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HIV-1 infection: Treatment of HIV-1 infection in combination with at least two other antiretroviral agents.
Perinatal HIV-1 transmission: Prevention of perinatal HIV-1 transmission
Potentially life-threatening hypersensitivity to zidovudine or any component of the formulation
Canadian labeling: Additional contraindications (not in U.S. labeling): Neutrophil count <750/mm3 or hemoglobin <7.5 g/dL (4.65 mmol/L)
Zidovudine has been associated with hematologic toxicity, including neutropenia and severe anemia, particularly in patients with advanced HIV-1 disease.
Myopathy:Prolonged use of zidovudine has been associated with symptomatic myopathy.
Lactic acidosis/severe hepatomegaly:Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination, including with zidovudine and other antiretrovirals. Suspend treatment if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur.
Note: Patients should receive IV therapy only until oral therapy can be administered.
Prevention of maternal-fetal HIV transmission: Dose adjustment not required in pregnant women. Zidovudine should be administered by continuous IV infusion near delivery regardless of antepartum regimen or mode of delivery in women with HIV RNA >1,000 copies/mL or unknown HIV RNA status. If oral zidovudine was part of the antepartum regimen, discontinue during intrapartum IV infusion. Other antiretroviral agents should be continued orally. Zidovudine IV is not required in women receiving combination antiretroviral therapy who have HIV RNA <1,000 copies/mL near delivery and there are no concerns related to adherence with the regimen (HHS [perinatal] 2016).
IV (preferred route): During labor and delivery: Loading dose: 2 mg/kg followed by a continuous IV infusion of 1 mg/kg/hour until delivery. For scheduled cesarean delivery, begin IV zidovudine 3 hours before surgery. In cases of unscheduled cesarean delivery due to maternal and fetal indications, consider administering the loading dose then proceeding to delivery.
Oral (if IV not possible): Loading dose: 600 mg, then 400 mg every 3 hours (oral is not the preferred route of administration in the United States)
Treatment of HIV infection:
Oral:
US labeling: 300 mg twice daily
Canadian labeling: 300 mg twice daily or 200 mg 3 times daily
IV:
US labeling: 1 mg/kg/dose administered every 4 hours around-the-clock (5 to 6 doses daily)
Canadian labeling: 1 to 2 mg/kg/dose administered every 4 hours around-the-clock (6 doses daily)
Postexposure prophylaxis (off-label use): Oral: 300 mg twice daily or 200 mg 3 times daily in combination with lamivudine or emtricitabine. A third agent may be added for high-risk exposures. Therapy should be started within hours of exposure and continued for 4 weeks (CDC, 2005).
Refer to adult dosing.
Note: Patients should receive IV therapy only until oral therapy can be administered.
Prevention of perinatal HIV transmission (in neonates): Note: Start as soon as possible after birth, preferably within 6 to 12 hours of delivery. Continue dose from birth through 6 weeks of age (a 4-week course may be considered for full-term neonates if the mother received ART therapy during pregnancy consistent with viral suppression and there are no concerns related to adherence with the regimen). Use of a 6 week course of zidovudine in combination with nevirapine is recommended for infants at higher risk of HIV acquisition (eg, infants born to mothers with suboptimal viral suppression [>1,000 copies/mL] near delivery, only intrapartum therapy, or no therapy) (HHS [perinatal] 2016).
