lamivudine

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

Half-Life: 5–7 hr.

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	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.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Concurrent use of antiretroviral combination products containing lamivudine or emtricitabine.

Use Cautiously in:

Renal impairment (↑ dosing interval/↓ dose if CCr <50 mL/min);
Women and obesity (↑ risk of lactic acidosis and severe hepatomegaly with steatosis);
Patients with HIV who are coinfected with HBV (hepatitis may recur after discontinuation of lamivudine);
OB: Considered a preferred nucleoside reverse transcriptase inhibitor (NRTI) for pregnant patients with HIV infection who are antiretroviral-naive, who have had antiretroviral therapy in the past but are restarting, or who require a new antiretroviral regimen; use has also been studied in pregnant women with HBV;
Lactation: Breastfeeding should be supported in people with HIV who are taking antiretroviral therapy, as prescribed, and are maintaining an undetectable amount of virus in the body;
Pedi: Safety and effectiveness not established in children 3 mo (HIV) or 2 yr (HBV);
Geri: dose may be necessary in older adults due to age-related in renal function.

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

Adv. Reactions/Side Effects ⬆ ⬇

Derm: alopecia, erythema multiforme, rash, urticaria

Endo: hyperglycemia

F and E: lactic acidosis

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

Hemat: anemia, neutropenia, pure red cell aplasia

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

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

Resp: cough

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

Interactions ⬆ ⬇

Drug-drug:

Trimethoprim/sulfamethoxazole may ↑ levels and risk of toxicity; 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 and effectiveness; avoid concurrent use.

Route/Dosage ⬆ ⬇

HIV-1 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.
PO (Children 2–17 yr): 3 mg/kg once daily (up to 100 mg/day).

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.

Availability ⬆ ⬇

(Generic available)

Tablets: 100 mg; 150 mg; 300 mg
Oral solutionstrawberry-banana flavor: 10 mg/mL
In combination with: abacavir; abacavir and dolutegravir (Triumeq, Triumeq PD); abacavir and zidovudine; doravirine and tenofovir disoproxil fumarate (Delstrigo); efavirenz and tenofovir disoproxil fumarate (Symfi, Symfi Lo); dolutegravir (Dovato); tenofovir disoproxil fumarate (Cimduo); zidovudine. See Appendix [not included in this PDA edition].

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 ↑ AST, ALT, CK, 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.

Implementation ⬆ ⬇

Do not confuse lamivudine with lamotrigine.
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. 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 or prevent associated or opportunistic infections. Lamivudine may 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.
- Advise females of reproductive potential using hormonal contraceptives to use an alternative nonhormonal method of contraception. Advise patient to notify health care professional if pregnancy is planned or suspected. 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.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