chemistry

Lamivudine

Lamivudine is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lamivudine rather than just read about it. In short: Lamivudine, commonly called 3TC, is an antiretroviral medication used to prevent and treat HIV/AIDS. It is also used to treat chronic hepatitis B when other options are not possible.

Key takeaways

Lamivudine belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lamivudine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lamivudine from memory before moving on to harder problems.

Reference excerpt

Lamivudine, commonly called 3TC, is an antiretroviral medication used to prevent and treat HIV/AIDS. It is also used to treat chronic hepatitis B when other options are not possible. It is effective against both HIV-1 and HIV-2. It is typically used in combination with other antiretrovirals such as zidovudine, dolutegravir, and abacavir. Lamivudine may be included as part of post-exposure prevention in those who have been potentially exposed to HIV. Lamivudine is taken by mouth as a liquid or tablet. Common side effects include nausea, diarrhea, headaches, feeling tired, and cough. Serious side effects include liver disease, lactic acidosis, and worsening hepatitis B among those already infected. It is safe for people over three months of age and can be used during pregnancy. The medication can be taken with or without food. Lamivudine is a nucleoside reverse transcriptase inhibitor and works by blocking the HIV reverse transcriptase and hepatitis B virus polymerase. Lamivudine was patented in 1995 and approved for use in the United States in 1995. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication.

Medical uses Lamivudine (Epivir) is indicated in combination with other antiretroviral agents for the treatment of HIV‑1 infection. Lamivudine (Epivir HBV) is indicated for the treatment of chronic hepatitis B virus infection associated with evidence of hepatitis B viral replication and active liver inflammation. Lamivudine has been used for treatment of chronic hepatitis B at a lower dose than for treatment of HIV/AIDS. It improves the seroconversion of e-antigen positive hepatitis B and also improves histology staging of the liver. Long-term use of lamivudine leads to emergence of a resistant hepatitis B virus (YMDD) mutant. Despite this, lamivudine is still used widely as it is well tolerated.

Resistance

In HIV, high level resistance is associated with the M184V/I mutation in the reverse transcriptase gene as reported by Raymond Schinazi's group at Emory University. GlaxoSmithKline claimed that the M184V mutation reduces "viral fitness", because of the finding that continued lamivudine treatment causes the HIV viral load to rebound but at a much lower level, and that withdrawal of lamivudine results in a higher viral load rebound with rapid loss of the M184V mutation; GSK therefore argued that there may be benefit in continuing lamivudine treatment even in the presence of high level resistance, because the resistant virus is "less fit". The COLATE study has suggested that there is no benefit to continuing lamivudine treatment in patients with lamivudine resistance. In hepatitis B, lamivudine resistance was first described in the YMDD (tyrosine-methionine-aspartate-aspartate) locus of the HBV reverse transcriptase gene. The HBV reverse transcriptase gene is 344 amino acids long and occupies codons 349 to 692 on the viral genome. The most commonly encountered resistance mutations are M204V/I/S. The change in amino acid sequence from YMDD to YIDD results in a 3.2 fold reduction in the error rate of the reverse transcriptase, which correlates with a significant growth disadvantage of the virus. Other resistance mutations are L80V/I, V173L and L180M.

Side effects

Minor side effects may include nausea, fatigue, headaches, diarrhea, cough and nasal congestion. Do not prescribe lamivudine/zidovudine, abacavir/lamivudine, or abacavir/lamivudine/zidovudine to patients taking emtricitabine. Long-term use of lamivudine can trigger a resistant hepatitis B virus (YMDD) mutant. HIV or HBV-infected women on lamivudine are warned to discontinue breastfeeding as this puts the baby at risk for HIV transmission and medication side effects. Patients who are infected with HIV and HCV and are on both interferon and lamivudine can experience liver damage. The drug can trigger an inflammatory response to opportunistic infections (e.g., Mycobacterium avium complex [MAC], M. tuberculosis, cytomegalovirus [CMV], Pneumocystis jirovecii [formerly P. carinii). Autoimmune disorders have been reported and symptoms can occur many months after initiation of the antiretroviral therapy. Use with caution for patients with impaired renal function and do not prescribe this treatment to patients with impaired liver function.

Mechanism of action Lamivudine is an analogue of cytidine. It can inhibit both types (1 and 2) of HIV reverse transcriptase and also the reverse transcriptase of hepatitis B virus. It is phosphorylated to active metabolites that compete for incorporation into viral DNA. They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis. The lack of a 3'-OH group in the incorporated nucleoside analogue prevents the formation of the 5' to 3' phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated. Lamivudine is administered by mouth, and it is rapidly absorbed with a bio-availability of over 80%. Some research suggests that lamivudine can cross the blood–brain barrier. Lamivudine is often given in combination with zidovudine, with which it is highly synergistic. Lamivudine treatment has been shown to restore zidovudine sensitivity of previously resistant HIV. Lamivudine showed no evidence of carcinogenicity or mutagenicity in in vivo studies in mice and rats at doses from 10 to 58 times those used in humans. It has a half-life of 5–7 hours in adults and 2 hours in children.

History Racemic BCH-189 (the minus form is known as lamivudine) was invented by Bernard Belleau while at work at McGill University and Paul Nguyen-Ba at the Montreal-based IAF BioChem International, Inc. laboratories in 1988 and the minus enantiomer isolated in 1989. Samples were first sent to Yung-Chi Cheng of Yale University for study of its toxicity. When used in combination with AZT, he discovered that lamivudine's negative form reduced side effects and increased the drug's efficiency at inhibiting reverse transcriptase. The combination of lamivudine and AZT increased the efficiency at inhibiting an enzyme HIV uses to reproduce its genetic material. As a result, lamivudine was identified as a less toxic agent to mitochondria DNA than other retroviral drugs. Lamivudine was approved by the US Food and Drug Administration (FDA) in November 1995, for use with zidovudine (AZT) and again in 2002. It is on the World Health Organization's List of Essential Medicines.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Lamivudine

Start with the simplest possible case. Write down what Lamivudine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lamivudine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lamivudine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lamivudine

In research: Lamivudine appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lamivudine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lamivudine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Drugs developed by GSK plc, Hepatotoxins, Hydroxymethyl compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Lamivudine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Lamivudine” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Lamivudine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lamivudine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lamivudine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lamivudine in simple terms?

Lamivudine, commonly called 3TC, is an antiretroviral medication used to prevent and treat HIV/AIDS. It is also used to treat chronic hepatitis B when other options are not possible.

Why does Lamivudine matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lamivudine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lamivudine.