Lamivudine - Revision history

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Created page with "Lamivudine (3TC) is a nucleoside reverse transcriptase inhibitor (NRTI) used in combination with other antiretrovirals for HIV-1 treatment and as a standalone agent for chronic hepatitis B (HBV). It is a cytidine analog functionally interchangeable with emtricitabine (FTC) — the two should '''never''' be combined. Lamivudine is found in the widely prescribed fixed-dose combinations Triumeq, Dovato, Epzicom, and Combivir.<ref name..."

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Lamivudine (3TC) is a nucleoside reverse transcriptase inhibitor (NRTI) used in combination with other antiretrovirals for [[HIV - AIDS (main)|HIV-1]] treatment and as a standalone agent for chronic hepatitis B (HBV). It is a cytidine analog functionally interchangeable with [[Emtricitabine|emtricitabine (FTC)]] — the two should '''never''' be combined. Lamivudine is found in the widely prescribed fixed-dose combinations Triumeq, Dovato, Epzicom, and Combivir.<ref name="EpivirPI">Epivir (lamivudine) [prescribing information]. Research Triangle Park, NC: ViiV Healthcare; 2017.</ref>

'''Critical dosing distinction:''' Lamivudine is marketed at two different doses — '''Epivir''' (150 mg/300 mg for HIV) and '''Epivir-HBV''' (100 mg for hepatitis B). Using the lower HBV dose in an HIV/HBV co-infected patient will provide subtherapeutic HIV coverage and rapidly select for HIV resistance.<ref name="EpivirPI"/>

==Administration==
Type: Nucleoside reverse transcriptase inhibitor (NRTI); cytidine analog
Dosage Forms: 150 mg scored tablets, 300 mg tablets; 10 mg/mL oral solution (Epivir for HIV); 100 mg tablets, 5 mg/mL oral solution (Epivir-HBV)
Routes of Administration: Oral
Common Trade Names: Epivir (HIV dose), Epivir-HBV (hepatitis B dose); also in fixed-dose combinations: Triumeq ([[Dolutegravir]]/[[Abacavir|abacavir]]/lamivudine), Dovato ([[Dolutegravir|dolutegravir]]/lamivudine), Epzicom (abacavir/lamivudine), Combivir ([[Zidovudine|zidovudine]]/lamivudine), Trizivir (abacavir/zidovudine/lamivudine)

==Adult Dosing==
'''HIV treatment:''' 300 mg PO once daily, or 150 mg PO twice daily<ref name="EpivirPI"/>
'''Hepatitis B (Epivir-HBV):''' 100 mg PO once daily ('''do not use this dose for HIV''')<ref name="EpivirPI"/>
'''HIV/HBV co-infection:''' Use the '''HIV dose''' (300 mg daily) as part of combination ART<ref name="EpivirPI"/>
May take with or without food
Scored tablets preferred over oral solution (solution has lower bioavailability; sorbitol-containing coadministered medications further reduce lamivudine exposure)<ref name="EpivirPI"/>

==Pediatric Dosing==
Approved for HIV treatment in patients ≥3 months<ref name="EpivirPI"/>
'''Weight-based:''' 5 mg/kg PO twice daily or 10 mg/kg PO once daily (max 300 mg/day)
Tablets preferred for children ≥14 kg (oral solution associated with lower virologic suppression rates in the ARROW trial)<ref name="EpivirPI"/>
Neonatal dosing available for perinatal prophylaxis regimens

==Special Populations==
===[[Drug pregnancy categories|Pregnancy Rating]]===
Extensively studied in pregnancy; APR data show no increased birth defect risk compared to background<ref name="EpivirPI"/>
Crosses the placenta; widely used as part of preferred NRTI backbone in pregnancy
Antiretroviral Pregnancy Registry: 1-800-258-4263

===Lactation risk===
Excreted in human milk; women with HIV should discuss risks and benefits of breastfeeding with their provider<ref name="EpivirPI"/>

