Medical term:

Viread


Viread

 [vir´e-ad]
trademark for a preparation of tenofovir disoproxil fumarate, an antiretroviral agent.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

tenofovir disoproxil fumarate

Viread

Pharmacologic class: Nucleoside analog reverse transcriptase inhibitor

Therapeutic class: Antiretroviral

Pregnancy risk category B

FDA Box Warning

Severe acute exacerbations of hepatitis have been reported in patients with hepatitis B virus (HBV) infection who have discontinued anti-hepatitis B therapy. Monitor hepatic function closely with both clinical and laboratory follow-up for at least several months in patients who discontinue anti-hepatitis B therapy. If appropriate, resumption of anti-hepatitis B therapy may be warranted.

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs, including tenofovir.

Drug should not be given with adefovir dipivoxil.

Because of risk of development of human immunodeficiency virus-1 (HIV-1) resistance, drug should only be used in HIV-1 and HBV co-infected patients as part of an appropriate antiretroviral combination regimen.

HIV-1 antibody testing should be offered to all HBV-infected patients before start of therapy. It is also recommended that all patients with HIV-1 infection be tested for presence of chronic HBV infection before start of drug therapy.

Drug's effects on bone haven't been studied in patients with chronic HBV infection.

In HIV-infected patients, redistribution or accumulation of body fat, including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and cushingoid appearance, has been observed in patients receiving combination antiretroviral therapy.

Immune reconstitution syndrome has been reported in HIV-infected patients treated with combination antiretroviral therapy.

Action

Inhibits activity of HIV by competing with natural substrate deoxyadenosine 5'-triphosphate; disrupts cellular DNA by causing chain termination

Availability

Powder, oral: 40 mg/scoop

Tablets: 150 mg, 200 mg, 250 mg, 300 mg

Indications and dosages

➣ HIV-1 infection, chronic hepatitis B infection

Adults and adolescents age 12 and older weighing 35 kg (77 lb) or more: 300 mg P.O. daily; for patients unable to swallow tablets, give 7.5 scoops of oral powder.

➣ HIV-1 infection

Children ages 2 to younger than 12: 8 mg/kg (to maximum of 300 mg) P.O. once daily as oral powder or tablets

Dosage adjustment

• Baseline creatinine clearance less than 50 ml/minute

Contraindications

• None

Precautions

Use cautiously in:

• renal impairment

• lactic acidosis

• exacerbation of hepatitis, hepatomegaly with steatosis

• co-administration of adefovir dipivoxil or other tenofovir-containing products

• concurrent or recent use of nephrotoxic drugs.

• decreased bone marrow density

• redistribution or accumulation of body fat

• immune reconstitution syndrome

• elderly patients

• pregnant or breastfeeding patients

• children younger than age 2 with HIV-1 infection and younger than age 12 or less than 35 kg (77 lb) with chronic hepatitis B infection (safety and efficacy not established).

Administration

• Assess creatinine clearance before starting drug.

• Give tablets without regard to meals.

• Give oral powder with 2 to 4 oz of soft foods that can be swallowed without chewing (such as applesauce, baby food, or yogurt). Don't mix with liquids. Give dose immediately after mixing.

• Know that drug is usually given with other antiretrovirals for HIV infection.

Adverse reactions

CNS: headache, asthenia, depression

GI: nausea, vomiting, diarrhea, abdominal pain, flatulence, anorexia

GU: new-onset or worsening renal impairment (including acute renal failure and Fanconi syndrome)

Skin: rash

Hepatic: severe hepatomegaly with steatosis

Metabolic: hyperglycemia, lactic acidosis

Other: body fat redistribution, pain, immune reconstitution syndrome

Interactions

Drug-drug. Acyclovir, cidofovir, didanosine, ganciclovir, indinavir, lopinavir, probenecid, ritonavir, valacyclovir, valganciclovir, other drugs eliminated by active tubular secretion (such as adefovir dipivoxil): increased blood level of either drug

Atazanavir, lopinavir/ritonavir: increased tenofovir concentration

Drug-diagnostic tests. Alanine aminotransferase, amylase, aspartate aminotransferase, blood and urine glucose, creatine kinase, triglycerides: increased levels

Neutrophils: decreased count

Drug-food. Any food: decreased drug bioavailability and efficacy

Patient monitoring

Watch for and report signs and symptoms of lactic acidosis or hepatotoxicity.

• Monitor bone mineral density in patients with history of pathologic fractures or who are at risk for osteopenia.

Monitor for signs of immune reconstitution syndrome, especially during initial phase of combination antiretroviral treatment when patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci pneumonia, or tuberculosis), which may necessitate further evaluation and treatment.

