms from the below groups, immediately contact the health care provider to determine if there is a need to stop taking the medication:

Group 1: Fever.

Group 2: Rash.

Group 3: Nausea, stomach pain, vomiting, or diarrhea.

Group 4: Feeling unwell, extreme fatigue, or achiness.

Group 5: Cough, sore throat, and shortness of breath.

Allergic Reaction - Certain individuals may have a higher likelihood of experiencing an allergic reaction to Abacavir based on their hereditary or genetic makeup. The doctor performs a lab test to know if the patient is more prone to an allergic reaction to Abacavir. Do not take Abacavir or any other medication containing Abacavir again if an allergy is present.

Hypersensitivity Reaction - Hypersensitivity reactions may occur if the patient tests positive for the HLA-B*5701 allele.

For Patients:

Learn About HIV Infection

What Is an HIV Infection?

The human immunodeficiency virus (HIV) infection decreases the body's immunity as the virus attacks it. HIV can progress to acquired immunodeficiency syndrome (AIDS) if not treated accordingly. Unfortunately, there is no known cure for HIV, and once a person is infected, they will have the virus for life. However, HIV can be managed effectively with proper medical care. Individuals with HIV who receive effective treatment can lead healthy, prolonged lives and prevent transmission of the virus to their partners.

What Is AIDS?

AIDS (acquired immunodeficiency syndrome) occurs when the immune system is severely damaged by the immunodeficiency virus. A person is considered to have AIDS when their CD4 cell count falls below 200 cells/mm3 (compared to 500-1600 cells/mm3 normal, healthy immune system). Taking prescribed HIV medication prevents most people with HIV from progressing to AIDS. Without HIV medication, people with AIDS typically survive only about 3 years, and life expectancy falls to about one year once they develop a dangerous opportunistic illness. However, HIV medication can still be lifesaving at this stage of the disease. Starting HIV medication soon after contracting the virus provides more benefits, which is why HIV testing is crucial.

What Are the Symptoms of HIV?

In many cases, yes, individuals may experience flu-like symptoms within two to four weeks after contracting HIV. These symptoms can last for a few days or several weeks. However, it is important to note that experiencing flu-like symptoms alone does not necessarily mean that one has HIV, as other illnesses can cause similar symptoms. The only way to know if the patient has HIV is to get it tested.

Learn More About Abacavir Sulfate:

What Is the Action of Abacavir Sulfate on the Body?

Abacavir sulfate works by inhibiting the replication of the HIV virus, which helps to slow down the damage caused to the immune system. As a result, it may delay the onset of severe health issues that are commonly associated with HIV or AIDS. However, it should be noted that Abacavir sulfate is not effective in preventing the transmission of HIV to other individuals. Patients receiving this medication may still experience other complications related to HIV or AIDS.

How Effective Is Abacavir Sulfate?

Abacavir sulfate can be effective in reducing the amount of HIV in the blood and slowing down the progression of the disease when taken as prescribed. The effectiveness of Abacavir sulfate can vary depending on factors such as the individual's immune system and the stage of HIV infection.

Things to Tell Physicians Before They Prescribe Abacavir Sulfate:

• Inform the doctor and pharmacist if any allergies are present to medications or any of the components found in Abacavir tablets or solutions. It's advisable to request a list of the ingredients from the pharmacist.

• Provide the doctor and pharmacist with a comprehensive list of all the prescription and nonprescription medications and other medications used to treat HIV. The doctor may need to adjust the medication dosage or monitor for potential side effects.

• Inform the doctor if there is the presence of any other health condition such as depression, diabetes, high blood pressure, high cholesterol, or liver or heart disease.

• Notify the doctor if pregnant, planning to become pregnant, or currently breastfeeding.

• Consult with the doctor about the safe use of alcohol while taking this medication.

• Inform the doctor that while taking HIV treatment medications, the immune system may strengthen and begin to combat infections already present in the body, including pneumonia, herpes virus, tuberculosis, hepatitis, or fungal infection.

Starting Abacavir Sulfate

Before Starting Abacavir sulfate:

When considering the use of any medication, it is important to weigh the potential risks against the benefits. The consulting doctor will help to make an informed decision about whether or not this medicine is right for the patient.

How to Take Abacavir Sulfate?

The medication can only be obtained with a valid prescription from a licensed healthcare provider. Abacavir sulfate is available in two forms:

• Tablets.

• Solution.

Abacavir is administered orally, either as a tablet or a solution. It is generally taken once or twice a day, with or without food, at almost the same time every day. To obtain optimal results, take abacavir precisely as directed by the doctor, neither more nor less, and do not take it more frequently than prescribed.

Abacavir does not cure HIV infection but aids in managing it. Even after feeling well, continue taking Abacavir. Do not stop taking the medication without consulting the doctor. If the medication is discontinued or missed doses, the condition may become more difficult to treat, or the patient may experience an allergic reaction when resuming the medication.