===Renal Dosing===
Adult (primarily renally eliminated; dose reduction required):<ref name="EpivirPI"/>
CrCl 30–49 mL/min: 150 mg PO once daily
CrCl 15–29 mL/min: 150 mg first dose, then 100 mg PO once daily
CrCl 5–14 mL/min: 150 mg first dose, then 50 mg PO once daily
CrCl <5 mL/min: 50 mg first dose, then 25 mg PO once daily
**No additional dosing required after routine hemodialysis or peritoneal dialysis
Pediatric: Insufficient data; consider proportional reduction

===Hepatic Dosing===
Adult: No dose adjustment needed (pharmacokinetics not significantly altered by hepatic impairment)<ref name="EpivirPI"/>
Pediatric: No specific data

==Contraindications==
Allergy to class/drug
Do '''not''' coadminister with [[Emtricitabine|emtricitabine]]-containing products (therapeutic duplication — both are cytidine analogs with overlapping resistance profiles)<ref name="EpivirPI"/>

==Adverse Reactions==
===Serious===
'''Hepatitis B flare (Boxed Warning):''' Severe, acute exacerbations of HBV (including hepatic decompensation and failure) reported in HIV/HBV co-infected patients who discontinue lamivudine-containing regimens. Monitor hepatic function closely for at least several months after stopping<ref name="EpivirPI"/>
'''Lactic acidosis with hepatic steatosis''' (NRTI class effect; including fatal cases)<ref name="EpivirPI"/>
Pancreatitis (rare; more common in pediatric patients)<ref name="EpivirPI"/>
[[Immune reconstitution syndrome|Immune reconstitution inflammatory syndrome (IRIS)]]

===Common===
Headache, nausea, malaise, fatigue, nasal symptoms, diarrhea, cough<ref name="EpivirPI"/>
Insomnia
Musculoskeletal pain
Elevated transaminases, CPK

==Pharmacology==
Half-life: ~5–7 hours (plasma); intracellular triphosphate half-life ~10–15 hours<ref name="EpivirPI"/>
Bioavailability: ~86%<ref name="EpivirPI"/>
Protein Binding: <36%<ref name="EpivirPI"/>
Metabolism: Minimal hepatic metabolism; not a CYP450 substrate and does not inhibit or induce CYP enzymes<ref name="EpivirPI"/>
Excretion: ~70% unchanged in urine via glomerular filtration and active organic cationic tubular secretion<ref name="EpivirPI"/>

==Mechanism of Action==
Lamivudine is a cytidine analog that is intracellularly phosphorylated to its active form, lamivudine triphosphate. This competes with the natural substrate deoxycytidine triphosphate for incorporation by HIV-1 reverse transcriptase. Once incorporated into viral DNA, it acts as a chain terminator due to the absence of a 3'-hydroxyl group. Lamivudine triphosphate also inhibits HBV polymerase, which accounts for its dual HIV/HBV activity.<ref name="EpivirPI"/>

