Hepatitis B Virus Nucleoside Analog Reverse Transcriptase Inhibitor [EPC]
Variants
9
Drug Classes
Hepatitis B Virus Nucleoside Analog Reverse Transcriptase Inhibitor [EPC]Human Immunodeficiency Virus Nucleoside Analog Reverse Transcriptase Inhibitor [EPC]Human Immunodeficiency Virus 1 Non-Nucleoside Analog Reverse Transcriptase Inhibitor [EPC]
Key Facts
According to the FDA-approved labeling (2024), Lamivudine must be used in combination with other antiretrovirals for HIV treatment to prevent drug resistance.
A study published in the Journal of Infectious Diseases (2023) confirmed that the M184V mutation is the primary driver of lamivudine resistance in HIV-1 patients.
The World Health Organization (WHO, 2024) includes Lamivudine on its List of Essential Medicines as a core component of HIV therapy.
According to DailyMed (2024), Lamivudine has an oral bioavailability of approximately 86% in adults.
The Antiretroviral Pregnancy Registry (2023 report) found no increased risk of birth defects in over 5,000 women exposed to lamivudine during the first trimester.
Clinical data from the NIH (2024) indicates that lamivudine is primarily eliminated by the kidneys, necessitating dose adjustments for patients with a CrCl below 50 mL/min.
The FDA (2024) issues a Black Box Warning for severe Hepatitis B exacerbations in patients who discontinue lamivudine abruptly.
Research in 'Hepatology' (2022) highlighted that lamivudine remains a cost-effective option for HBV management in many global settings, despite the availability of newer agents.
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Lamivudine And Zidovudine, you must consult a qualified healthcare professional.
Detailed information about Lamivudine And Zidovudine
ℹ️Overview
Lamivudine is a potent nucleoside reverse transcriptase inhibitor (NRTI) used in the management of HIV-1 infection and chronic hepatitis B virus (HBV) infection, working by terminating viral DNA chain elongation.
💊Usage & Dosage
Adult Dosage
The dosage of lamivudine depends entirely on the condition being treated and the patient's renal function.
For HIV-1 Infection: The standard adult dose is 300 mg daily. This can be administered either as 150 mg twice daily or as 300 mg once daily. When used for HIV, it must always be used in combination with other antiretroviral medications.
For Chronic Hepatitis B: The standard adult dose is 100 mg once daily. It is critical that patients being treated for HBV are also screened for HIV, as the 100 mg dose is inadequate for HIV treatment and could lead to HIV resistance.
Pediatric Dosage
Lamivudine is approved for use in pediatric patients as young as 3 months of age for HIV and 2 years of age for HBV.
HIV-1 (Pediatric): Dosing is usually weight-based. For children weighing 14 kg to less than 20 kg, the dose is typically 150 mg daily (administered as 75 mg twice daily or 150 mg once daily). For children weighing 25 kg or more, the adult dose of 300 mg daily is generally used. For infants and smaller children, the oral solution is dosed at 4 mg/kg to 5 mg/kg twice daily.
Chronic Hepatitis B (Pediatric): For children aged 2 to 17 years, the recommended dose is 3 mg/kg once daily, up to a maximum dose of 100 mg per day.
Dosage Adjustments
Renal Impairment
Because lamivudine is primarily cleared by the kidneys, dosage adjustments are mandatory for patients with impaired renal function (Creatinine Clearance < 50 mL/min).
For HIV (300 mg standard): If CrCl is 30-49 mL/min, the dose is 150 mg once daily. If CrCl is 15-29 mL/min, the first dose is 150 mg, followed by 100 mg once daily. Further reductions are required for lower CrCl levels.
For HBV (100 mg standard): If CrCl is 30-49 mL/min, the dose is 100 mg for the first day, then 50 mg once daily. Reductions continue based on the severity of impairment.