Oral:
Manufacturers labeling: Full-term infants: 2 mg/kg every 6 hours
Alternative dosing (HHS [perinatal] 2016):
Infants ≥35 weeks gestation at birth: 4 mg/kg/dose twice daily
Infants ≥30 weeks and <35 weeks gestation at birth: 2 mg/kg/dose every 12 hours; at 15 days of age, advance to 3 mg/kg/dose every 12 hours
Infants <30 weeks gestation at birth: 2 mg/kg/dose every 12 hours; at 4 weeks of age, advance to 3 mg/kg/dose every 12 hours
IV (infants unable to receive oral dosing):
Manufacturer 's labeling: 1.5 mg/kg/dose every 6 hours
Alternate dosing (HHS [perinatal] 2016):
Infants ≥35 weeks gestation at birth: 3 mg/kg/dose every 12 hours
Infants ≥30 weeks and <35 weeks gestation at birth: 1.5 mg/kg/dose every 12 hours; at 15 days of age, advance to 2.3 mg/kg/dose every 12 hours
Infants <30 weeks gestation at birth: 1.5 mg/kg/dose every 12 hours; at 4 weeks of age, advance to 2.3 mg/kg/dose every 12 hours
Treatment of HIV infection:
Infants, Children, and Adolescents 4 weeks to <18 years:
Oral: Dose should be calculated by body weight (in kg) or body surface area and should not exceed the recommended adult dose. Note: Doses calculated by body weight may not be the same as those calculated by body surface area.
Dosing based on body surface area: 240 mg/m2 twice daily (maximum: 300 mg twice daily) or 160 mg/m2/dose 3 times daily (maximum: 200 mg 3 times daily)
Dosing based on weight (Note: 3 times daily dose is approved but rarely used in clinical practice):
4 to <9 kg: 12 mg/kg/dose twice daily or 8 mg/kg/dose 3 times daily
≥9 to <30 kg: 9 mg/kg/dose twice daily or 6 mg/kg/dose 3 times daily
≥30 kg: 300 mg twice daily or 200 mg 3 times daily
Infants ≥3 months and Children (Canadian labeling): IV intermittent infusion: 120 mg/m2/dose every 6 hours
Adolescents ≥30 kg (Canadian labeling): IV intermittent infusion: 1 to 2 mg/kg/dose every 4 hours around-the-clock (6 doses daily)
CrCl ≥15 mL/minute: No dosage adjustment necessary.
CrCl <15 mL/minute
Oral:
Manufacturer 's labeling: 100 mg every 6 to 8 hours
Alternate dosing: 100 mg 3 times daily or 300 mg once daily (HHS [adult] 2015)
IV: 1 mg/kg every 6 to 8 hours
ESRD on intermittent hemodialysis (IHD) (administer dose after dialysis on dialysis days):
Oral:
Manufacturer 's labeling: 100 mg every 6 to 8 hours
Alternate dosing: 100 mg 3 times daily or 300 mg once daily (HHS [adult] 2015)
IV: 1 mg/kg every 6 to 8 hours
Peritoneal dialysis (PD):
Oral: 100 mg every 6 to 8 hours
IV: 1 mg/kg every 6 to 8 hours
Continuous renal replacement therapy (CRRT): No adjustment needed (Aronoff, 2007)
There are no specific dosage adjustments provided in the manufacturers labeling (has not been studied). However, adjustment may be necessary due to extensive hepatic metabolism.
Hazardous agent; use appropriate precautions for handling and disposal (NIOSH 2014 [group 2]).
Solution for injection should be removed from the vial and diluted with D5W to a concentration ≤4 mg/mL.
Oral: Administer around-the-clock to promote less variation in peak and trough serum levels; may be administered without regard to meals
IV: Avoid rapid infusion or bolus injection. Do not administer IM
US labeling:
Neonates: Infuse over 30 minutes
Adults: Infuse over 1 hour; in pregnant women, infuse loading dose over 1 hour followed by continuous infusion
Canadian labeling:
Neonates: Infuse over 30 minutes
Infants ≥3 months, Children, Adolescents, and Adults: Infuse over 1 hour; in pregnant women, infuse loading dose over 1 hour followed by continuous infusion
Hazardous agent; use appropriate precautions for handling and disposal (NIOSH 2014 [group 2]).