Things to Do After Starting Abacavir Sulfate:

• After starting Abacavir sulfate, it is important to take the medication as prescribed by the doctor and at the same time every day.

• Inform the doctor prior about any allergies to medications or any of the components found in Abacavir tablets or solution.

• Avoid taking the medication without the doctor’s permission, as doing such can lead to more difficult conditions to treat or an allergic reaction when restarting the medication.

Look Out for the Side Effects:

Abacavir has the potential to cause side effects. In case of any of the following symptoms, which may persist or worsen, immediately inform the doctor:

• Headache.

• Depression.

• Anxiety.

• Difficulty sleeping.

• Blisters or peeling skin.

• Hives.

• Itching.

• Difficulty swallowing or breathing.

• Excessive tiredness, weakness, dizziness, or lightheadedness.

• Fast or irregular heartbeat.

• Muscle pain.

• Stomach pain accompanied by nausea and vomiting.

• Shortness of breath or breathing difficulties.

• Flu-like symptoms, such as fever, chills, or cough.

• Feeling cold, particularly in the arms or legs.

• Light-colored bowel movements.

• Yellowing of the skin or eyes.

• Loss of appetite.

• Unusual bleeding or bruising.

• Dark yellow or brown urine.

• Pain in the upper right part of the stomach.

Abacavir may also cause other side effects, which should be discussed with the doctor.

For Doctors

Indication:

Abacavir is used in combination with other antiretroviral agents for the treatment of HIV-1 infection. It is also available in combination with Dolutegravir and Lamivudine for the treatment of HIV-1 in adult and pediatric patients weighing ≥10 kg.

Pharmacology:

Mechanism of Action: Abacavir is a synthetic nucleoside analog and antiviral agent that belongs to the carbocyclic class. It is converted into its active metabolite, Carbovir triphosphate, by cellular enzymes after entering the body. Carbovir triphosphate acts as an analog of deoxyguanosine-5'-triphosphate (dGTP) and competes with it to inhibit the activity of HIV-1 reverse transcriptase (RT). It also inhibits viral DNA growth by getting incorporated into viral DNA and terminating its elongation due to the lack of a 3'-OH group, which is essential for forming the 5′ to 3′ phosphodiester linkage.

Pharmacodynamics: Upon administration, Abacavir is converted into active metabolites that compete with viral DNA for incorporation. The metabolites act by inhibiting the HIV reverse transcriptase enzyme in a competitive manner and function as a chain terminator of DNA synthesis. The concentration of drug required to inhibit viral replication by 50 percent (EC50) ranges from 3.7 to 5.8 μM (1 μM = 0.28 mcg/mL) and 0.07 to 1.0 μM against HIV-1 IIIB and HIV-1BaL, respectively, and was found to be 0.26 ± 0.18 μM against eight clinical isolates. Abacavir demonstrates the non-nucleoside reverse transcriptase inhibitor (NNRTI) when used in combination with Nevirapine, the nucleoside reverses transcriptase inhibitor (NRTI) Zidovudine and the protease inhibitor (PI) Amprenavir. Additionally, abacavir exhibits additive activity when used in combination with other NRTIs including Didanosine, Emtricitabine, Lamivudine, Stavudine, Tenofovir, and Zalcitabine.

Absorption: The drug is rapidly and extensively absorbed when taken orally.

The bioavailability is 83%. The peak plasma concentration is 3 mcg/mL (300 mg) and 4.26 mcg/mL (600 mg). The area under the curve (AUC) is 6.02 mcg·h/mL (300 mg) and 11.95 mcg·h/mL (600 mg).

Metabolism and Elimination: Abacavir sulfate is metabolized by alcohol dehydrogenase and glucuronyl transferase. Around 82% of the administered dose is eliminated through urine as ABC metabolites. In individuals with hepatic insufficiency, dosage adjustment is advised.

Warnings and Precautions:

• Regular visits to the doctor are crucial to ensure that the medication is working effectively. The doctor may perform blood tests to check for any adverse effects.

• Do not use this medicine if a person is already taking other medicines that contain Abacavir.

• Severe allergic reactions may occur in some patients, usually within six weeks of starting the medication. These reactions can lead to low blood pressure and even death if left untreated.

• In case of sudden fever, skin rash, diarrhea, nausea, stomach pain, vomiting, unusual tiredness or illness, cough, trouble breathing, or sore throat, contact the doctor immediately.

• A warning card will be given to the patient that describes the symptoms of severe allergic reactions caused by Abacavir and how to manage them.

• Do not stop using the medication unless instructed by the doctor.

• In case of an allergic reaction to Abacavir, never use the medication again. Return any unused medication.

• Two rare but serious reactions to this medication are lactic acidosis and liver toxicity. Contact the doctor if a child experiences stomach discomfort or cramping, dark urine, decreased appetite, diarrhea, general discomfort, light-colored stools, muscle cramping or pain, nausea, weakness, trouble breathing, vomiting, or yellowing of the eyes or skin.