Hepatic Impairment
No dosage adjustment is typically required for patients with hepatic impairment unless they also have concurrent renal impairment. However, liver function should be monitored closely during therapy.
Elderly Patients
Clinical studies did not include sufficient numbers of subjects aged 65 and over to determine if they respond differently. However, because elderly patients are more likely to have decreased renal function, dose selection should be cautious, and renal function should be monitored.
How to Take Lamivudine
Consistency: Take lamivudine at the same time(s) every day to maintain a steady level of the drug in your bloodstream.
Food: Lamivudine may be taken with or without food. If the oral solution is used, it should be measured with a calibrated dosing syringe or cup, not a household spoon.
Swallowing: Tablets should generally be swallowed whole. If you have difficulty swallowing, consult your pharmacist about using the oral solution or whether the tablet can be crushed and mixed with a small amount of food or liquid.
Storage: Store at room temperature (20°C to 25°C or 68°F to 77°F) in a tightly closed container.
Missed Dose
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Do not double the dose to catch up. Consistency is vital to prevent the virus from developing resistance to the medication.
Overdose
There is limited data on acute lamivudine overdose. In the event of an overdose, contact a Poison Control Center or seek emergency medical attention immediately. Treatment is generally supportive. Because lamivudine is dialyzable, continuous hemodialysis could theoretically be used, although its clinical benefit in overdose has not been fully established.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose or stop taking this medication without medical guidance, as stopping lamivudine can cause a severe 'flare-up' of Hepatitis B.
⚠️Side Effects
Common Side Effects (>1 in 10)
In clinical trials, lamivudine was generally well-tolerated, but some side effects occurred frequently, especially when used in combination with other HIV medications like zidovudine.
Nausea and Vomiting: This is often most noticeable when starting the medication and may improve as the body adjusts.
Headache: Mild to moderate headaches are common. If they become severe or persistent, notify your doctor.
Malaise and Fatigue: A general feeling of discomfort or lack of energy is frequently reported.
Nasal Symptoms: These may include a runny nose, congestion, or cough, particularly in pediatric patients.
Diarrhea: Loose stools or increased frequency of bowel movements may occur.
🔴Warnings
Important Safety Information
Before starting lamivudine, it is essential to undergo comprehensive screening. Patients must be tested for both HIV and Hepatitis B before beginning therapy with any formulation of lamivudine. This is because the treatment strategies and dosages for these two viruses differ significantly, and improper use can lead to viral resistance that limits future treatment options.
Black Box Warnings
The FDA has issued the following boxed warnings for lamivudine:
Lactic Acidosis and Hepatomegaly: There is a risk of lactic acidosis (a medical emergency caused by acid buildup in the blood) and severe hepatomegaly with steatosis (fatty liver). This risk is higher in women and obese patients.
HBV Exacerbation: If you have Hepatitis B and stop taking lamivudine, your HBV may become much worse (an 'exacerbation'). Your doctor will need to monitor your liver function for several months if you stop this medication.
🔄Interactions
Contraindicated Combinations (Do Not Use Together)
Emtricitabine (FTC): Lamivudine should not be administered concomitantly with emtricitabine-containing products (e.g., Truvada, Descovy). Emtricitabine is a structural analog of lamivudine and competes for the same intracellular phosphorylation pathways. Using both together provides no additional benefit and may increase toxicity or reduce efficacy.
Zalcitabine (ddC): Lamivudine may inhibit the intracellular phosphorylation of zalcitabine. Therefore, use of these two drugs together is not recommended.
Serious Interactions (Monitor Closely)
Trimethoprim/Sulfamethoxazole (Bactrim, Septra): This antibiotic combination can increase the plasma concentration of lamivudine by about 40% because trimethoprim interferes with the renal secretion of lamivudine. While a dose adjustment is usually not necessary for patients with normal renal function, those with renal impairment should be monitored closely for lamivudine toxicity.
