Lamivudine (Oral)


Also known as 3TC, Lamivudine is used to treat patients who have contracted the human immunodeficiency virus (HIV) or patients who have developed acquired immune deficiency syndrome (AIDS). Although Lamivudine is not a cure for HIV or AIDS, it does inhibit HIV reverse transcriptase. In doing so, it makes elongation of the DNA chain impossible and viral DNA growth is, therefore, prevented.

As the virus is no longer able to replicate itself, the patient's viral load is not increased. The viral load refers to how much HIV is present in the patient's system. By keeping the patient's viral load as low as possible, their symptoms are reduced and the risk of complications arising from HIV is reduced. By limiting the ability of the virus to replicate and increase the patient's load, Lamivudine prevents the virus from destroying the patient's immune system at the same rate.

Effective against both HIV-1 and HIV-2, Lamivudine is the first-line treatment for patients with HIV or AIDS. In most cases, however, Lamivudine is used alongside other medications, such as Abacavir and Zidovudine. When these medications are effective, HIV is less able to cause damage to the immune system. As a result, the patient is less prone to infections and illnesses, which often occur because of complications arising from the virus.

Although Lamivudine is not a cure for HIV, it can be used prophylactically if patients have been exposed to the virus. While medication cannot guarantee that HIV won't be contracted, it can significantly reduce the chance of the patient developing HIV after they have been exposed to the virus.

As well as being used to treat HIV, Lamivudine can be prescribed to patients who have a hepatitis B infection. However, Lamivudine is usually prescribed in lower doses when treating hepatitis B infections when compared to the standard treatment protocol for HIV.

In the majority of instances, however, Lamivudine is used as part of a treatment regime for patients who have already been diagnosed with HIV or AIDS. While the medication does carry some risks and can cause a range of side-effects, it is effective in reducing the amount of HIV in the patient's system. As a result, Lamivudine is often associated with improving the patient's length and quality of life, despite the possibility of adverse effects occurring.

Conditions Treated

  • Human immunodeficiency virus (HIV)
  • Acquired immune deficiency syndrome (AIDS)
  • Hepatitis B infection

Type Of Medicine

  • Antiretroviral

Side Effects

While side-effects can occur when taking any type of medication, antiretroviral drugs, such as Lamivudine, are associated with a number of adverse effects. Some of these may be more apparent when patients first start taking the medication, but may diminish over time.

For example, when patients are taking Lamivudine, they may develop the following side effects:

  • Sour or acid stomach
  • Joint or muscle pain
  • Belching
  • Numbness, tingling, pain or burning in the feet, legs, hands or arms
  • Depression
  • Sensation of 'Ĺ“pins and needles'
  • General feeling of discomfort or illness
  • Sore throat
  • Headache
  • Stabbing pain
  • Heartburn
  • Stomach upset, pain or discomfort
  • Indigestion
  • Runny or stuffy nose
  • Increased thirst
  • Trouble sleeping
  • Dry mouth
  • Weight loss (may be unexplained)
  • Sweating
  • Blurred vision
  • Pale skin
  • Dry, flushed skin
  • Increased urination
  • Weight gain around the upper back, face, waist, breasts or neck
  • Fruit-like breath odor
  • Trouble breathing with exertion
  • Increased hunger
  • Thinning of the hair or hair loss

Although the above side-effects will not necessarily warrant medical attention, patients should seek medical help if they are severe, prolonged or troublesome. In many cases, doctors can provide advice regarding the management of side effects and may be able to prescribe additional medication to reduce particularly serious side effects.

If patients experience the following adverse effects when taking Lamivudine, they should seek immediate medical advice:

  • Stomach or abdominal discomfort
  • Fever
  • Tarry, black stools
  • Shallow, fast breathing
  • Bleeding gums
  • Fast heartbeat
  • Bloating
  • Dizziness
  • Blood in the stools or urine
  • General feeling of discomfort
  • Chills
  • General feeling of weakness or tiredness
  • Constipation
  • Indigestions
  • Cough
  • Red pinpoint spots on the skin
  • Darkened urine
  • Nausea and vomiting
  • Decreased appetite
  • Muscle stiffness or pain
  • Diarrhea
  • Muscle spasms or cramps
  • Difficulty with swallowing
  • Loss of appetite
  • Pains in the side, abdomen or stomach, may radiate to the back
  • Light-colored stools
  • Swelling or puffiness around the face, tongue, lips, eyes or of the eyelids
  • Unusual weakness or tiredness
  • Right upper abdominal or stomach fullness and pain
  • Unusual bruising or bleeding
  • Hives or itching
  • Yellowing of the skin or eyes
  • Sleepiness
  • Pain in the stomach or upper right part of the abdomen
  • Rash on the skin
  • Tightness in the chest

When taking Lamivudine, patients should also seek medical help if they experience any side-effects which are not listed above.