IV: Store undiluted vials at 15 � �C to 25 � �C (59 � �F to 77 � �F). Protect from light. When diluted in D5W, solution is physically and chemically stable for 24 hours at room temperature and 48 hours if refrigerated. Attempt to administer diluted solution within 8 hours if stored at room temperature or 24 hours if refrigerated to minimize potential for microbial-contaminated solutions (vials are single-use and do not contain preservative).
Tablets, capsules, syrup: Store at 15 � �C to 25 � �C (59 � �F to 77 � �F). Protect capsules from moisture.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Retrovir: 100 mg [contains soybean lecithin]
Generic: 100 mg
Solution, Intravenous [preservative free]:
Retrovir: 10 mg/mL (20 mL)
Syrup, Oral:
Retrovir: 50 mg/5 mL (240 mL) [contains sodium benzoate; strawberry flavor]
Generic: 50 mg/5 mL (240 mL)
Tablet, Oral:
Retrovir: 300 mg [DSC]
Generic: 300 mg
Stable in D5W, NS.
Incompatible with blood products and protein solutions.
Acyclovir-Valacyclovir: May enhance the CNS depressant effect of Zidovudine. Monitor therapy
Amodiaquine: Zidovudine may enhance the neutropenic effect of Amodiaquine. Avoid combination
BCG (Intravesical): Myelosuppressive Agents may diminish the therapeutic effect of BCG (Intravesical). Avoid combination
Clarithromycin: May enhance the myelosuppressive effect of Zidovudine. Clarithromycin may decrease the serum concentration of Zidovudine. Management: Monitor response to zidovudine closely when used with clarithromycin, and consider staggering zidovudine and clarithromycin doses when possible in order to minimize the potential for interaction. Consider therapy modification
CloZAPine: Myelosuppressive Agents may enhance the adverse/toxic effect of CloZAPine. Specifically, the risk for neutropenia may be increased. Monitor therapy
Deferiprone: Myelosuppressive Agents may enhance the neutropenic effect of Deferiprone. Avoid combination
Dexketoprofen: May enhance the adverse/toxic effect of Zidovudine. Monitor therapy
Dipyrone: May enhance the adverse/toxic effect of Myelosuppressive Agents. Specifically, the risk for agranulocytosis and pancytopenia may be increased Avoid combination
DOXOrubicin (Conventional): May enhance the adverse/toxic effect of Zidovudine. DOXOrubicin (Conventional) may diminish the therapeutic effect of Zidovudine. Consider therapy modification
DOXOrubicin (Liposomal): May enhance the adverse/toxic effect of Zidovudine. DOXOrubicin (Liposomal) may diminish the therapeutic effect of Zidovudine. Consider therapy modification
Fluconazole: May decrease the metabolism of Zidovudine. Monitor therapy
Ganciclovir-Valganciclovir: May enhance the adverse/toxic effect of Reverse Transcriptase Inhibitors (Nucleoside). Hematologic toxicity with zidovudine is of particular concern. Ganciclovir-Valganciclovir may increase the serum concentration of Reverse Transcriptase Inhibitors (Nucleoside). Management: Monitor patients receiving any of these combination closely for toxicity of the reverse transcriptase inhibitor. Avoid zidovudine. Intravitreal implants would not be affected. Consider therapy modification
Interferons: May enhance the adverse/toxic effect of Zidovudine. Interferons may decrease the metabolism of Zidovudine. Monitor therapy
Methadone: May increase the serum concentration of Zidovudine. Monitor therapy
Probenecid: May decrease the metabolism of Zidovudine. Monitor therapy
Protease Inhibitors: May decrease the serum concentration of Zidovudine. Monitor therapy
Raltegravir: May enhance the myopathic (rhabdomyolysis) effect of Zidovudine. Monitor therapy
Ribavirin (Oral Inhalation): Zidovudine may enhance the adverse/toxic effect of Ribavirin (Oral Inhalation). Specifically, the risk/severity of anemia may be increased. Management: Due to significantly increased risk of anemia, consider even closer monitoring for anemia than routinely recommended. Alternative therapies should be considered when clinically possible, particularly for patients with other risk factors. Consider therapy modification