🚫Contraindications
Absolute Contraindications
Hypersensitivity: Lamivudine is strictly contraindicated in patients with a known prior history of clinically significant hypersensitivity (e.g., anaphylaxis, Stevens-Johnson syndrome) to lamivudine or any of the inactive ingredients in the formulation. An allergic reaction can be life-threatening and requires immediate cessation of the drug and emergency medical care.
Co-administration with Emtricitabine: Because emtricitabine and lamivudine are functionally redundant and share the same resistance profile, their combined use is contraindicated as it offers no therapeutic advantage and increases the potential for adverse effects.
Relative Contraindications
Advanced Renal Failure (CrCl < 15 mL/min): While not an absolute contraindication, lamivudine must be used with extreme caution and significant dose reduction in these patients. If the patient is not on dialysis, the risk of drug accumulation and toxicity is very high.
👥Special Populations
Pregnancy
Lamivudine is one of the most extensively studied antiretrovirals in pregnancy.
Pregnancy Category: Formerly Category C.
Antiretroviral Pregnancy Registry (APR): Data from the APR show no significant increase in the risk of major birth defects for lamivudine compared with the background rate in the general population.
Clinical Use: It is often used to prevent mother-to-child transmission of HIV. It is generally considered a preferred NRTI for pregnant individuals living with HIV. However, it should only be used if the potential benefit justifies the potential risk to the fetus. There is no evidence of teratogenicity (causing birth defects) in human studies to date.
Breastfeeding
🧬Pharmacology
Mechanism of Action
Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI). It is a cytidine analog (2',3'-dideoxy-3'-thiacytidine). Inside the cell, it is converted by cellular deoxycytidine kinase to lamivudine monophosphate, then to the diphosphate, and finally to the active lamivudine triphosphate (L-TP).
L-TP acts in two ways:
1Competitive Inhibition: It competes with the natural substrate, deoxycytidine triphosphate (dCTP), for the active site of the viral reverse transcriptase (in HIV) or DNA polymerase (in HBV).
2Chain Termination: Once incorporated into the growing viral DNA chain, the lack of a 3'-OH group prevents the formation of the 5' to 3' phosphodiester bond required for further DNA elongation. This effectively 'breaks' the DNA synthesis process.
Frequently Asked Questions
Common questions about Lamivudine And Zidovudine
What is Lamivudine used for?
Lamivudine is a prescription antiviral medication primarily used to treat two different viral infections: Human Immunodeficiency Virus (HIV-1) and chronic Hepatitis B Virus (HBV). For HIV, it is always used in combination with other antiretroviral drugs to help control the infection and prevent the virus from damaging the immune system. For Hepatitis B, it is used to reduce the amount of HBV in the body and decrease liver inflammation. It is important to note that lamivudine does not cure these infections, but it helps manage them over the long term. Your doctor will determine the correct dose based on which condition is being treated and your kidney health.
What are the most common side effects of Lamivudine?
The most common side effects reported by patients taking lamivudine include nausea, headache, fatigue, and a general feeling of being unwell (malaise). Some people also experience diarrhea, nasal congestion, or a cough, particularly children. While many of these symptoms are mild and may improve as your body adjusts to the medicine, you should always report them to your healthcare provider. More serious but less common side effects can include muscle pain or sleep disturbances. If you experience severe stomach pain or yellowing of the skin, seek medical help immediately as these could indicate rare but serious complications.
Can I drink alcohol while taking Lamivudine?
There is no known direct chemical interaction between alcohol and lamivudine that makes the drug less effective. However, both lamivudine and excessive alcohol consumption can place stress on the liver and the pancreas. Lamivudine carries warnings regarding liver enlargement and a rare condition called pancreatitis. Drinking alcohol can increase your risk of developing these specific side effects. Therefore, most healthcare providers recommend limiting or avoiding alcohol while being treated for HIV or Hepatitis B to protect your organ function. Always discuss your alcohol consumption habits with your doctor before starting this medication.
Is Lamivudine safe during pregnancy?
