Ziagen

•  See package insert for more complete information on potential side effects and interactions.

The length of this section is meant to be informative, not scary. The most common side effects with an incidence greater than 10% were nausea, headache, malaise (general ill feeling), fatigue, vomiting, and dreams/sleep disorders. In pediatric patients, the more common side effects were fever and/or chills, nausea and vomiting, skin rashes, and ear/nose/throat infections.

Approximately 8% of people who took abacavir in clinical trials (where screening for HLA-B*5701, a genetic marker associated with abacavir hypersensitivity, was not performed) experienced hypersensitivity reaction (HSR), an allergic-like reaction. To minimize the risk for HSR, a blood test for HLA-B*5701 should be done prior to starting an HIV regimen containing abacavir to identify patients at higher risk for this reaction. This test is covered by most insurance and also by LabCorp/ViiV (go to viivconnect.com). If the HLA-B*5701 test is positive, you are at an increased risk for HSR and you should not take abacavir. An allergy to it should be entered in your medical record. A negative HLA-B*5701 test does not mean you won’t have HSR, but the risk is very low (1% from clinical studies). Symptoms of HSR usually include some combination of the following: fever, skin rash, malaise (general ill feeling), severe nausea, headache, muscle ache, chills, diarrhea, vomiting, abdominal pain, respiratory symptoms (cough, difficulty breathing, sore throat), and/or joint pain. Symptoms are listed on the patient information sheet and warning card that you receive each time you fill your prescription. You should keep the warning card with you. HSR might be confused with flu, but symptoms of HSR usually worsen, very slowly, and with every dose.

People who think they are experiencing HSR must be evaluated by an experienced HIV provider right away before they stop taking abacavir. Do not use a skin patch test to confirm HSR. Symptoms usually resolve after permanent discontinuation. If you develop HSR, abacavir should be stopped and you can never take abacavir or any product containing abacavir (Epzicom, Trizivir, Ziagen, or Triumeq) again (starting again is called rechallenging). Rechallenging can cause a rare life-threatening reaction. This does not apply to a missed dose when there is no HSR, but talk with your healthcare provider and watch for symptoms if you’ve stopped the drug for a few days, preferably under the observation of others who can call for medical help if you develop symptoms. An HSR can technically occur at any time, regardless of how long you have been taking the medication, however, it is much more likely to occur when you start (or re-start) the medication (90% occur within the first 6 weeks of treatment).

Some large observational studies suggest abacavir may increase the risk of cardiovascular events, including myocardial infarction (MI, or heart attack), in people with risk factors (such as older age, smoking, diabetes, high blood pressure, high cholesterol, family history of heart disease, and drug use), especially within the first 6 months of therapy. However, other studies, including a large meta-analysis, have shown no increase in cardiovascular risk. To date, no consensus has been reached on the association of abacavir with cardiac risk or a possible mechanism for the association. People who are at high risk for heart disease should discuss risks with their provider and they should be monitored more closely.

Alcohol can increase abacavir levels and therefore can increase the possibility of side effects. Tell your provider or pharmacist about all medications, herbals, and supplements you are taking or thinking of taking, prescribed or not, as there are other drug interactions which are not listed here.

The ACTG A5202 study found that abacavir/lamivudine (Epzicom) was inferior to tenofovir/emtricitabine (Truvada) in getting people undetectable when their pre-treatment viral load was over 100,000 copies/mL. However, when combined with Tivicay (dolutegravir), Epzicom performed just as well as Truvada in people with high viral loads (over 100,000 copies/mL). Hence, Triumeq is the only abacavir-containing regimen recommended by DHHS as initial therapy for most HLA-B*5701 negative people. It is recommended that people with symptoms of acute respiratory disease consider HSR even if another diagnosis such as pneumonia, bronchitis, or flu is possible. But again, a simple test reveals whether you are at high risk for the allergic reaction. FDA researchers reported finding a mechanism for autoimmune drug reactions, including abacavir HSR, and hope it helps improve drug safety in the future. Ziagen as part of the combination tablet Epzicom is recommended by DHHS as one of the preferred NRTI combination components of an ART regimen during pregnancy.

See package insert for more complete information on potential side effects and interactions.

Dr. David Hardy says:

Ziagen was approved in 1998 as the fifth nuke at a time when HIV resistance to antiretrovirals and treatment failure was very common. It provided a new option for treatment at the time it was approved. From the beginning, this medication has had its challenges. As the drug was being studied in the late 1990s, a severe and possibly fatal allergic reaction (hypersensitivity) was discovered. Super elegant (cool) pharmacogenetic studies linked the occurrence of this side effect to a specific gene (HLA-B*5701). A simple blood or mouth swab can be used to detect this gene and determine if a PLWH can take the medication safely. Next, a European cohort study linked Ziagen to heart attacks, and a U.S. study showed it to be less potent than Viread. Despite these challenges, Ziagen has survived, a bit tattered, as a nuke still used today, almost exclusively in the STR Triumeq. A generic form of Ziagen has been available in the U.S. since 2012.

Activist Moisés Agosto-Rosario says:

Abacavir is a nucleoside reverse transcriptase inhibitor drug used for the treatment of HIV infection in combination with other HIV medicines. Serious side effects of abacavir include allergic reactions, a buildup of acid in the blood (lactic acidosis), and liver problems. If when taking abacavir you find yourself having an allergic reaction, stop the drug immediately and call your doctor. This hypersensitivity reaction can cause death. Your risk for this reaction is high if you have a specific gene variation, which can be determined by a blood test prescribed by a doctor.