Common uses of Epivir (lamivudine)
Epivir is a nucleoside reverse transcriptase inhibitor (NRTI) used primarily to treat HIV-1 infection as part of a combination antiretroviral regimen. It helps lower viral load, raise CD4 counts, and reduce the risk of HIV-related complications when taken consistently with other agents.
Lamivudine is also used to treat chronic hepatitis B virus (HBV) infection, marketed at a different dose as Epivir-HBV. While effective, lamivudine monotherapy for HBV is prone to resistance; current HBV guidelines often prefer tenofovir or entecavir. In people with HIV/HBV coinfection, Epivir should not be used alone—pair it with a second HBV-active drug (e.g., tenofovir) as part of a complete HIV regimen to prevent resistance and HBV flares.
Epivir dosage and directions
For HIV-1 in adults and adolescents: the usual Epivir dose is 300 mg once daily or 150 mg twice daily, always in combination with other antiretrovirals. Consistency is critical; missed or irregular dosing can lead to viral rebound and resistance (notably the M184V mutation).
For chronic HBV (Epivir-HBV): typical adult dosing is 100 mg once daily. Because resistance develops readily with lamivudine monotherapy, clinicians often reserve its use for specific scenarios or when other agents are not suitable. Never switch or stop HBV therapy abruptly without medical guidance due to risk of severe hepatitis flares.
Renal impairment: lamivudine is renally cleared and requires dose adjustment when creatinine clearance (CrCl) is below 50 mL/min. Clinicians often use the oral solution (10 mg/mL) to fine-tune reduced doses. If you are on dialysis or have chronic kidney disease, ask your prescriber for an individualized regimen.
Pediatrics: dosing is weight-based using the oral solution or pediatric-friendly tablets to reach a total daily dose up to the adult maximum (commonly 8 mg/kg/day up to 300 mg/day for HIV). Because pancreatitis risk is higher in children, especially those with a history of pancreatitis, monitoring is more vigilant in pediatric patients.
Administration tips: Epivir may be taken with or without food. If prescribed the oral solution, use an accurate dosing syringe. Avoid sorbitol-containing liquid excipients when possible, as sorbitol can reduce lamivudine exposure.
Precautions and warnings
Black box warning: NRTIs, including lamivudine, have been associated with rare but serious lactic acidosis and severe hepatomegaly with steatosis. Seek urgent care for deep, persistent fatigue, abdominal pain, rapid breathing, or sudden nausea/vomiting.
HBV flares: If you have HBV and stop Epivir suddenly, you can experience a serious hepatitis flare. Your clinician will monitor liver enzymes closely for several months after discontinuation and will plan any switches to a fully HBV-active regimen to minimize risk.
Not for HIV monotherapy: Epivir must be used in combination with other antiretrovirals. Using it alone (or functionally alone, e.g., with interactions lowering exposure) risks rapid resistance and treatment failure.
Pancreatitis risk: Pancreatitis has been reported, particularly in pediatric patients. Stop the drug and contact your clinician immediately if you develop severe, persistent abdominal pain, back pain, nausea, or vomiting.
Immune reconstitution: Starting effective HIV therapy can unmask underlying infections (immune reconstitution inflammatory syndrome). Report new or worsening symptoms after initiating therapy.
Pregnancy and breastfeeding: Lamivudine has extensive pregnancy experience and is commonly used when clinically indicated. It passes into breast milk. In the U.S., people with HIV are advised not to breastfeed to prevent postnatal transmission. Discuss benefits and risks with your clinician if you are pregnant or nursing.
Renal impairment: Dose adjustments are required; ensure your prescriber knows your kidney function and other medications that may affect renal elimination.
Contraindications
Epivir is contraindicated in patients with known hypersensitivity to lamivudine or any component of the formulation. Do not use Epivir as monotherapy for HIV. Avoid duplication with other lamivudine-containing products or with emtricitabine (which has overlapping activity) unless specifically directed by a specialist to avoid therapeutic redundancy.
Possible Epivir side effects
Common side effects are usually mild and may include headache, nausea, diarrhea, fatigue, nasal symptoms, cough, and insomnia. Many people tolerate Epivir well over the long term.
Less common side effects include abdominal pain, vomiting, dizziness, rash, and elevated liver enzymes. Hematologic effects (like neutropenia or anemia) are less frequent with lamivudine than with older agents but can occur, particularly when combined with zidovudine.
Serious side effects are uncommon but require prompt medical attention: lactic acidosis, severe hepatomegaly with steatosis, pancreatitis (especially in children or those with a prior history), severe rash, or signs of liver inflammation (jaundice, dark urine, right upper quadrant pain). In people with HIV/HBV coinfection, watch for hepatitis flares if therapy is altered or interrupted.
If you develop unusual muscle pain, profound weakness, rapid breathing, persistent vomiting, or marked abdominal tenderness, stop Epivir and contact your clinician or emergency services.
Epivir drug interactions
Lamivudine has a low potential for cytochrome P450 interactions. Key interactions include:
• Sorbitol (found in some liquid medications) can reduce lamivudine exposure; avoid or minimize sorbitol-containing products, especially in children, or consider monitoring levels and clinical response.
• Trimethoprim/sulfamethoxazole can increase lamivudine concentrations; dose adjustments are usually not required in those with normal renal function, but closer monitoring is warranted if kidney function is reduced.
• Do not coadminister with emtricitabine or duplicate lamivudine-containing products due to overlapping activity with no added benefit.
• Avoid the discontinued NRTI zalcitabine (ddC) if encountered in legacy regimens due to antagonism with lamivudine.
Always provide your clinician and pharmacist with a complete list of prescription drugs, OTC products, herbal supplements, and any liquid medicines that might contain sorbitol or other sugar alcohols.
Missed dose
If you miss a dose of Epivir, take it as soon as you remember, unless it is near the time of your next dose. In that case, skip the missed dose and resume your regular schedule. Do not double up. Consistent adherence is essential for HIV control; consider reminders, pill boxes, or smartphone apps to help stay on track.
Overdose
Accidental overdose is uncommon; symptoms may include nausea, vomiting, dizziness, or fatigue. Seek immediate medical attention or contact Poison Control at 1-800-222-1222 (U.S.). Supportive care is standard; lamivudine is dialyzable to some extent, which may be considered in severe cases or significant renal impairment under medical supervision.
Storage
Store Epivir tablets and oral solution at room temperature, protected from excessive heat and moisture. Keep the bottle tightly closed and out of reach of children and pets. Do not use after the expiration date. If using the oral solution, measure doses with an accurate oral syringe, not a kitchen spoon.
U.S. sale and prescription policy for Epivir
Epivir (lamivudine) is a prescription-only medication in the United States. Federal and state regulations require a valid prescription from a licensed clinician; any website offering Epivir without a prescription should be avoided due to safety, quality, and legal concerns. Use state-licensed pharmacies and verify legitimacy (e.g., NABP .pharmacy or LegitScript).
HealthSouth Rehabilitation Hospital of Las Vegas and other reputable services can help you access Epivir through lawful, structured pathways—either by filling an existing prescription or by arranging a telehealth visit with a licensed clinician who can evaluate you and, if appropriate, prescribe Epivir as part of a complete treatment plan. Discuss insurance coverage, generic lamivudine pricing, manufacturer assistance, or 340B/clinic programs to improve affordability. Never start, stop, or switch antiretrovirals without medical guidance.
