Combivir

Nucleoside Reverse Transcriptase Inhibitor

Combo Drug

Common Name: zidovudine (AZT) and lamivudine (3TC)

Brand Name: Combivir

Class: fixed dose combination -- nucleoside analogs (also called nucleoside reverse transcriptase inhibitors, NRTIs or nukes)

Standard dose: One tablet (150 mg Epivir/3TC/lamivudine, 300 mg zidovudine/AZT/Retrovir), twice a day (12 hours apart), with 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: $921.44 / month
Manufacturer contact: GlaxoSmithKline,
www.combivir.com, 1 (888) 825-5249

AIDSInfo:
1 (800) HIV-0440 (448-0440), www.aidsinfo.nih.gov

Potential side effects and toxicity: See drug pages for Epivir (lamivudine, 3TC) and Retrovir (zidovudine, AZT) for more details. May be taken with food to decrease potential nausea associated with AZT.

Potential drug interactions: See the drugs contained in Combivir -- Epivir (lamivudine, 3TC), and Retrovir (zidovudine, AZT). Do not take zidovudine (Retrovir), Epivir, Epzicom, Trizivir, Emtriva, Truvada, or Atripla while taking Combivir, since all or part of these medications are already in Combivir or have equivalent medications. Rare but potentially fatal toxicity with all NRTIs: hepatomegaly with steatosis (enlarged, fatty liver) and lactic acidosis (accumulation of lactate in the blood and abnormal acid-base balance).

Tips: It is the combination of lamivudine, 3TC (Epivir) and zidovudine, AZT (Retrovir) into one pill; see the pages of those individual drugs for more information. Combivir has been shown in multiple clinical trials to be a potent regimen with either a protease inhibitor or an NNRTI. The AZT in Combivir can cause fatigue and anemia -- it isn't pretty in those at risk for developing anemias (see Retrovir). One head-to-head study against Truvada found greater toxicity with Combivir, due to anemia. See Retrovir. Procrit or Epogen warning: if hemoglobin target is above manufacturer's recommendation (12 g/dL), risk for serious and life-threatening cardiovascular complications significantly increases. For AZT patients, measure hemoglobin once a week after starting the anemia drugs until hemoglobin has stabilized. Notify health care provider if experiencing pain and/or swelling in the legs, worsening in shortness of breath, increase in blood pressure, dizziness or loss of consciousness, extreme tiredness, or blood clots in hemodialysis vascular access ports. Combivir brings with it one of the "T" drugs, or thymidine analogs (AZT and Zerit) -- some clinicians are avoiding those when possible because of their implication in lipoatrophy (thinning of the arms, legs, and face). The wasting of "AZT butt" could be irreversible or take a long time to rebuild. Please see package insert for more complete potential side effects and interactions.

Doctor

Combivir (combination AZT/3TC) was the first fixed dose combination antiretroviral therapy approved (1997) for HIV infection. It simplified and revolutionized treatment and quickly became the "gold standard" for HIV therapy. It made a significant impact on the lives of those infected with HIV at the time. Unlike other fixed dose combinations, Combivir was never approved for once-daily usage. The short half life of AZT in the cell necessitated twice-daily dosing (for efficacy). Among the advantages of this drug are the reduced number of pills and the potential positive effect of the 3TC mutation (M184V) on the efficacy of AZT. The disadvantages rest primarily with the major toxicities of AZT (see Retrovir). With the approval of other, better tolerated, once-daily fixed dose combinations, our use of this drug has decreased significantly. Approximately 5% of our clinic population is currently taking Combivir. The area of greatest usage is pregnancy. Most of the data for the reduction of mother-to-child transmission was done with AZT. From a global standpoint, and specifically in Uganda, Combivir is the most frequently used first-line agent (used more than AZT and/or 3TC separately) in HAART regimens. -- Frank M. Graziano, M.D., Ph.D.

Activist

Seemingly just when AZT's patent was about to expire, Burroughs-Wellcome (now GlaxoSmithKline) came along with the maverick of fixed dose combination therapy. Combivir reduced pill burden, the number of pills taken every day, simplifying HIV therapy and other dual fixed dose combinations would follow (Epzicom, Truvada); and eventually, triple fixed dose combinations (Trizivir, Atripla). What we learned from Combivir: Know what you're taking! Combivir still had the same side effects of its components, AZT and 3TC, but the new drug came along before HAART and many got caught in the "new and improved" trap. Many who swore they would never take AZT did so unwittingly. Though Combivir is safe, tolerable, and durable, it is a DHHS Guidelines Panel "alternative" dual-NRTI. Epivir/3TC has a mutation that has been linked to increased resistance to Retrovir/AZT; thus, the sum is not greater than its parts. -- Morris Jackson

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