Lamivudine is generally considered one of the safer antiretroviral medications to use during pregnancy and is frequently prescribed to prevent the transmission of HIV from mother to child. Large-scale data from the Antiretroviral Pregnancy Registry have shown no significant increase in birth defects compared to the general population. However, every pregnancy is unique, and the decision to use lamivudine should be made in consultation with an infectious disease specialist or an obstetrician specializing in high-risk pregnancies. It is crucial to manage viral loads during pregnancy to protect both the parent and the baby. Your doctor will weigh the benefits of viral suppression against any potential risks.
How long does it take for Lamivudine to work?
Lamivudine begins to inhibit viral replication shortly after the first few doses are taken, as it quickly reaches therapeutic levels in the blood and inside cells. However, you will not 'feel' the medication working immediately, as it does not directly treat symptoms of the infection. Instead, its effectiveness is measured through laboratory tests, such as viral load tests and CD4 cell counts. In patients with Hepatitis B, it may take several weeks or months to see a significant decrease in liver enzymes (ALT) and viral DNA levels. For HIV, the goal is to reach an 'undetectable' viral load, which typically takes a few months of consistent combination therapy.
Can I stop taking Lamivudine suddenly?
You should never stop taking lamivudine suddenly without the direct supervision of your healthcare provider. For patients with HIV, stopping the medication can allow the virus to multiply rapidly and develop resistance, making future treatments less effective. For those with Hepatitis B, stopping lamivudine can lead to a severe and dangerous 'flare-up' or exacerbation of the liver infection, which can cause liver failure. If your doctor decides you should stop the medication, they will monitor your liver function tests very closely for several months afterward. Always ensure you have an adequate supply of your medication so you do not run out.
What should I do if I miss a dose of Lamivudine?
If you miss a dose of lamivudine, you should take it as soon as you realize you have forgotten. However, if it is almost time for your next scheduled dose, you should skip the missed dose and simply take the next one at the regular time. Do not take two doses at once to make up for the one you missed, as this can increase the risk of side effects. Maintaining a consistent level of the drug in your body is critical for preventing the virus from mutating and becoming resistant. Using a pillbox or setting a daily alarm on your phone can be very helpful for staying on schedule.
Does Lamivudine cause weight gain?
Lamivudine itself is not typically associated with significant weight gain in the same way that some newer HIV medications (like certain integrase inhibitors) might be. However, many patients who start effective antiretroviral therapy for HIV experience a 'return to health' weight gain as their immune system recovers and their body begins to process nutrients more effectively. Additionally, long-term use of NRTIs like lamivudine has historically been linked to 'lipodystrophy,' which is a redistribution of body fat rather than overall weight gain. This might involve losing fat in the face and limbs while gaining it in the abdomen or neck. Discuss any concerns about body changes with your doctor.
Can Lamivudine be taken with other medications?
Lamivudine can be taken with many other medications, but there are some important exceptions. It should never be taken with emtricitabine, as they are too similar and will compete with each other. It also interacts with an antibiotic called trimethoprim (found in Bactrim), which can raise lamivudine levels in the blood. Some liquid medications containing sorbitol can also reduce how much lamivudine your body absorbs. Because lamivudine does not use the common CYP450 liver enzyme pathway, it has fewer interactions than many other drugs, but you must still provide your doctor with a full list of all supplements and medications you use.
Is Lamivudine available as a generic?
Yes, lamivudine is available as a generic medication in several strengths, including 100 mg, 150 mg, and 300 mg tablets, as well as an oral solution. Generic versions are typically much more affordable than the brand-name versions (Epivir and Epivir-HBV) and are required by the FDA to have the same active ingredient, strength, and effectiveness as the original brand. Many insurance plans prefer the use of generic lamivudine. It is also available in several generic fixed-dose combination pills, which combine lamivudine with other antiviral drugs into a single tablet to make your daily routine easier to manage.
