Raltegravir: Uses, Indications, Side Effects, and Pharmacology

What Is Raltegravir?

Raltegravir is an antiretroviral (anti-HIV) medicine that belongs to a drug class called integrase strand transfer inhibitors (INSTIs), medicines that block the virus from inserting its genetic material into a person’s cells. It is used to treat HIV-1, the most common type of human immunodeficiency virus.

Raltegravir is approved for use both in combination with other antiretroviral medications and as part of PEP (post-exposure prophylaxis) treatment, for example, after needle stick injuries with unknown HIV status.

Raltegravir received its initial approval on October 12, 2007, from the Food and Drug Administration (FDA) for use in combination with other antiretroviral medications.

Drug group:

Raltegravir is a drug of the class integrase strand transfer inhibitors (INSTIs), which also includes medications like Elvitegravir, Dolutegravir, and Bictegravir.

Available doses and dosage forms:

• Tablets: These are regular pills with 400 mg of medicine, usually used for adults.

• Chewable tablets: These are small 25 mg tablets that you can chew, made for children or people who can’t swallow big pills.

• Oral suspension: This is a liquid form with 100 mg of medicine in 1 mL, mostly for kids or anyone who has trouble swallowing tablets.

For Patients

How Does Raltegravir Work?

Here’s how Raltegravir works:

• Attachment and fusion: HIV enters the body’s CD4 cells (immune cell that helps fight infections) by sticking to receptors on the cell surface. After attaching, the virus blends with the cell membrane and releases its genetic material, called RNA (ribonucleic acid), into the cell.

• Reverse transcription: Once inside, the virus changes its RNA into DNA (deoxyribonucleic acid) using a process called reverse transcription. This new viral DNA then moves into the cell’s nucleus (the cell’s control center).

• Integrase enzyme: For the virus to make more copies of itself, the viral DNA has to join with the cell’s DNA. The integrase enzyme (a protein that helps the virus attach its DNA to our DNA) does this job.

• Integration inhibition: Raltegravir blocks the integrase enzyme from working. It attaches to the active site (the working part) of integrase and stops the viral DNA from being inserted into the cell’s DNA. When this step is blocked, the virus cannot multiply properly, which helps control the infection. Thus, Raltegravir for HIV PEP treatment after potential exposures is an effective option to help prevent HIV infection.

What Is the Dosage of Raltegravir?

For adults and adolescents:

• The usual dose of Raltegravir for adults and teenagers is 400 mg, taken by mouth two times a day.

• It comes as a 400 mg tablet that you swallow.

For pediatric patients:

• The dose for children depends on their weight and age.

• Children usually need a smaller dose than adults.

• Raltegravir comes as a 25 mg chewable tablet or a liquid (oral suspension with 100 mg in 1 mL) for kids who have trouble swallowing regular tablets.

How Effective Is Raltegravir?

• Studies have shown that Raltegravir works well to stop HIV from making more copies of itself.

• It helps lower the viral load (the amount of HIV in the blood).

• Raltegravir is used along with other HIV medicines as part of combination antiretroviral therapy (ART).

• It helps keep HIV levels very low, which is called viral suppression.

• Viral suppression improves health and quality of life.

• It also helps prevent HIV from getting worse and reduces the chance of passing the virus to other people.

What Are the Things to Inform the Doctor Before Taking the Drug?

Before taking Raltegravir, make sure to tell your doctor:

• Your health history: Let them know if you have any long-term illnesses like liver or kidney problems, diabetes, or any mental health issues.

• All medicines you use: Tell your doctor about all prescription medicines, over-the-counter drugs, vitamins, and herbal products you take. This helps avoid harmful drug interactions.

• Any allergies: Especially if you have ever had an allergic reaction to a medicine.

• Pregnancy or breastfeeding: If you are pregnant, planning to get pregnant, or breastfeeding, the doctor will explain the risks and benefits.

• Liver and kidney issues: Because Raltegravir is processed in the liver and removed through the kidneys, your doctor may need to adjust the dose.

• Recent medical treatments: Share if you’ve had any surgeries, hospital visits, or ongoing medical procedures.

• Past HIV treatment: Let them know if you are newly diagnosed or if you’ve taken HIV medicines before.

• Lifestyle habits: Be honest about alcohol use, smoking, drug use, or sexual practices. This helps the doctor choose the best treatment plan for you.