==Comments==
'''Epivir vs. Epivir-HBV — the critical dosing trap:''' If an HIV/HBV co-infected patient is accidentally prescribed Epivir-HBV (100 mg) instead of Epivir (150/300 mg), they are receiving subtherapeutic HIV coverage which will rapidly select for resistant HIV. Always verify the formulation and dose in co-infected patients<ref name="EpivirPI"/>
'''Hepatitis B flare on discontinuation:''' Identical to the emtricitabine pearl — lamivudine has anti-HBV activity. Stopping any lamivudine-containing regimen (Triumeq, Dovato, Epzicom, Combivir, etc.) in an HIV/HBV co-infected patient can trigger a '''severe HBV flare''' presenting as acute liver failure. Check HBV serologies and LFTs in any HIV patient with jaundice or transaminase elevation after recent ARV discontinuation<ref name="EpivirPI"/>
'''Emtricitabine duplication:''' Lamivudine and emtricitabine are functionally interchangeable — '''never''' combine them. Check the full medication list when reconciling ARVs (e.g., a patient on Dovato [dolutegravir/lamivudine] should not also receive Descovy [emtricitabine/TAF])
'''Sorbitol interaction:''' Sorbitol-containing liquid medications significantly reduce lamivudine oral solution exposure. Avoid coadministration when possible; this is relevant in pediatric patients receiving multiple liquid formulations<ref name="EpivirPI"/>
'''TMP-SMX interaction:''' Trimethoprim increases lamivudine levels by ~40% via competition for renal organic cationic secretion. No dose adjustment at standard TMP-SMX doses, but '''avoid high-dose TMP-SMX''' (PCP treatment doses) with lamivudine when possible<ref name="EpivirPI"/>
'''Low drug interaction profile:''' Not CYP450-metabolized; does not affect levels of other drugs. Very safe from an interaction standpoint when prescribing in the ED
'''Low resistance barrier:''' The M184V/I mutation emerges rapidly with lamivudine monotherapy or subtherapeutic dosing. This is why proper combination therapy and correct dosing (HIV vs. HBV formulation) are essential
Overdose: No specific antidote; supportive care. No significant symptoms reported in acute overdoses. No additional dosing needed after dialysis<ref name="EpivirPI"/>

==See Also==
[[HIV - AIDS (main)]]
[[HIV post-exposure prophylaxis]]
[[Immune reconstitution syndrome]]
[[Emtricitabine/tenofovir]]
[[Emtricitabine]]
[[Dolutegravir]]

==References==
{{reflist|2}}
[[Category:Pharmacology]]

← Revisión anterior		Revisión del 09:12 22 mar 2026
Línea 1:		Línea 1:
	Lamivudine (3TC) is a nucleoside reverse transcriptase inhibitor (NRTI) used in combination with other antiretrovirals for [[HIV - AIDS (main)\|HIV-1]] treatment and as a standalone agent for chronic hepatitis B (HBV). It is a cytidine analog functionally interchangeable with [[Emtricitabine\|emtricitabine (FTC)]] — the two should '''never''' be combined. Lamivudine is found in the widely prescribed fixed-dose combinations Triumeq, Dovato, Epzicom, and Combivir.<ref name="EpivirPI">Epivir (lamivudine) [prescribing information]. Research Triangle Park, NC: ViiV Healthcare; 2017.</ref>		Lamivudine (3TC) is a nucleoside reverse transcriptase inhibitor (NRTI) used in combination with other antiretrovirals for [[HIV - AIDS (main)\|HIV-1]] treatment and as a standalone agent for chronic hepatitis B (HBV). It is a cytidine analog functionally interchangeable with [[Emtricitabine\|emtricitabine (FTC)]] — the two should '''never''' be combined. Lamivudine is found in the widely prescribed fixed-dose combinations Triumeq, Dovato, Epzicom, and Combivir.<ref name="EpivirPI">Epivir (lamivudine) [prescribing information]. Research Triangle Park, NC: ViiV Healthcare; 2017.</ref>

	~~'''~~Critical dosing distinction:~~'''~~ Lamivudine is marketed at two different doses — ~~'''~~Epivir~~'''~~ (150 mg/300 mg for HIV) and ~~'''~~Epivir-HBV~~'''~~ (100 mg for hepatitis B). Using the lower HBV dose in an HIV/HBV co-infected patient will provide subtherapeutic HIV coverage and rapidly select for HIV resistance.<ref name="EpivirPI"/>		Critical dosing distinction: Lamivudine is marketed at two different doses — Epivir (150 mg/300 mg for HIV) and Epivir-HBV (100 mg for hepatitis B). Using the lower HBV dose in an HIV/HBV co-infected patient will provide subtherapeutic HIV coverage and rapidly select for HIV resistance.<ref name="EpivirPI"/>

