Indications 

Zeffix is an oral medication primarily indicated for the treatment of chronic hepatitis B virus (HBV) infection in adults and children aged 2 years and older. It is specifically used in adults with compensated liver disease and evidence of active viral replication 

Zeffix contains the active substance lamivudine. It belongs to a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs), which interfere with the process of viral replication. Zeffix works by inhibiting the replication of the hepatitis B virus (HBV) and reducing the viral load in the body.  

Use and Dosage 

Take Zeffix tablets exactly as prescribed by your healthcare provider. The Zeffix is available in the form of 100 mg tablets usually taken orally with water. Swallow the tablets whole and do not crush or chew them, unless otherwise instructed by your healthcare provider.  

The recommended dosage may vary depending on individual factors such as the severity of your condition and your response to treatment. However, the usual and most common recommended dosages is to take 100 mg tablet once a day with or without food. Take the tablet consistently and at the same time each day. This helps maintain a steady level of the medication in your body. 

If you miss a dose of Zeffix, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. 

Side Effects 

Common Side Effects  

• Depression 
• Diarrhea 
• Difficulty falling sleeping or staying asleep 
• Headache 
• Stuffy nose 

Serious Side Effects  

• Burning in the fingers or toes 
• Dark yellow or brown urine 
• Dizziness or lightheadedness 
• Excessive tiredness 
• Fast or irregular heartbeat 
• Flu-like symptoms such as fever, chills, or cough; or feeling cold, especially in the arms or legs 
• Light-colored bowel movements 
• Loss of appetite 
• Muscle pain 
• Nausea (in children) 
• Numbness 
• Ongoing pain that begins in the stomach area but may spread to the back (in children) 
• Pain in the upper right part of stomach 
• Rash 
• Shortness of breath or difficulty breathing 
• Stomach pain with nausea 
• Tingling 
• Unusual bleeding or bruising 
• Vomiting 
• Vomiting (in children) 
• Weakness 
• Yellowing of the skin or eyes 

Cautions 

• Allergic reactions: Like any medication, Zeffix can potentially cause allergic reactions. Signs of an allergic reaction may include rash, itching, swelling, dizziness, and difficulty breathing. If any allergic symptoms occur, seek immediate medical attention. 
• Drug interactions: Lamivudine may interact with other medications, including prescription, non-prescription drugs, and herbal supplements. Inform your healthcare provider about all the medications and supplements you are taking to avoid potential interactions. 
• Hepatic impairment: Zeffix should be used with caution in individuals with pre-existing liver disease or hepatic impairment, as it may require dosage adjustments or additional monitoring. 
• Hepatitis B resistance: Zeffix may lead to the development of resistance to lamivudine in individuals with hepatitis B. regular monitoring of liver function and viral load is necessary to assess the effectiveness of the treatment. 
• HIV co-infection: If an individual with hepatitis B is also co-infected with HIV, consider the potential for developing resistance to both lamivudine and other HIV medications. Close monitoring and appropriate management may be necessary. 
• Immune reconstitution syndrome: In individuals with HIV and hepatitis B co-infection who start Zeffix, there is a risk of developing immune reconstitution syndrome. It is a condition where the immune system becomes more active, potentially causing inflammation and worsening of symptoms. Be aware of this possibility and promptly report any new or worsening symptoms to a healthcare professional. 
• Lactic acidosis: There is a risk of lactic acidosis, a serious condition that can occur with the use of nucleoside analogues like lamivudine. Symptoms of lactic acidosis may include weakness, muscle pain, difficulty breathing, abdominal pain, and nausea. If any of these symptoms occur, seek medical attention immediately. 
• Pancreatitis: In rare cases, lamivudine has been associated with pancreatitis, which is inflammation of the pancreas. Symptoms may include severe abdominal pain, nausea, and vomiting. If these symptoms occur, prompt medical attention is necessary. 
• Pregnancy and breastfeeding: The use of Zeffix during pregnancy and breastfeeding should be carefully considered.  
• Renal impairment: Zeffix is primarily eliminated from the body through the kidneys. Therefore, individuals with impaired renal function may require dose adjustments or closer monitoring to ensure the medication is being appropriately cleared from the body.