Ribavirin (Systemic): Zidovudine may enhance the adverse/toxic effect of Ribavirin (Systemic). Specifically, the risk/severity of anemia may be increased. Management: Due to significantly increased risk of anemia, consider even closer monitoring for anemia than routinely recommended for ribavirin. Alternative therapies should be considered when clinically possible, particularly for patients with other risk factors. Consider therapy modification
Rifamycin Derivatives: May decrease the serum concentration of Zidovudine. Exceptions: Rifabutin. Monitor therapy
Stavudine: Zidovudine may diminish the therapeutic effect of Stavudine. Avoid combination
Tenoxicam: May enhance the adverse/toxic effect of Zidovudine. Monitor therapy
Teriflunomide: May increase the serum concentration of OAT3 Substrates. Monitor therapy
Valproate Products: May increase the serum concentration of Zidovudine. Monitor therapy
Monitor viral load (2 to 8 weeks after initiation/modification of therapy, and then every 3 to 6 months); CBC with differential (every 3 to 6 months); liver function tests (every 6 to 12 months); lipids, glucose (yearly if normal); observe for appearance of opportunistic infections [DHHS (adult), 2014])
Monitor CD4 count every 3 to 6 months; every 6 to 12 months once clinically stable. For patients who have been on ART for at least 2 years with consistent viral suppression, CD4 count frequency may be reduced to every 12 months for CD4 count 300 to 500 cells/mm3 and is considered optional for CD4 count > 500 cells/mm3. Resume more frequent CD4 count monitoring in patients with viral rebound, new HIV-associated clinical symptoms, or when there are conditions or a new therapy that may reduce CD4 cell count (DHHS [adult], 2014]).
Note: Percentages noted with adults unless otherwise stated.
>10%:
Central nervous system: Headache (63%), malaise (53%), fever (children 25%)
Dermatologic: Rash (children 12%)
Gastrointestinal: Nausea (adults 51%; children 8%), anorexia (20%), vomiting (adults 17%; children 8%)
Hematologic: Macrocytosis (children >50%), anemia (neonates 22%; children 4%; adults 1%; onset 2-4 weeks)
Hepatic: Hepatomegaly (children 11%)
Respiratory: Cough (children 15%)
1% to 10%:
Cardiovascular: ECG abnormality (children <6%), edema (children <6%), heart failure (children <6%), left ventricular dilation (children <6%)
Central nervous system: Irritability (children <6%), nervousness (children <6%), chills ( ≥5%), fatigue ( ≥5%), insomnia ( ≥5%)
Gastrointestinal: Diarrhea (children 8%), constipation (6%), weight loss (children <6%), abdominal cramps ( ≥5%), abdominal pain ( ≥5%), dyspepsia ( ≥5%)
Genitourinary: Hematuria (children <6%)
Hematologic: Neutropenia (children 8%), granulocytopenia (2%; onset 6-8 weeks), thrombocytopenia (children 1%)
Hepatic: Transaminases increased (1% to 3%)
Neuromuscular & skeletal: Weakness (9%), arthralgia ( ≥5%), musculoskeletal pain ( ≥5%), myalgia ( ≥5%), neuropathy ( ≥5%)
Otic: Discharge/erythema/pain/swelling (7%)
Postmarketing and/or case reports: Allergic reactions, amblyopia, anaphylaxis, angioedema, anxiety, aplastic anemia, back pain, body fat redistribution, cardiomyopathy, confusion, CPK increased, depression, diabetes, dizziness, dyslipidemias, dyspnea, gynecomastia, hearing loss, hemolytic anemia, hepatitis, hepatomegaly with steatosis, immune reconstitution syndrome, insulin resistance, jaundice, lactic acidosis, LDH increased, leukopenia, loss of mental acuity, lymphadenopathy, macular edema, mania, myopathy, myositis, oral mucosa pigmentation, pancreatitis, pancytopenia with marrow hypoplasia, paresthesia, photophobia, pruritus, pure red cell aplasia, rhabdomyolysis, seizure, skin/nail pigmentation changes (blue), Stevens-Johnson syndrome, syncope, taste perversion, toxic epidermal necrolysis, tremor, urticaria, vertigo
Cl is decreased, resulting in an increased half-life and AUC of zidovudine and major metabolite GZDV.