	==Administration==		==Administration==
Línea 10:		Línea 10:

	==Adult Dosing==		==Adult Dosing==
	*~~'''~~HIV treatment:~~'''~~ 300 mg PO once daily, or 150 mg PO twice daily<ref name="EpivirPI"/>		*HIV treatment: 300 mg PO once daily, or 150 mg PO twice daily<ref name="EpivirPI"/>
	*'''Hepatitis B (Epivir-HBV):''' 100 mg PO once daily ('''do not use this dose for HIV''')<ref name="EpivirPI"/>		*'''Hepatitis B (Epivir-HBV):''' 100 mg PO once daily ('''do not use this dose for HIV''')<ref name="EpivirPI"/>
	*~~'''~~HIV/HBV co-infection:~~'''~~ Use the ~~'''~~HIV dose~~'''~~ (300 mg daily) as part of combination ART<ref name="EpivirPI"/>		*HIV/HBV co-infection: Use the HIV dose (300 mg daily) as part of combination ART<ref name="EpivirPI"/>
	*May take with or without food		*May take with or without food
	*Scored tablets preferred over oral solution (solution has lower bioavailability; sorbitol-containing coadministered medications further reduce lamivudine exposure)<ref name="EpivirPI"/>		*Scored tablets preferred over oral solution (solution has lower bioavailability; sorbitol-containing coadministered medications further reduce lamivudine exposure)<ref name="EpivirPI"/>
Línea 18:		Línea 18:
	==Pediatric Dosing==		==Pediatric Dosing==
	*Approved for HIV treatment in patients ≥3 months<ref name="EpivirPI"/>		*Approved for HIV treatment in patients ≥3 months<ref name="EpivirPI"/>
	*~~'''~~Weight-based:~~'''~~ 5 mg/kg PO twice daily or 10 mg/kg PO once daily (max 300 mg/day)		*Weight-based: 5 mg/kg PO twice daily or 10 mg/kg PO once daily (max 300 mg/day)
	*Tablets preferred for children ≥14 kg (oral solution associated with lower virologic suppression rates in the ARROW trial)<ref name="EpivirPI"/>		*Tablets preferred for children ≥14 kg (oral solution associated with lower virologic suppression rates in the ARROW trial)<ref name="EpivirPI"/>
	*Neonatal dosing available for perinatal prophylaxis regimens		*Neonatal dosing available for perinatal prophylaxis regimens
Línea 46:		Línea 46:
	==Contraindications==		==Contraindications==
	*Allergy to class/drug		*Allergy to class/drug
	*Do ~~'''~~not~~'''~~ coadminister with [[Emtricitabine\|emtricitabine]]-containing products (therapeutic duplication — both are cytidine analogs with overlapping resistance profiles)<ref name="EpivirPI"/>		*Do not coadminister with [[Emtricitabine\|emtricitabine]]-containing products (therapeutic duplication — both are cytidine analogs with overlapping resistance profiles)<ref name="EpivirPI"/>

	==Adverse Reactions==		==Adverse Reactions==
Línea 72:		Línea 72:

	==Comments==		==Comments==
	*~~'''~~Epivir vs. Epivir-HBV — the critical dosing trap:~~'''~~ If an HIV/HBV co-infected patient is accidentally prescribed Epivir-HBV (100 mg) instead of Epivir (150/300 mg), they are receiving subtherapeutic HIV coverage which will rapidly select for resistant HIV. Always verify the formulation and dose in co-infected patients<ref name="EpivirPI"/>		*Epivir vs. Epivir-HBV — the critical dosing trap: If an HIV/HBV co-infected patient is accidentally prescribed Epivir-HBV (100 mg) instead of Epivir (150/300 mg), they are receiving subtherapeutic HIV coverage which will rapidly select for resistant HIV. Always verify the formulation and dose in co-infected patients<ref name="EpivirPI"/>
	*~~'''~~Hepatitis B flare on discontinuation:~~'''~~ Identical to the emtricitabine pearl — lamivudine has anti-HBV activity. Stopping any lamivudine-containing regimen (Triumeq, Dovato, Epzicom, Combivir, etc.) in an HIV/HBV co-infected patient can trigger a ~~'''~~severe HBV flare~~'''~~ presenting as acute liver failure. Check HBV serologies and LFTs in any HIV patient with jaundice or transaminase elevation after recent ARV discontinuation<ref name="EpivirPI"/>		*Hepatitis B flare on discontinuation: Identical to the emtricitabine pearl — lamivudine has anti-HBV activity. Stopping any lamivudine-containing regimen (Triumeq, Dovato, Epzicom, Combivir, etc.) in an HIV/HBV co-infected patient can trigger a severe HBV flare presenting as acute liver failure. Check HBV serologies and LFTs in any HIV patient with jaundice or transaminase elevation after recent ARV discontinuation<ref name="EpivirPI"/>
	*'''Emtricitabine duplication:''' Lamivudine and emtricitabine are functionally interchangeable — '''never''' combine them. Check the full medication list when reconciling ARVs (e.g., a patient on Dovato [dolutegravir/lamivudine] should not also receive Descovy [emtricitabine/TAF])		*'''Emtricitabine duplication:''' Lamivudine and emtricitabine are functionally interchangeable — '''never''' combine them. Check the full medication list when reconciling ARVs (e.g., a patient on Dovato [dolutegravir/lamivudine] should not also receive Descovy [emtricitabine/TAF])
	*~~'''~~Sorbitol interaction:~~'''~~ Sorbitol-containing liquid medications significantly reduce lamivudine oral solution exposure. Avoid coadministration when possible; this is relevant in pediatric patients receiving multiple liquid formulations<ref name="EpivirPI"/>		*Sorbitol interaction: Sorbitol-containing liquid medications significantly reduce lamivudine oral solution exposure. Avoid coadministration when possible; this is relevant in pediatric patients receiving multiple liquid formulations<ref name="EpivirPI"/>
	*~~'''~~TMP-SMX interaction:~~'''~~ Trimethoprim increases lamivudine levels by ~40% via competition for renal organic cationic secretion. No dose adjustment at standard TMP-SMX doses, but ~~'''~~avoid high-dose TMP-SMX~~'''~~ (PCP treatment doses) with lamivudine when possible<ref name="EpivirPI"/>		*TMP-SMX interaction: Trimethoprim increases lamivudine levels by ~40% via competition for renal organic cationic secretion. No dose adjustment at standard TMP-SMX doses, but avoid high-dose TMP-SMX (PCP treatment doses) with lamivudine when possible<ref name="EpivirPI"/>
	*~~'''~~Low drug interaction profile:~~'''~~ Not CYP450-metabolized; does not affect levels of other drugs. Very safe from an interaction standpoint when prescribing in the ED		*Low drug interaction profile: Not CYP450-metabolized; does not affect levels of other drugs. Very safe from an interaction standpoint when prescribing in the ED
	*~~'''~~Low resistance barrier:~~'''~~ The M184V/I mutation emerges rapidly with lamivudine monotherapy or subtherapeutic dosing. This is why proper combination therapy and correct dosing (HIV vs. HBV formulation) are essential		*Low resistance barrier: The M184V/I mutation emerges rapidly with lamivudine monotherapy or subtherapeutic dosing. This is why proper combination therapy and correct dosing (HIV vs. HBV formulation) are essential
	*Overdose: No specific antidote; supportive care. No significant symptoms reported in acute overdoses. No additional dosing needed after dialysis<ref name="EpivirPI"/>		*Overdose: No specific antidote; supportive care. No significant symptoms reported in acute overdoses. No additional dosing needed after dialysis<ref name="EpivirPI"/>