• Monitor kidney and liver function tests.

• Assess nutritional status and hydration in light of adverse GI reactions and underlying disease.

Patient teaching

• Tell patient to take tablets once daily at the same time every day with or without food and take oral powder at the same time every day with food.

• Tell patient not to mix oral powder with liquids. Tell patient to use only the dosing scoop supplied, to mix only with 2 to 4 oz of soft foods that can be swallowed without chewing (such as baby food, applesauce, or yogurt), and to take entire dose immediately after mixing.

Instruct patient to immediately report unusual tiredness or yellowing of skin or eyes.

• Tell patient drug may cause weakness and headache. Caution him to avoid driving and other hazardous activities until he knows how drug affects performance.

• Caution female patient not to breastfeed.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved

tenofovir

(te-noe-fo-veer) ,

Viread

(trade name)

Classification

Therapeutic: antiretrovirals
Pharmacologic: nucleoside reverse transcriptase inhibitors
Pregnancy Category: B

Indications

HIV infection (with other antiretrovirals).Chronic hepatitis B.

Action

Active drug (tenofovir) is phosphorylated intracellularly; tenofovir diphosphate inhibits HIV reverse transcriptase resulting in disruption of DNA synthesis.

Therapeutic effects

Slowed progression of HIV infection and decreased occurrence of sequelae.
Increased CD4 cell count and decreased viral load.
Decreased progression/sequelae of chronic hepatitis B infection.

Pharmacokinetics

Absorption: Tenofovir disoproxil fumarate is a prodrug, which is split into tenofovir, the active component.
Distribution: Absorption is enhanced by food.
Metabolism and Excretion: 70–80% excreted unchanged in urine by glomerular filtration and active tubular secretion.
Half-life: Unknown.

Time/action profile (blood levels)

ROUTEONSETPEAKDURATION
POunknown2 hr*24 hr
*When taken with food

Contraindications/Precautions

Contraindicated in: Hypersensitivity;Concurrent use of antiretroviral combination products containing tenofovirConcurrent or recent use of NSAIDs (↑ risk of acute renal failure) Lactation: HIV-infected women should not breast feed.
Use Cautiously in: Co-infection with HIV and chronic hepatitis B;Obesity, women, prolonged nucleoside exposure (may be risk factors for lactic acidosis/hepatomegaly);Renal impairment (↑ dosing interval if CCr <50 mL/min);History of pathologic bone fractures or at risk for osteopenia; Obstetric: Has been used safely; Pediatric: Children <2 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • depression (most frequent)
  • headache (most frequent)
  • weakness

Gastrointestinal

  • hepatomegaly (life-threatening)
  • (with steatosis)
  • diarrhea (most frequent)
  • nausea (most frequent)
  • abdominal pain
  • anorexia
  • vomiting
  • flatulence

Genitourinary

  • proximal renal tubulopathy
  • renal impairment

Fluid and Electrolyte

  • lactic acidosis (life-threatening)
  • hypophosphatemia

Dermatologic

  • rash (most frequent)

Musculoskeletal

  • ↓ bone mineral density
  • osteomalacia

Miscellaneous

  • immune reconstitution syndrome

Interactions

Drug-Drug interaction

May ↑ didanosine levels; ↓ didanosine dose.Blood levels may be ↑ by cidofovir, acyclovir, ganciclovir, or valganciclovir.Risk of renal toxicity ↑ by other nephrotoxic agents.Combination therapy with atazanavir may lead to ↓ virologic response and possible resistance to atazanavir (small amounts of ritonavir may be added to boost blood levels); may also ↑ tenofovir levels.Lopinavir/ritonavir may ↑ levels.Concurrent use with adefovir for chronic hepatitis B infection should be avoided.Concurrent use with NSAIDs may ↑ risk of acute renal failure

Route/Dosage

HIV

Oral (Adults and Children ≥12 yr and ≥35 kg) 300 mg once daily

Renal Impairment

Oral (Adults ) CCr 30–49 mL/min—300 mg every 48 hr; CCr 10–29 mL/min—300 mg every 72–96 hr; Hemodialysis patients—300 mg every 7 days following dialysis.
Oral (Children 2–11 yr and ≥17 kg) Tablets:: ≥35 kg—300 mg once daily; 28–34.9 kg—250 mg once daily; 22–27.9 kg—200 mg once daily; 17–21.9 kg—150 mg once daily;.
Oral (Children 2–11 yr) Oral Powder:: ≥35 kg—7.5 scoops (300 mg) once daily; 34–34.9 kg—7 scoops (280 mg) once daily; 32–33.9 kg—6.5 scoops (260 mg) once daily; 29–31.9 kg—6 scoops (240 mg) once daily; 27–28.9 kg—5.5 scoops (220 mg) once daily; 24–26.9 kg—5 scoops (200 mg) once daily; 22–23.9 kg—4.5 scoops (180 mg) once daily; 19–21.9 kg—4 scoops (160 mg) once daily; 17–18.9 kg—3.5 scoops (140 mg) once daily; 14–16.9 kg—3 scoops (120 mg) once daily; 12–13.9 kg—2.5 scoops (100 mg) once daily; 10–11.9 kg—2 scoops (80 mg) once daily;.