Similar Medications
Other drugs with the same active ingredient (Lamivudine)
Abdominal Pain: Discomfort or cramping in the stomach area.
Dizziness: A sensation of spinning or lightheadedness.
Insomnia: Difficulty falling or staying asleep.
Myalgia and Arthralgia: Muscle aches and joint pain.
Fever and Chills: These may occur as part of the body's reaction to the medication or the underlying infection.
Skin Rash: Mild rashes may develop but should be monitored to ensure they do not progress to more serious reactions.
Rare Side Effects (less than 1 in 100)
Pancreatitis: Inflammation of the pancreas, which can be life-threatening. This is more common in pediatric patients with advanced HIV.
Anemia and Neutropenia: A decrease in red or white blood cells, which may cause weakness or increased risk of infection.
Peripheral Neuropathy: Tingling, numbness, or burning sensations in the hands or feet.
Alopecia: Temporary hair loss has been reported in rare instances.
Serious Side Effects — Seek Immediate Medical Attention
> Warning: Stop taking Lamivudine and call your doctor immediately if you experience any of these.
Lactic Acidosis: This is a buildup of acid in the blood. Symptoms include unusual tiredness, unexpected stomach pain, nausea, vomiting, cold feeling in arms and legs, dizziness, or fast/irregular heartbeat.
Hepatotoxicity (Liver Damage): Symptoms include yellowing of the skin or eyes (jaundice), dark urine, light-colored stools, or pain on the right side of the stomach area.
Severe Pancreatitis: Intense, persistent abdominal pain that may radiate to the back, often accompanied by vomiting.
Hypersensitivity Reactions: Swelling of the face, lips, or tongue; difficulty breathing; or severe skin blistering.
Immune Reconstitution Syndrome: In patients with HIV, the immune system may begin to respond to previously hidden infections (like pneumonia or tuberculosis), causing new inflammatory symptoms shortly after starting treatment.
Long-Term Side Effects
Lipodystrophy: Long-term use of antiretroviral therapy, including NRTIs, has been associated with the redistribution of body fat. This may include loss of fat from the legs, arms, and face, and increased fat in the abdomen, neck ('buffalo hump'), and breasts.
Bone Loss: Some patients may experience a decrease in bone mineral density over years of therapy, increasing the risk of fractures.
Renal Function Decline: While lamivudine itself is not highly nephrotoxic, long-term monitoring is required as the drug is cleared renally.
Black Box Warnings
Lamivudine carries several significant FDA Black Box Warnings that patients and providers must be aware of:
1Lactic Acidosis and Severe Hepatomegaly with Steatosis: Cases of lactic acidosis and severe liver enlargement with fat (steatosis), including fatal cases, have been reported with the use of nucleoside analogs.
2Exacerbations of Hepatitis B: In patients with both HIV and HBV, stopping lamivudine may result in a severe, acute exacerbation of Hepatitis B. Liver function must be monitored closely for several months after discontinuation.
3Different Formulations: Epivir-HBV (100 mg) is not appropriate for treating HIV. Using the lower dose in patients with undiagnosed or untreated HIV can lead to the HIV virus becoming resistant to lamivudine.
Report any unusual symptoms to your healthcare provider immediately. Early detection of side effects is key to managing your treatment safely.
HIV Resistance: Epivir-HBV tablets and oral solution contain a lower dose of lamivudine than the dose used to treat HIV infection. If you have both HIV and HBV, the 100 mg dose is not enough and will cause the HIV virus to become resistant to treatment.
Major Precautions
Pancreatitis Risk: Lamivudine should be used with extreme caution in patients with a history of pancreatitis or other risk factors for the development of pancreatitis. If symptoms like severe abdominal pain occur, the drug should be suspended until pancreatitis is ruled out.
Renal Impairment: Patients with decreased kidney function require specific dose adjustments. Failure to adjust the dose can lead to toxic levels of the drug in the body.
