Reviewed by: HU Medical Review Board | Last reviewed: March 2023

Epzicom is a combination medication that contains abacavir and lamivudine. It is used with other antiretroviral agents as a part of antiretroviral therapy (ART) for people with HIV-1 (including children) who are at least 55 pounds (25 kilograms).

Although Epzicom is not a cure for HIV, when taken as directed, it allows for the virus to be suppressed. This prevents further transmission of HIV. It also allows an individual’s immune system to improve by increasing CD4 cell counts and decreasing the amount of active virus in the blood (viral load). CD4 cells are white blood cells that help trigger the immune system to fight infection.

What are the ingredients in Epzicom?

The main ingredients in Epzicom are abacavir and lamivudine. Both ingredients are nucleoside reverse transcriptase inhibitors (NRTIs).

How does Epzicom work?

Epzicom is a combination of two NRTI medications. NRTIs stop the reverse transcription step of the HIV life cycle. Normally, HIV uses its reverse transcriptase enzyme to build a strand of DNA from its original RNA form. In order to do this, it uses genetic building blocks called nucleosides that come from the host cell. These nucleosides are strung together one at a time, like beads on a string, to create the final DNA product.

NRTIs act as nucleoside mimics that stop the DNA-building process. NRTIs look like normal nucleosides, except they’re missing a special chemical group on one side. Without this group, the reverse transcriptase enzyme is unable to attach more nucleosides to the chain after them. This prevents the full string of DNA from being formed, preventing HIV RNA from making it all the way through the reverse transcription process and into host DNA for further replication.

What are the possible side effects?

As with any medication, there are several very rare but serious risks that need to be considered before taking Epzicom. Your healthcare provider can help determine what issues you may be at risk for and help determine what treatment options are the safest for you. It’s also important to remember that the risk of one or more of these issues occurring is low, and the benefits of treating the virus often greatly outweigh the risks.

The most common side effects of Epzicom include, but are not limited to:

  • Nausea
  • Dizziness
  • Tiredness
  • Depression
  • Headache
  • Diarrhea
  • Fever
  • Rash
  • Trouble sleeping

These are not all the possible side effects of Epzicom. Talk to your doctor about what to expect when taking Epzicom. You also should call your doctor if you have any changes that concern you when taking Epzicom.

Things to note about Epzicom

Epzicom has a boxed warning, the strictest warning from the US Food and Drug Administration (FDA). It has this warning because of the possibility of serious side effects as described below.

One of the active ingredients in Epzicom, abacavir, can cause severe allergic reactions in certain individuals. Although this is very rare, it is especially true for individuals with a gene mutation called HLA-B*5701. A blood test can be used to determine if someone has this mutation before starting the medication. An individual may be having an allergic reaction if they have a symptom from two or more of the following categories:

  • Fever
  • Rash
  • Abdominal pain, diarrhea, nausea, vomiting
  • Extreme tiredness, achiness, or a feeling of generally being ill
  • Sore throat, cough, shortness of breath

If you have, or think you may have, an allergic reaction to Epzicom, seek medical attention immediately and never restart Epzicom or another abacavir-containing product, as serious events including death may occur. If you stop Epzicom for any reason, tell your healthcare provider before starting the medication again.

Several other rare but serious side effects of Epzicom include liver issues and an increase of lactic acid in the blood (lactic acidosis). Signs of liver issues include, but are not limited to:

  • Dark-colored urine
  • Loss of appetite
  • Nausea
  • Yellowing of the whites of the eyes or skin
  • Light-colored bowel movements
  • Pain or tenderness on the right side of your stomach

Signs of lactic acidosis include, but are not limited to:

  • Trouble breathing
  • Feeling cold, especially in the limbs
  • Dizziness or lightheadedness
  • Feeling tired or weak
  • Muscle pain
  • Nausea and vomiting
  • Irregular or fast heartbeat

Although rare, Epzicom may also increase an individual’s risk of having a heart attack. It is important to tell your healthcare provider if you have any heart issues or have had heart issues in the past. If you have hepatitis B virus and start taking Epzicom, your hepatitis B may get worse. Your doctor will need to closely monitor your liver function if you have both HIV and hepatitis B.

Before starting Epzicom, tell your doctor if you:

  • Have or previously had hepatitis B virus
  • Have or previously had hepatitis C virus
  • Have a history of liver, heart, or kidney problems
  • Have a history of high blood pressure (hypertension), high cholesterol, or diabetes
  • Are a smoker
  • Drink alcohol or take medicines with alcohol in them
  • Are pregnant or planning to become pregnant
  • Are breastfeeding or planning to breastfeed
  • Are taking any over-the-counter vitamins, supplements, medicines, or herbal remedies
  • Are on any other medications or are about to start any other medications, including hormonal birth control, medications for hepatitis viruses, or methadone

People who are taking certain opioids for pain management may need to increase their opioid dose while taking Epzicom. Epzicom is not recommended for people with reduced or compromised kidney function. Risk factors such as diabetes, hypertension, and high cholesterol need to be managed in order to reduce the risk of myocardial infarction.

Epzicom may cause a condition called IRIS (immune reconstitution inflammatory syndrome). IRIS occurs when an individual’s immune system gets stronger after being weak and responds aggressively to previously hidden infections. This heightened response may make the person fighting the infection feel worse. Alert your healthcare provider immediately if you begin to have new symptoms after taking Epzicom.

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