Chronic Hepatitis B

Oral (Adults and Children ≥12 yr and ≥35 kg) 300 mg once daily

Renal Impairment

Oral (Adults ) CCr 30–49 mL/min—300 mg every 48 hr; CCr 10–29 mL/min—300 mg every 72–96 hr; Hemodialysis patients—300 mg every 7 days following dialysis.

Availability

Tablets: 150 mg, 200 mg, 250 mg, 300 mg
Oral powder: 40 mg/scoop
In combination with: emtricitabine (Truvada); emtricitabine and rilpivirine (Complera); efavirenz and emtricitabine (Atripla); elvitegravir, cobicistat, and emtricitabine (Stribild). See combination drugs.

Nursing implications

Nursing assessment

  • Monitor for change in severity of HIV symptoms and for symptoms of opportunistic infection before and during therapy.
  • Monitor bone mineral density in patients who have a history of pathologic bone fracture or are at risk for osteoporosis or bone loss.
  • Lab Test Considerations: Monitor viral load and CD4 count before and routinely during therapy to determine response.
    • Monitor liver function tests and hepatitis B virus levels throughout and following therapy. If therapy is discontinued, may cause severe exacerbation of hepatitis B. May cause ↑ AST, ALT, alkaline phosphatase, creatine kinase, amylase, and triglyceride concentrations. Lactic acidosis may occur with hepatic toxicity causing hepatic steatosis; may be fatal, especially in women.
    • Calculate creatinine clearance prior to and periodically during therapy and when clinically indicated.
    • Monitor serum phosphate periodically during therapy in patients at risk for renal impairment. May cause hypophosphatemia in patients with renal impairment.
    • May cause hyperglycemia and glucosuria.

Potential Nursing Diagnoses

Risk for infection (Indications,  Side Effects)
Risk for injury (Side Effects)

Implementation

  • When tenofovir is administered concomitantly with didanosine, administer tenofovir 2 hr before or 1 hr after didanosine.
  • Oral: Administer once daily with or without food.
    • Patients unable to swallow tablets can use oral powder. Using only dosing scoop, mix in soft food (applesauce, baby food, yogurt). Do not mix in liquid; powder floats to top even after stirring. Ingest entire mixture immediately to avoid bitter taste.

Patient/Family Teaching

  • Instruct patient on the importance of taking tenofovir as directed, even if feeling better. Do not take more than prescribed amount and do not stop taking without consulting health care professional. Discontinuing therapy may lead to severe exacerbations. Take missed doses as soon as remembered unless almost time for next dose; do not double doses. Caution patient not to share or trade this medication with others.
  • Inform patient that tenofovir may cause hyperglycemia. Advise patient to notify health care professional if increased thirst or hunger; unexplained weight loss; increased urination; fatigue; or dry, itchy skin occurs.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Caution patient to avoid crowds and persons with known infections.
  • Inform patient that tenofovir does not cure AIDS and does not reduce the risk of transmission of HIV to others through sexual contact or blood contamination. Caution patient to use a condom and avoid sharing needles or donating blood to prevent spreading HIV to others.
  • Advise patient to notify health care professional immediately if symptoms of lactic acidosis (nausea, vomiting, unusual or unexpected stomach discomfort, and weakness) or signs of Immune Reconstitution Syndrome (signs and symptoms of an infection) occur.
  • Inform patient that changes in body fat distribution (increased fat in upper back and neck, breast, and trunk, and loss of fat from legs, arms, and face) may occur, but may not be related to drug therapy.
  • Advise female patients to notify health care professional if pregnancy is planned or suspected. Breast feeding should be avoided. Pregnancy registry is available for patient taking antiretroviral medications.
  • Emphasize the importance of regular exams to monitor for side effects.

Evaluation/Desired Outcomes

  • Decreased incidence of opportunistic infection and slowed progression of HIV infection.
  • Slowed progression of chronic hepatitis B infection.
Drug Guide, © 2015 Farlex and Partners

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