Fat Redistribution: Patients should be aware that their body shape may change due to fat redistribution (lipodystrophy), though the long-term health effects of these changes are not fully understood.
Immune Reconstitution Syndrome: As the immune system strengthens, it may 'overreact' to old infections. Patients should report any new symptoms of infection (fever, swelling) to their doctor immediately.
Monitoring Requirements
Regular laboratory monitoring is a critical part of lamivudine therapy:
Viral Load and CD4 Count: To ensure the HIV or HBV is being effectively suppressed.
Renal Function (Creatinine/BUN): To ensure the kidneys are clearing the drug properly and to adjust the dose if necessary.
Liver Function Tests (LFTs): To monitor for signs of hepatotoxicity or HBV flares.
Complete Blood Count (CBC): To monitor for potential bone marrow suppression (anemia or neutropenia).
Driving and Operating Machinery
Lamivudine is not generally known to cause significant sedation or cognitive impairment. However, since side effects like dizziness or fatigue can occur, patients should observe how they react to the medication before driving or operating heavy machinery.
Alcohol Use
While there is no direct chemical interaction between lamivudine and alcohol, excessive alcohol consumption can increase the risk of liver damage and pancreatitis. Since lamivudine also carries risks for these organs, it is generally advised to limit or avoid alcohol while on this medication.
Discontinuation
Never stop taking lamivudine without consulting your doctor. Abrupt discontinuation can lead to a 'rebound' of the virus. In patients with Hepatitis B, stopping the drug can cause severe liver inflammation. If discontinuation is necessary, your healthcare provider will likely monitor your liver enzymes (ALT/AST) for several months afterward.
> Important: Discuss all your medical conditions, especially kidney disease, liver disease, or pancreatitis, with your healthcare provider before starting Lamivudine.
Sorbitol: Co-administration of single doses of lamivudine and sorbitol (often found in other liquid medications) has been shown to result in a dose-dependent decrease in lamivudine exposure. When possible, avoid chronic co-administration of lamivudine with sorbitol-containing medicines.
Moderate Interactions
Interferon-alpha and Ribavirin: Patients receiving lamivudine along with interferon-alpha and ribavirin for Hepatitis C (HCV) co-infection should be monitored for hepatic decompensation and other toxicities, as these drugs can have overlapping side effect profiles on the liver.
Other NRTIs: While lamivudine is often used with other NRTIs (like zidovudine or abacavir), the specific combination must be chosen carefully by an HIV specialist to avoid antagonistic effects or cumulative mitochondrial toxicity.
Food Interactions
High-Fat Meals: While food does not significantly decrease the total absorption (AUC) of lamivudine, a high-fat meal can delay the time it takes to reach peak levels (Tmax). This is generally not clinically significant, and lamivudine can be taken with or without food.
Alcohol: As mentioned previously, alcohol does not change the drug's metabolism but can increase the risk of liver and pancreas complications.
Herbal/Supplement Interactions
St. John's Wort: While St. John's Wort is a potent inducer of CYP3A4, lamivudine is not metabolized by this enzyme. However, St. John's Wort can lower the levels of other antiretrovirals often taken with lamivudine, potentially leading to treatment failure. Always consult your doctor before using herbal supplements.
Milk Thistle: Some patients use milk thistle for liver health; however, its interaction with lamivudine's renal clearance has not been extensively studied.
Lab Test Interactions
Amylase/Lipase: Lamivudine can cause elevations in these enzymes, which might be misinterpreted as pancreatitis. Clinical correlation is required.
Liver Enzymes (ALT/AST): Elevations may occur during treatment or as a 'flare' if the drug is discontinued.
For each major interaction, the mechanism typically involves either renal clearance competition (as with trimethoprim) or intracellular phosphorylation competition (as with emtricitabine). The clinical consequence is usually an increased risk of side effects or a reduction in the drug's ability to suppress the virus.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter cough syrups which may contain sorbitol.
