Retrovir
Common Name: zidovudine or AZT
Brand Name: Retrovir
Class: nucleoside analogs (also called nucleoside reverse transcriptase inhibitors, NRTIs, or nukes)
Standard dose: One 300 mg tablet twice a day (12 hours apart); two 100 mg capsules three times a day also available, with or without food, and no food restrictions. Clear, strawberry-flavored liquid available for infants four weeks of age and up; dose is weight-based. Take missed dose as soon as possible, unless it is almost time for your next dose. Do not double up on your next dose. Generic is available.
AWP: $505.31 (generic $365.09) / month for 300 mg tablets, $67.37 (generic $56.42) for 240 ml syrup
Manufacturer contact: ViiV Healthcare, 1 (877) 844-8872
Potential side effects and toxicity: May include headaches, fever, chills, muscle soreness, fatigue, nausea, and fingernail discoloration. Zidovudine (AZT) has been associated with alteration of various cells in the blood through bone marrow suppression, resulting in anemia (low red blood cell counts) and/or neutropenia (low white blood cell counts), particularly during the first three months of therapy in people with advanced HIV. Potential exists for severe anemia requiring blood transfusion, erythropoietin injections, or hospitalization when used on its own or in combination with hydroxyurea. Rare but potentially serious toxicity with all NRTIs: enlarged fatty liver (hepatomegaly with steatosis) and lactic acidosis (accumulation of lactate in the blood and abnormal acid-base balance). Lactic acidosis may cause persistent fatigue, abdominal pain or distension, nausea/vomiting, difficulty breathing or shortness of breath, and enlarged, fatty liver.
Potential drug interactions: Biaxin and rifampin (under various brand names) may decrease zidovudine blood levels. Benemid (probenecid), Dilantin (phenytoin), and Depakote (valproic acid) may increase zidovudine blood levels and decrease zidovudine clearance, but no dosing adjustments are recommended. Zidovudine and Zerit should not be used together due to evidence that one limits the other’s effectiveness. Also, bone marrow suppression should be monitored with use of Cytovene (ganciclovir), Valcyte, amphotericin B, pentamidine, dapsone, flucytosine, sulfadiazine, interferon-alpha, ribavirin (Rebetol), and with cancer treatments such as hydroxyurea and doxorubicin. Ribavirin and zidovudine may cancel each other out, so this combination should be monitored closely. New Procrit or Epogen warning: if hemoglobin target is above manufacturer’s recommendation (12 g/dL), the risk for serious and life-threatening cardiovascular complications significantly increases. For zidovudine 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, increases in blood pressure, dizziness or loss of consciousness, extreme tiredness, or blood clots in hemodialysis vascular access ports. Do not take with Combivir or Trizivir, since zidovudine is already in these medications.
Tips: The not-so-good news for people adding zidovudine: the fatigue and the potential anemia. You can start taking erythropoietin (Procrit or Epogen) for some anemias, but that’s adding an expensive weekly injectable. Some doctors would prefer switching out the zidovudine for another drug. Zidovudine/AZT is associated with lipoatrophy (fat loss of the arms, legs, face, and/or buttocks—sometimes called “AZT butt”). The lipoatrophy could be irreversible or take a long time to rebuild. Taking with food may minimize upset stomach. Please see package insert for more complete potential side effects and interactions.
Doctor
Retrovir (zidovudine, known to most as AZT, with a generic form available in the U.S.) was the first antiretroviral developed and has had a significant impact on the course of HIV infection. Historically, AZT development has served as an example of a highly successful government and industry partnership to combat a lethal disease. AZT is now primarily used in the fixed dose combinations Combivir or Trizivir. Since the approval of other more convenient and safer antiretrovirals, the use of AZT in HAART therapy has decreased significantly. There is one time when AZT is still considered “preferred” which is for a pregnant woman during her pregnancy—this is the recommendation of guideline panels who have reviewed all of the amount of information that is available about this drug in that setting. —Cal Cohen, MD
Activist
The original, and much maligned, AZT continues to be a widely used and well tolerated drug for many—though it’s no longer included in the recommended regimens on the guidelines. Despite the potential anemia, fatigue, and lipoatrophy, its penetration into the central nervous system makes it very useful for those suffering from dementia and other cognitive problems. —Jeff Taylor
