lamiVUDine

General

Pronunciation:
la-mi-vyoo-deen


Trade Name(s)

  • 3TC Canadian Tradename
  • Epivir
  • Epivir-HBV
  • Heptovir Canadian Tradename

Ther. Class.
antiretrovirals
antivirals

Pharm. Class.
nucleoside reverse transcriptase inhibitors

Indications

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

Unlabeled Use(s):

Part of HIV-postexposure prophylaxis with zidovudine and indinavir.

Action

After intracellular conversion to its active form (lamivudine-5-triphosphate), inhibits viral DNA synthesis by inhibiting the enzyme reverse transcriptase.

Therapeutic Effect(s):

  • Slows the progression of HIV infection and decreases the occurrence of its sequelae.
  • Increases CD4 cell counts and decreases viral load.
  • Protection from liver damage caused by chronic hepatitis B infection; decreases viral load.

Pharmacokinetics

Absorption: Well absorbed after oral administration (86% in adults, 66% in infants and children).

Distribution: Distributes into the extravascular space. Some penetration into CSF; remainder of distribution unknown.

Metabolism and Excretion: Mostly excreted unchanged in urine; <5% metabolized by the liver.

Half-life: Adults– 3.7 hr;  children– 2 hr.

TIME/ACTION PROFILE (blood levels)

ROUTEONSETPEAKDURATION
POunknown 0.9 hr†12 hr
†On an empty stomach; peak levels occur at 3.2 hr if lamivudine is taken with food. Food does not affect total amount of drug absorbed.

Contraindication/Precautions

Contraindicated in:

  • Hypersensitivity;
  • Concurrent use of antiretroviral combination products containing lamivudine or emtricitabine
  • Lactation: Breast feeding not recommended for HIV positive mothers.

Use Cautiously in:

  • Impaired renal function (↑ dosing interval/↓ dose if CCr <50 mL/min);
  • Women and obesity (↑ risk of lactic acidosis and severe hepatomegaly with steatosis);
  • Coinfection with hepatitis B (hepatitis may recur after discontinuation of lamivudine; Epivir HBV is not indicated for treatment of HIV because lamivudine dosage is subtherapeutic);
  • OB:  Pedi:  Pregnancy or children <3 mo (safety not established);
  • Geri:  ↓ dose may be necessary due to age-related ↓ in renal function.

Exercise Extreme Caution in:

Pedi:  Pediatric patients with a history of or significant risk factors for pancreatitis (use only if no alternative).

Adverse Reactions/Side Effects

Noted for combination of lamivudine plus zidovudine

Derm: alopecia, erythema multiforme, rash, urticaria

Endo: hyperglycemia

F and E: lactic acidosis

GI: HEPATOMEGALY WITH STEATOSIS, PANCREATITIS (↑ IN PEDIATRIC PATIENTS), anorexia, diarrhea, nausea, vomiting, abdominal discomfort, ↑ liver enzymes, dyspepsia

Hemat: anemia, neutropenia, pure red cell aplasia

MS: musculoskeletal pain, arthralgia, muscle weakness, myalgia, rhabdomyolysis

Neuro: neuropathy, SEIZURES, fatigue, headache, insomnia, malaise, depression, dizziness

Resp: cough

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS), immune reconstitution syndrome

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

  •  Trimethoprim/sulfamethoxazole  may ↑ levels (dose alteration may be necessary in renal impairment).
  • ↑ risk of pancreatitis with concurrent use of other  drugs causing pancreatitis.
  • ↑ risk of neuropathy with concurrent use of other  drugs causing neuropathy.
  • Combination therapy with  tenofovir  and  abacavir  may lead to virologic nonresponse and should not be used.
  •  Sorbitol  may ↓ levels; avoid concurrent use.

Route/Dosage

HIV infection

PO (Adults): 150 mg twice daily or 300 mg once daily.

PO (Children  ≥3 mo): Oral solution– 5 mg/kg twice daily or 10 mg/kg once daily (max dose = 300 mg/day);  Tablets– 14–19 kg: 75 mg twice daily or 150 mg once daily; 20–24 kg: 75 mg in AM, 150 mg in PM or 225 mg once daily; ≥25 kg: 150 mg twice daily or 300 mg once daily.

Renal Impairment 
(Adults and Children ≥25 kg): CCr 30–49 mL/min– 150 mg once daily;  CCr 15–29 mL/min– 150 mg initially, then 100 mg once daily;  CCr 5–14 mL/min– 150 mg initially, then 50 mg once daily;  CCr <5 mL/min– 50 mg initially, then 25 mg once daily.

Chronic Hepatitis B

PO (Adults): 100 mg once daily.

Renal Impairment 
PO (Adults): CCr 30–49 mL/min– 100 mg first dose, then 50 mg once daily;  CCr 15–29 mL/min– 100 mg first dose, then 25 mg once daily;   CCr 5–14 mL/min– 35 mg first dose, then 15 mg once daily;  CCr <5 mL/min– 35 mg first dose, then 10 mg once daily.