Active Pancreatitis: In patients with active, acute pancreatitis, lamivudine should be avoided unless the benefits of treating the underlying viral infection clearly outweigh the risk of worsening the pancreatic inflammation.
Severe Hepatic Decompensation: In patients with 'end-stage' liver disease, the risk of lactic acidosis may be higher, requiring very close clinical monitoring.
Cross-Sensitivity
Other Nucleoside Analogs: While there is no definitive evidence of broad cross-allergenicity between all NRTIs, patients who have had severe skin reactions to other nucleoside analogs (like abacavir or tenofovir) should be monitored closely when starting lamivudine, although the chemical structures are distinct.
> Important: Your healthcare provider will evaluate your complete medical history, including any previous drug allergies and your current kidney and liver status, before prescribing Lamivudine.
HIV-Infected Mothers: In the United States and other regions where safe infant formula and clean water are available, the CDC and major medical associations recommend that HIV-infected mothers not breastfeed their infants. This is to avoid the risk of postnatal transmission of HIV through breast milk.
Drug Passage: Lamivudine is excreted in human breast milk. While the concentration in the infant's blood is low, the risk of the infant developing viral resistance or side effects exists.
Pediatric Use
Approval: Lamivudine is approved for HIV treatment in infants as young as 3 months and for HBV in children 2 years and older.
Considerations: Pediatric patients, especially those with advanced HIV, are at a higher risk for developing pancreatitis. Close monitoring of symptoms and amylase/lipase levels is necessary. The oral solution is preferred for children who cannot swallow tablets to ensure accurate weight-based dosing.
Geriatric Use
Renal Function: The most significant concern in elderly patients is the natural decline in glomerular filtration rate (GFR). Since lamivudine is renally excreted, many elderly patients will require a lower dose.
Polypharmacy: Older adults are often taking multiple medications for blood pressure, diabetes, or heart disease. While lamivudine has few CYP450 interactions, the risk of overlapping toxicities (like kidney strain) must be considered.
Renal Impairment
As previously detailed, the kidneys are the primary exit route for lamivudine. In patients with a GFR or CrCl below 50 mL/min, the standard dose will lead to excessively high blood levels.
Dialysis: Lamivudine is removed by hemodialysis. For patients on hemodialysis, the dose is usually adjusted to once-daily administration after the dialysis session.
Hepatic Impairment
Lamivudine has been studied in patients with various degrees of hepatic impairment. Because the liver is not the primary route of elimination, the pharmacokinetics are not significantly altered. However, the risk of lactic acidosis and the potential for HBV flares upon discontinuation mean these patients require specialized care by a hepatologist or infectious disease specialist.
> Important: Special populations require individualized medical assessment and frequent laboratory follow-up to ensure safety and efficacy.
Pharmacodynamics
The relationship between lamivudine plasma concentration and its antiviral effect is complex because the active form is intracellular. The antiviral activity is dose-dependent up to a certain threshold. Resistance typically emerges through specific mutations in the viral genome, most notably the M184V mutation in HIV reverse transcriptase and the M204V/I mutation in the HBV YMDD motif.
| Metabolism | Minimal (< 5% to trans-sulfoxide) |
| Excretion | Renal (70% unchanged via tubular secretion) |
Chemical Information
Molecular Formula: C8H11N3O3S
Molecular Weight: 229.26 g/mol
Solubility: Highly soluble in water (~70 mg/mL at 20°C).
Structure: It is the negative enantiomer of a 2'-deoxy-3'-thiacytidine, a pyrimidine nucleoside analog where the 3' carbon is replaced by a sulfur atom.
Drug Class
Lamivudine is categorized as a Nucleoside Reverse Transcriptase Inhibitor (NRTI). It is closely related to other NRTIs such as emtricitabine, abacavir, tenofovir, and zidovudine. In the context of HBV, it is considered a nucleoside analog polymerase inhibitor.