Concerns related to adverse effects:
- Fat redistribution: May cause redistribution of fat (eg, buffalo hump, peripheral wasting with increased abdominal girth, cushingoid appearance).
- Hematologic toxicity: [US Boxed Warning]: Hematologic toxicity, including neutropenia and severe anemia have been reported with use, especially with advanced HIV-1 disease. Toxicity may be related to duration of use and prior bone marrow reserve. Hemoglobin reduction may occur in as early as 2 to 4 weeks; neutropenia usually occurs after 6 to 8 weeks. Pancytopenia has been reported (usually reversible). Use with caution in patients with bone marrow compromise (granulocytes <1,000 cells/mm3 or hemoglobin <9.5 mg/dL); dose interruption may be required in patients who develop anemia or neutropenia.
- Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves disease, polymyositis, Guillain-Barre syndrome) later in therapy; further evaluation and treatment may be required.
- Lactic acidosis/hepatomegaly: [U.S Boxed Warning]: Lactic acidosis and severe hepatomegaly with steatosis have been reported with nucleoside analogues, including fatal cases. Risks may be increased with liver disease, obesity, pregnancy, prolonged exposure, or in females. Suspend treatment in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or hepatotoxicity (transaminase elevation may/may not accompany hepatomegaly and steatosis).
- Myopathy: [US Boxed Warning]: Prolonged use has been associated with symptomatic myopathy and myositis. Pathological changes observed are similar to that produced by HIV-1 disease.
Disease-related concerns:
- Hepatic impairment: Hematologic toxicity may be increased due to increased serum concentrations in patients with severe hepatic impairment.
- Renal impairment: Use with caution in patients with severe renal impairment; dosage adjustment recommended.
Concurrent drug therapy issues:
- Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
Special populations:
- Newborns: Zidovudine newborn prophylaxis may affect diagnostic virologic assays in HIV-exposed infants. If a virologic assay result is negative while the infant is receiving combination antiretroviral prophylaxis, repeat virologic testing should be considered 2 to 4 weeks after cessation of antiretroviral prophylaxis (HHS [pediatric], 2014).
Dosage form specific issues:
- Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol ( ≥99 mg/kg/day) have been associated with a potentially fatal toxicity ( "gasping syndrome " �) in neonates; the "gasping syndrome " � consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP [Inactive" 1997]; CDC, 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors, 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer 's labeling.
Dosage form specific issues:
- Injection: Latex is used in vial stopper. May cause allergic reactions in latex-sensitive individuals.
Special handling:
- Hazardous agent: Use appropriate precautions for handling and disposal (NIOSH 2014 [group 2]).
C
Adverse events have been observed in some animal reproduction studies. Zidovudine has a high level of transfer across the human placenta and the placenta also metabolizes zidovudine to the active metabolite. No increased risk of overall birth defects has been observed following first trimester exposure according to data collected by the antiretroviral pregnancy registry. Cases of lactic acidosis/hepatic steatosis syndrome related to mitochondrial toxicity have been reported with use of nucleoside analogues. In addition, these adverse events are similar to other rare but life-threatening syndromes which occur during pregnancy (eg, HELLP syndrome). In general nucleoside reverse transcriptase inhibitors are well tolerated and the benefits of use generally outweigh potential risk. The HHS Perinatal HIV Guidelines consider zidovudine in combination with lamivudine to be a preferred NRTI backbone for use in antiretroviral-naive pregnant women. Zidovudine should be administered IV near delivery regardless of antepartum regimen or mode of delivery in women with HIV RNA >1,000 copies/mL or unknown HIV RNA status (even in cases of documented zidovudine resistance). The pharmacokinetics of zidovudine are not significantly altered in pregnancy and dosing adjustment is not needed.