• Birth control: If you’re sexually active and able to get pregnant, talk about safe contraception, as some medicines can affect birth control.

• Past reactions to medicines: Tell the doctor if you’ve had side effects or bad reactions to other medicines in the past.

How Is Raltegravir Administered?

Common ways to take Raltegravir:

• Tablets: These are regular pills you swallow with water. They usually come in a 400 mg strength and are used by people who can take pills easily.

• Chewable tablets: These are made for people who have trouble swallowing pills. You can chew or crush them before taking. They usually come in smaller strengths, like 25 mg, and are often used for children.

• Oral suspension: This is a liquid form of the medicine. It’s helpful for kids or anyone who can’t swallow tablets. A measuring device is included so the dose is correct. The liquid usually contains 100 mg of medicine in 1 mL.

What Are the Side Effects of Raltegravir?

Common side effects:

• Nausea (feeling like you want to vomit).

• Diarrhea (loose or watery stools).

• Headache.

• Fatigue (feeling very tired).

• Insomnia (difficulty sleeping).

• Rash.

Less common side effects:

• Changes in liver function tests (results that show the liver may not be working normally).

• High levels of creatine kinase (an enzyme in muscles high levels can mean muscle stress or damage).

• Muscle pain or weakness.

• Increased blood sugar.

• Changes in body fat distribution (fat moving to different parts of the body, like the belly or back).

Serious side effects:

• Severe skin reactions.

• Liver problems, including hepatotoxicity (serious liver damage).

• Allergic reactions (swelling, itching, or trouble breathing).

• Immune reconstitution syndrome (when the immune system gets stronger and suddenly reacts to infections already in the body).

Dietary considerations:

Here are a few dietary guidelines to consider:

• Try to take Raltegravir at the same time every day, preferably with food. This can help your body absorb the medicine better and may reduce stomach problems like nausea or diarrhea.

• Ask your doctor about eating grapefruit or drinking grapefruit juice. It usually doesn’t affect Raltegravir, but it’s still good to check.

• Eat a balanced diet with fruits, vegetables, whole grains, and protein to support your immune system and keep your energy levels up.

• Drink plenty of water during the day to stay hydrated and help your body handle any side effects.

• Talk to your doctor before taking vitamins or mineral supplements. They can help you pick the right ones if you need them.

• Be honest about alcohol or recreational drug use. Some substances can interact with your medicine or affect your overall health.

Overdose:

If you think someone has taken too much Raltegravir, get help right away. An overdose can be serious.

• Call emergency services or go to the nearest hospital if you notice any worrying symptoms.

• Watch for signs like very bad nausea, vomiting, dizziness, confusion, or anything that feels unusual or severe.

• At the hospital, doctors will check you, give you the right treatment, and monitor your health to make sure you’re safe.

Storage:

• Keep your Raltegravir tablets at room temperature (about 68 to 77 degrees Fahrenheit or 20 to 25 degrees Celsius) and away from direct light, heat, or moisture.

• If you have Raltegravir oral suspension (liquid), follow the storage instructions on the label carefully. Some liquid forms need to be kept in the fridge, and there may be limits on how long you can use them after opening or mixing.

• Keep all Raltegravir medicines out of reach of children and pets to avoid accidents.

• Do not store medicine in the bathroom, because heat and humidity can affect it.

• Throw away any leftover or expired medicine safely, following local rules. Many pharmacies have programs to help with this.

• When traveling, keep Raltegravir in its original packaging. This helps protect the medicine and makes it easy for doctors to identify it if needed.

For Doctors

Pharmacodynamics:

The pharmacodynamics of Raltegravir include the following key points:

• Inhibition of integrase: Raltegravir is classified as an integrase strand transfer inhibitor (INSTI). Its primary mechanism of action is to inhibit the integrase enzyme of the human immunodeficiency virus (HIV). Integrase inserts the viral DNA into the host cell's DNA during viral replication.

• Preventing integration: By binding to the active site of integrase, Raltegravir prevents the enzyme from effectively integrating the viral DNA into the host cell's DNA.

• Viral replication suppression: Raltegravir inhibits integrase, decreasing viral replication. The virus cannot effectively integrate its genetic material into the host cell DNA, so it cannot produce new viral particles.