• This medication may cause excess body fat in some patients. Inform the doctor if a child notices changes in body shape.

• This medication may increase the risk of a heart attack, especially if they smoke or have heart disease, high blood pressure, high cholesterol, or high levels of fats in the blood. Contact the doctor immediately in case of chest pain, nausea, pain or discomfort in the arms, jaw, back, or neck, trouble breathing, sweating, or vomiting.

• This medication does not prevent the transmission of HIV during sexual activity. Use latex condoms and do not share needles, toothbrushes, or razor blades with others.

• Consult the doctor before taking any prescription or non-prescription medications, as well as herbal or vitamin supplements.

Dosage Strength and Forms:

For Adults -

The medication is available in the following dosage forms and strengths:

Oral solution at 20 mg/mL and tablet at 300 mg. It is indicated for the treatment of HIV infection in combination with other antiretroviral agents. For HIV infection, the usual dose is 300 mg taken by mouth every 12 hours, or 600 mg taken by mouth once daily.

For Children -

• To treat HIV infection in combination with other antiretroviral agents, this medication is available in an oral solution form with a strength of 20 mg/mL and a tablet form with a strength of 300 mg.

• For neonates and infants under 3 months of age, the safety and effectiveness of this medication have not been established.

• For those over 3 months of age, the recommended oral solution dosage is 8 mg/kg taken orally every 12 hours or 16 mg/kg/day. The daily dosage should not exceed 600 mg.

Dosage and Administration: For treating HIV infection, oral dosage forms such as solution or tablets are recommended. The dosage varies depending on the patient's age, weight, and health condition.

Adults are usually prescribed 300 milligrams (mg) of the medication twice per day or 600 mg once a day. Children aged three months or older are prescribed a dose based on their body weight, typically 8 milligrams (mg) per kilogram (kg) of body weight twice a day. The child's doctor may adjust the dose as necessary, but it usually does not exceed 600 mg per day.

For children weighing 14 kg or more who are capable of taking tablets, the dosage is usually 300 to 600 mg per day, taken once daily. Children under three months old should only use the medication under the guidance and dosage instructions of their doctor.

Considerations for Administration:

Dosage adjustments are not needed in renal impairment patients. However, for patients with mild hepatic impairment (Child-Pugh A), the dose should be reduced to 200 mg taken by mouth every 12 hours, using the oral solution.

Contraindications:

Abacavir is contraindicated in patients who have had a hypersensitivity reaction to Abacavir, which may include symptoms such as fever, skin rash, nausea, vomiting, diarrhea, abdominal pain, malaise, fatigue, myalgia, and respiratory symptoms. Patients who have a known hypersensitivity to any component of the product should not use abacavir. Additionally, Abacavir should not be used in patients who have the HLA-B*5701 allele, as this has been associated with a higher risk of hypersensitivity reactions to Abacavir.

Drug Interactions:

To avoid potential drug interactions, it is essential to inform the healthcare professional about all medications, including prescription and over-the-counter drugs. Although some medications should not be used together at all, in other cases, it may be necessary to use two different medicines together, and the doctor may need to adjust the dose or take other precautions.

The following interactions have been identified as significant but may not include all possible interactions:

• The doctor may not recommend using this medicine with Cabotegravir, Orlistat, Ribavirin, or Tacrolimus, but in some cases, both drugs may be prescribed together, and the doctor may adjust the dose or frequency of use.

• Using this medicine with Methadone or Tipranavir may increase the risk of certain side effects. However, both drugs may be necessary for treatment, and the doctor may adjust the dose or frequency of use.

Other Interactions:

Some medications should not be taken with specific types of food or at certain times when eating. Alcohol or tobacco use can also cause interactions with certain medications. It is important to talk to the healthcare provider about the use of the medication in relation to food, alcohol, or tobacco.

Other Specifications:

Abacavir Sulfate In Pediatrics:

The safety and effectiveness of abacavir in children under 3 months of age have not been established as no appropriate studies have been conducted.

Abacavir Sulfate in Geriatric Patients:

Although no geriatric-specific issues have been identified with Abacavir use, elderly patients may have age-related heart, liver, or kidney problems that may require careful monitoring and dosage adjustments.

Breastfeeding and Abacavir Sulfate:

There is a lack of adequate research on the potential risks to infants when using Abacavir during breastfeeding. Before taking this medication while breastfeeding, consider the possible risks and benefits.

Pregnancy and Abacavir Sulfate:

Abacavir sulfate is generally safe to use during pregnancy when the benefits outweigh the risks. However, it is mandatory to discuss any medication use during pregnancy with the healthcare provider. The U.S. Food and Drug Administration (FDA) categorizes abacavir sulfate as pregnancy category C, which means that animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in humans. Therefore, the medication should only be used during pregnancy if the potential benefits outweigh the potential risks to the fetus.