Lamivudine
A cytidine analog NRTI used with other antiretrovirals for HIV, and in a lower-dose product for chronic hepatitis B.
Also called 3TC (abbreviation).
Drug card
- How it works
- Ending the viral DNA chain as false nucleotides for reverse transcriptase
- Used for
- HIV-1 infection, with other antiretrovirals
- Chronic hepatitis B (lower-dose product)
- Known for
- Severe hepatitis B flare when stopped
- Its name
- -vudine means a nucleoside antiviral (zidovudine type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does lamivudine work?
Cell kinases turn it into lamivudine triphosphate, which HIV reverse transcriptase builds into viral DNA, ending the chain; it ends hepatitis B DNA chains the same way. It only weakly inhibits human DNA polymerases. A single reverse transcriptase mutation, M184V or M184I, makes HIV resistant.
Like other nucleoside reverse transcriptase inhibitors: NRTIs are nucleoside or nucleotide look-alikes. Cell kinases phosphorylate them to their active forms, which compete with natural nucleotides at the active site of HIV reverse transcriptase. Once built into the viral DNA copy they end the chain, so HIV cannot make DNA from its RNA. Some also block the hepatitis B polymerase, and they weakly inhibit human DNA polymerases.
Uses
What is lamivudine used for?
- HIV-1 infection, with other antiretrovirals
- Chronic hepatitis B (lower-dose product)
Side effects
Side effects of lamivudine
- Severe hepatitis B flare when stoppedKnown forSerious
- Headache
- Nausea
- Diarrhea
- Tiredness and malaise
- Lactic acidosis with fatty, enlarged liverSerious
- Pancreatitis, mainly in children at riskSerious
- Anemia, including pure red cell aplasiaSerious
- High blood sugar
- Muscle weakness and rhabdomyolysisSerious
- Hair loss
- Body fat redistribution
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Stopping it in hepatitis B co-infection can cause a severe flare, so liver tests continue for months.
- HIV needs the full HIV dose: the lower hepatitis B product would let HIV resistance emerge fast.
- Adjust the dose in kidney impairment.
Good to know: HIV becomes resistant through a single reverse transcriptase mutation, M184V or M184I, so it must always be combined with other antiretrovirals.
Remember it
A way to remember it
NRTIs are fake bricks: the wall of viral DNA stops where they are laid.
Reverse transcriptase picks up the false nucleotide and builds it into the DNA copy of HIV's RNA, and no further bricks can be added: chain termination.
Written for biofideX
Its name
-vudine means nucleoside antiviral (zidovudine type)
Zidovudine and lamivudine block HIV reverse transcriptase, and lamivudine also treats hepatitis B. WHO files -vudine under -uridine.
- Every drug name stem
Its class
Nucleoside reverse transcriptase inhibitors
Other nucleoside reverse transcriptase inhibitors with a card:
Easily mixed up with non-nucleoside reverse transcriptase inhibitors and antiherpes nucleoside analogues.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Antivirals
Lamivudine is one of 10 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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