• Immune system recovery: By reducing the viral load, Raltegravir helps support the immune system's recovery by increasing the CD4 T-cell counts, helping the immune system regain strength and function.

• Reduction of viral load: By suppressing viral replication, Raltegravir helps reduce the viral load in the bloodstream.

Mechanism:

In treating HIV-1, Raltegravir works as an integrase strand transfer inhibitor (INSTI). It blocks an enzyme called integrase, which HIV needs to insert its genetic material into your cells. By stopping this step, Raltegravir helps prevent the virus from making more copies of itself.

Pharmacokinetics:

Pharmacokinetics is how the body absorbs, distributes, breaks down, and removes a medicine. Understanding this helps doctors choose the right dose of Raltegravir to make sure it works effectively.

Here are the key points about Raltegravir’s pharmacokinetics:

• Absorption: After oral administration, Raltegravir is well absorbed from the gastrointestinal tract. The rate and extent of absorption are influenced by factors such as food intake. Taking Raltegravir with food, especially a meal containing some fat, can increase its bioavailability. However, It can also be taken without regard to meals.

• Distribution: Raltegravir is distributed throughout the body, including various tissues and cells. It crosses the blood-brain barrier to some extent, which is important for suppressing HIV replication in the central nervous system.

• Metabolism: Raltegravir is mostly processed in the liver through a process called glucuronidation (the drug is combined with a substance called glucuronic acid to make it inactive). It is not much affected by the liver’s usual drug-processing enzymes, which means it has a lower chance of interacting with other medicines.

• Elimination: Raltegravir and its inactive forms leave the body mainly through the kidneys, with a small amount in the stool. If your kidneys are not working well, your doctor may need to adjust your dose.

• Half-life: Raltegravir stays in the body for about nine hours in adults, which means half of the medicine is gone after nine hours. To keep the medicine working properly, it is usually taken twice a day.

Toxicity:

Generally, Raltegravir is well-tolerated when used according to prescribed HIV treatment regimens. However, like all medications, it has the potential to produce toxic effects. The toxicities from this could be classified as such; hence, knowing the possible toxicities of Raltegravir calls for urgent reporting of suspected symptoms to the provider.

• Liver function: Raltegravir can affect liver function. Elevated liver enzymes (transaminases) may occur, and in rare cases, severe hepatotoxicity (liver toxicity).

• Gastrointestinal issues: Common side effects include nausea, diarrhea, and abdominal discomfort. Severe or persistent gastrointestinal symptoms should be reported to the healthcare provider.

• Immune reconstitution syndrome: As the immune system improves with antiretroviral treatment, there is a risk of immune reconstitution syndrome (IRIS). The immune response to pre-existing infections worsens symptoms. IRIS may present as inflammatory reactions, swelling, or other complications.

• Skin reactions: These are severe skin rashes or allergic reactions that require immediate medical attention.

• Creatine kinase levels: Raltegravir may lead to elevated creatine kinase levels (an enzyme in muscle tissue). While this is generally not harmful, very high levels could indicate muscle-related issues.

What Are the Contraindications For Using Raltegravir?

Contraindications include:

• Allergy warning: Do not take Raltegravir if you are allergic to it.

• Avoid with Rifampin: Do not use Raltegravir with Rifampin, as this can make Raltegravir less effective.

• Liver problems: Use Raltegravir carefully if you have severe liver issues.

Warnings and precautions:

• Allergic reactions: Some people may have hypersensitivity reactions. If you notice a severe rash, blisters, or other allergy signs, seek medical help right away.

• Liver function: Raltegravir can affect your liver. Doctors may check your liver enzymes regularly, especially early in treatment. Severe liver damage is rare but possible. Be careful if you already have liver problems.

• Immune reconstitution syndrome (IRIS): When starting HIV treatment, your immune system may suddenly react to hidden infections, causing inflammation or symptoms.

• Risk of resistance: If the virus is not fully suppressed, HIV can become resistant to Raltegravir. It should always be used with other HIV medicines to prevent this.

• For children: Safety and effectiveness can be different from adults. Doses are based on age and weight.

• Pregnancy and breastfeeding: Safety is not fully known. Talk to your doctor before using it.

• For older adults: Limited information is available. Doctors may need to consider other health conditions, age changes, and possible drug interactions.