abacavir sulfate and lamivudine
Class: fixed dose combination—nucleoside analogs (also called nucleoside reverse transcriptase inhibitors, NRTIs or nukes)
Standard dose: One tablet (600 mg Ziagen/abacavir sulfate and 300 mg Epivir /3TC/ lamivudine), once a day, no food restrictions (may be taken with or without food). Take missed dose as soon as possible, but do not double up on your next dose.
AWP: $906.85 / month
Manufacturer contact: GlaxoSmithKline,
www.epzicom.com, 1 (888) 825–5249
1 (800) HIV–0440 (448–0440), www.aidsinfo.nih.gov
Potential side effects and toxicity: The most common side effects of Epzicom are the same as the drugs contained in Epzicom: Epivir and Ziagen. See those pages for more information. Of note is the hypersensitivity reaction (HSR, an allergic-like reaction) warning on abacavir (Ziagen); see Ziagen. If treatment is stopped because of this serious reaction, you can never take Ziagen, Trizivir or Epzicom again (called “re-challenging”) because of life-threatening and in a few instances fatal reaction. (This does not apply to missed doses, when there’s no HSR, but watch for symptoms if you’ve stopped the drug for at least a few days). Symptoms usually, but not always, include some combination of sudden fever, muscle ache, severe nausea, vomiting or abdominal pain, severe tiredness, respiratory symptoms (cough, difficulty breathing and sore throat) and possibly mild rash. These symptoms are listed on the patient information sheet and warning card that you receive each time you fill your prescription. You should always keep the warning card with you. Hypersensitivity might be confused with flu during flu season, but remember that HSR worsens with every dose. A blood test for HLA-B*5701 can identify people at high risk for this reaction. See tips.
Potential drug interactions: See also the drugs contained in Epzicom, Epivir and Ziagen, for more information. Do not take Combivir, Epivir, Trizivir, Ziagen, Emtriva, Truvada, or Atripla while taking Epzicom, since all or part of these medications are already in Epzicom or have equivalent medications.
Tips: Remember, Epzicom is two drugs in one pill, so see the pages for those drugs, Epivir and Ziagen. Ziagen by itself is FDA approved for either once-a-day or twice-a-day dosing. The once-daily formula in Epzicom was found to have the same amount in the blood over 24 hours (bioequivalency) as Ziagen twice-a-day. Currently, U.S. HIV treatment guidelines recommend Truvada over Epzicom as a preferred agent for the NRTI component of a treatment regimen. Epzicom is not on the preferred list due to the risk of hypersensitivity reactions even though it has demonstrated potency when compared to Combivir. The Ziagen in Epzicom unfortunately has a hypersensitivity reaction (HSR) in about 8% of people taking it. Inexpensive screening, however, can now virtually eliminate HSR! Don’t be afraid of genetic testing—it’s only looking for one tiny part of your genes. Regardless of the results, it is important to monitor for the potential for this reaction. If HSR is suspected or cannot be ruled out, abacavir products should be discontinued. The test should never be used to diagnose HSR. Healthcare providers should visit www.hlab5701survey.com to learn more and get free tests. The incidence of HSR was the same between Epzicom and Ziagen twice-a-day (8% vs. 9%), but the incidence of severe reactions was higher with Epzicom (5% vs. 2%). Remember that the HSR cited may have been suspected, not definitely diagnosed. Check with your doctor if you have any side effects after taking this medicine—don’t just stop! Please see package insert for more complete potential side effects and interactions.
Epzicom is another great choice. Its main advantage over Truvada is the lack of any kidney toxicity; the disadvantage is the need to get a HLA-B*5701 test first, and then to have to read the “death card” the pharmacist gives you (see “Ziagen”). Studies comparing Truvada and Epzicom are in progress.—Joel Gallant, M.D.
Epzicom is another fixed dose combination created by GlaxoSmithKline. When Gilead launched Viread/tenofovir, it quickly began to outsell GSK’s Ziagen. Both are considered “second generation” drugs and are generally more potent than earlier nucleoside analogue drugs like AZT and ddI. Epzicom combines Ziagen with its earlier drug Epivir/3TC. It is generally considered more potent than GSK’s early combination drug Combivir and has the added advantage of once daily dosing. But like any fixed dose combination, Epzicom carries both the strengths and weaknesses of the individual drugs involved. The concern in this case is the Ziagen component, which has high potency but one relatively serious side effect issue. A small percentage of people who use Ziagen, whether alone or in Epzicom (or Trizivir), can suffer a potentially lethal allergic reaction. Physicians are generally knowledgeable in recognizing and handling the problem, but the risk of the problem is enough to discourage many people from trying any form of Ziagen. However, a genetic test is also available which can predict who is likely to have the problem. With the use of this modestly priced test, Epzicom becomes a valid alternative to its main competitor, Truvada from Gilead Sciences. Still, the mere awareness of the allergic reaction problem has limited the sales of Epzicom and Ziagen.—Martin Delaney