Combination antiretroviral therapy (cART) therapy is recommended for all HIV-infected pregnant women. The goal of therapy is to keep the viral load below the limit of detection and prevent perinatal transmission. Therapy must be individualized. In general, women who become pregnant on a stable cART regimen may continue that regimen if viral suppression is effective, contraindications for use in pregnancy are not present, and the regimen is well tolerated. For HIV-infected couples planning a pregnancy, maximum viral suppression with cART is recommended prior to conception for the HIV-infected partner(s). When HIV is diagnosed during pregnancy in a woman who has never received antiretroviral therapy, cART should be considered as soon as possible after diagnosis to reduce the risk of perinatal transmission. If antiretroviral drug-resistance testing is done, treatment may be started prior to obtaining results, then adjusted accordingly. Monitoring during pregnancy is more frequent than in non-pregnant adults. If cART must be interrupted for <24 hours, stop then restart all medications simultaneously in order to decrease the chance of developing resistance. Long-term follow-up is recommended for all infants exposed to antiretroviral medications; children who develop significant organ system abnormalities (particularly of the CNS or heart) should be evaluated for potential mitochondrial dysfunction.
HIV-infected women not planning a pregnancy may use any available type of contraception, considering possible drug interactions and contraindications of the specific method. In addition, consistent use of condoms is also recommended (even during pregnancy) to prevent transmission of HIV or other sexually-transmitted diseases.
Health care providers are encouraged to enroll pregnant women exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263 or www.APRegistry.com). Health care providers caring for HIV-infected women and their infants may contact the National Perinatal HIV Hotline (888-448-8765) for clinical consultation (HHS [perinatal] 2016).
Zidovudine is a thymidine analog which interferes with the HIV viral RNA-dependent DNA polymerase resulting in inhibition of viral replication; nucleoside reverse transcriptase inhibitor
Oral: Well absorbed
Significant penetration into the CSF
Vd: 1 to 2.2 L/kg
CSF/plasma ratio:
Infants 3 months to Children 12 years (n=38): Median: 0.68; Range: 0.03 to 3.25
Adults (n=39): Median: 0.6; Range: 0.04 to 2.62
Hepatic via glucuronidation to inactive metabolites, including GZDV; extensive first-pass effect
Oral: Urine (72% to 74% as metabolites, 14% to 18% as unchanged drug)
IV: Urine (45% to 60% as metabolites, 18% to 29% as unchanged drug)
Serum: 30 to 90 minutes
Terminal:
Premature neonate: 6.3 hours
Full-term neonates: 3.1 hours
Infants 14 days to 3 months: 1.9 hours
Infants 3 months to Children 12 years: 1.5 hours
Adults: 0.5 to 3 hours (mean 1.1 hours)
25% to 38%
- Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
- Patient may experience constipation, headache, lack of appetite, vomiting, or nausea. Have patient report immediately to prescriber signs of infection, signs of liver problems (dark urine, feeling tired, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes), signs of too much lactic acid in the blood (lactic acidosis; fast breathing, fast heartbeat, abnormal heartbeat, vomiting, drowsiness, shortness of breath, feeling very tired or weak, severe dizziness, feeling cold, or muscle pain or cramps), signs of a pancreas problem (pancreatitis; severe abdominal pain, severe back pain, severe nausea, vomiting), loss of strength and energy, muscle pain, bruising, bleeding, change in body fat, or signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (red, swollen, blistered, or peeling skin [with or without fever]; red or irritated eyes; or sores in mouth, throat, nose, or eyes) (HCAHPS).
- Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.