PO (Children 2–17 yr): 3 mg/kg once daily (up to 100 mg/day).

Availability (generic available)

Epivir

Oral solution (strawberry-banana flavor): 10 mg/mL

Tablets: 150 mg, 300 mg

In Combination with: abacavir (Epzicom); abacavir and dolutegravir (Triumeq); efavirenz and tenofovir disoproxil fumarate (Symfi); lamivudine (Dovato); tenofovir disoproxil fumarate (Cimduo, Temixys); zidovudine (Combivir); zidovudine and abacavir (Trizivir). See combination drugs.

Epivir-HBV

Oral solution (strawberry-banana flavor): 5 mg/mL

Tablets: 100 mg

Assessment

  • Assess patient, especially pediatric patients, for signs of pancreatitis (nausea, vomiting, abdominal pain) periodically during therapy. May require discontinuation of therapy.
  • HIV:

    Assess patient for change in severity of symptoms of HIV infection and for symptoms of opportunistic infection during therapy.

    • Monitor patient for signs and symptoms of peripheral neuropathy (tingling, burning, numbness, or pain in hands or feet); may be difficult to differentiate from peripheral neuropathy of severe HIV disease. May require discontinuation of therapy.
  • Chronic Hepatitis B Infection: Monitor signs of hepatitis (jaundice, fatigue, anorexia, pruritus) during therapy.

Lab Test Considerations:

Monitor viral load and CD4 levels before and periodically during therapy.

  • Monitor serum amylase, lipase, and triglycerides periodically during therapy. Elevated serum levels may indicate pancreatitis and require discontinuation.
  • Monitor liver function. May cause ↑ levels of AST, ALT, CPK, bilirubin, and alkaline phosphatase, which usually resolve after interruption of therapy. Lactic acidosis may occur with hepatic toxicity causing hepatic steatosis; may be fatal, especially in women.
  • May rarely cause neutropenia and anemia.

Potential Diagnoses

Implementation

  • Do not confuse lamivudine with lamotrigine. Do not confuse Epivir tablets and oral solution with Epivir-HBV tablets and oral solutions. Epivir Tablets and Oral Solution contain a higher dose of the same active ingredient (lamivudine) as Epivir-HBV Tablets and Oral Solution. Epivir-HBV was developed for patients with hepatitis B; do not use for patients dually infected with HIV and hepatitis B; use may lead to lamivudine-resistant HIV due to subtherapeutic dose.
  • PO 

    May be administered without regard to food.

    • Epivir scored tablet is preferred for HIV-1-infected pediatric patients weighing at least 14 kg and able to swallow pill; solution is associated with higher resistance rates. Before prescribing, assess for ability to swallow tablets. For patients unable to safely and reliably swallow tablets, oral solution may be used.

Patient/Family Teaching

Instruct patient to take lamivudine as directed, every 12 hr. Explain the difference between Epivir and Epivir-HBV to patients. Emphasize the importance of compliance with full course of therapy, not taking more than the prescribed amount, and not discontinuing without consulting health care professional; discontinuation may lead to deterioration of liver disease. Take missed doses as soon as possible unless almost time for next dose. Do not double doses. Caution patient not to share medication with others. Advise patient to read  Patient Information  before starting and with each Rx refill in case of changes.

  • Inform patient that lamivudine does not cure HIV disease or prevent associated or opportunistic infections. Lamivudine does not reduce the risk of transmission of HIV to others through sexual contact or blood contamination. Caution patient to use a condom during sexual contact and avoid sharing needles or donating blood to prevent spreading HIV to others. Advise patient that the long-term effects of lamivudine are unknown at this time.
  • Instruct patient to notify health care professional promptly if signs of peripheral neuropathy, pancreatitis, lactic acidosis (feel very weak or tired; feel cold, especially in arms and legs; unusual muscle pain; feel dizzy or light-headed; trouble breathing; fast or irregular heartbeat; stomach pain with nausea and vomiting), liver problems (yellowing of skin or white part of eyes; loss of appetite; nausea; dark or "tea-colored" urine; pain, aching, or tenderness on right side of abdomen; light-colored stools) or Immune Reconstitution Syndrome (signs and symptoms of an infection, Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia, tuberculosis) occur.
  • Inform patient that redistribution and accumulation of body fat may occur, causing central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, breast enlargement, and cushingoid appearance. The cause and long-term effects are not known.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, or herbal products.
  • Rep:  Instruct females using hormonal contraceptives to use an alternative nonhormonal method of contraception. Advise patient to notify health care professional if pregnancy is planned or suspected and to avoid breast feeding. If pregnant patient is exposed to lamivudine, register patient in  Antiretroviral Pregnancy Registry  by calling 1-800-258-4263.
  • Emphasize the importance of regular follow-up exams and blood tests to determine progress and monitor for side effects.

Evaluation/Desired Outcomes

  • Slowing of the progression of HIV infection and its sequelae.
  • Decrease in viral load and improvement in CD4 levels in patients with advanced HIV infection.
  • Protection from liver damage caused by chronic hepatitis B infection; decreases viral load.
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