If patients are prescribed Lamivudine for the treatment of HIV or AIDS, they are usually advised to take 300mg once per day or 150mg twice per day. However, this dose of medication is only usually given to patients who are over the age of seventeen years. For patients between the ages of three months and sixteen years, the dose is dependent on their weight. If the patient weighs over 14kg, they are usually prescribed Lamivudine in tablet form and instructed to take between 150mg-300mg per day. However, if the patient weighs less than this, they are likely to be prescribed Lamivudine as a solution and instructed to use 8mg per kilogram of body weight, once per day. Alternatively, 4mg of Lamivudine solution per kilogram of body weight can be administered twice per day.

When adult patients are given Lamivudine to treat a hepatitis B infection, they are generally instructed to take 100mg per day. If the patient is aged between two and seventeen years, they will usually be prescribed 3mg of Lamivudine per kilogram of bodyweight, to be taken once per day.

Although this is a standard treatment regime, patients should follow the instructions given to them by their doctor. Their dose of Lamivudine may be modified depending on their age, weight, current presentation, medical history and other medications.

Patients should continue to take Lamivudine as instructed by their doctor, even if their symptoms improve or if they feel well. If patients are taking Lamivudine for the treatment of HIV or AIDS, they are usually prescribed the medication on a long-term basis and should continue to take it in accordance with their treatment regime. Patients should obtain an additional supply of medication when theirs runs low so that they do not risk running out of Lamivudine and missing a dose of medicine.

There is more than one type brand of Lamivudine and they are generally used for different purposes. One brand is predominantly used to treat patients with HIV, whilst the other is used to treat hepatitis B infections. As each brand contains different amounts of Lamivudine, patients should only use the brand prescribed to them by their doctor. When the patient obtains additional prescriptions for Lamivudine, they should ensure that they have been given the correct brand of Lamivudine.

If patients are prescribed Lamivudine in solution form, a measuring spoon, medical spoon or medical syringe should be used to measure their dose accurately. Household spoons are unlikely to give an accurate measurement and should not be used to administer medication.

When taking Lamivudine, it's important that patient's stick to a strict treatment regime, particularly if they are taking other medications at the same time. However, if patients forget to take a dose of Lamivudine, they should do so as soon as they remember to. If their next dose of medicine is almost due, patients should skip the missed dose. It is not appropriate for patients to take a double dose of Lamivudine, even if they have missed a previous dose.

If patients are unsure when to take Lamivudine or how to take this medicine, they should contact their physician or pharmacist for advice.

Potential Drug Interactions

As some medicines can interact with one another, patients should tell their doctor if they are taking any other medicines, supplements or vitamins before they start using Lamivudine. Taking the following medicines in conjunction with Lamivudine is not usually advisable:

  • Orlistat
  • Dasabuvir

In some instances, however, taking Lamivudine alongside one of the medications listed above may be in the patient's best interests. If so, their dose may be altered in order to try and prevent a drug interaction occurring.

Once patients have started to take Lamivudine, they should obtain medical advice before taking any new medicines, vitamins or supplements in case they interact with their existing medication.


Before patients begin taking Lamivudine, they should discuss their existing health problems and medical history with their physician. There are some conditions which may affect the use of Lamivudine and these include:

Pediatric patients may be prescribed Lamivudine for the purposes of managing HIV. However, the safety of this medication has not been confirmed in relation to patients under the age of three months. Due to this, patients under this age are unlikely to be prescribed Lamivudine for the treatment of HIV.

Similarly, pediatric patients may be prescribed Lamivudine to treat a hepatitis B infection. The use of Lamivudine in treating this condition has not been tested on patients under the age of two years. Due to this, infants under this age with a hepatitis B infection are unlikely to be treated with this medication.

Geriatric patients may be prescribed Lamivudine but their dose may need to be lowered, in some cases. As older patients are more likely to have age-related kidney, heart or liver problems, it may take longer for their body's to process the medication. By reducing their dose of Lamivudine, physicians can prevent the medication from building up to a toxic level. Once the patient's response to Lamivudine has been assessed, their dose may be increased accordingly.

When patients are taking Lamivudine, they will need to have regular consultations with their physician. This will enable their doctor to determine how effective the patient's treatment is, make necessary changes to their dose of medication and ensure that the medicine isn't having any unwanted effected.

Lamivudine can sometimes cause two serious health complications; liver toxicity and/or lactic acidosis. Although these conditions are both rare, they are more common in patients who are female, obese and those who have been taking anti-HIV medications for a significant period of time. If patients exhibit any of the following symptoms when taking Lamivudine, they should obtain immediate medical treatment:

  • Stomach cramping or discomfort
  • Diarrhea
  • Nausea or vomiting
  • General feeling of discomfort
  • Decreased appetite
  • Trouble breathing
  • Muscle pain or camping
  • Yellowing of the skin or eyes
  • Unusual weakness or tiredness

When treatment with Lamivudine is discontinued, it may cause a hepatitis B infection to worsen in some cases.

In some patients, Lamivudine can cause pancreatitis. If patients develop the following symptoms when taking this medication, they should access urgent medical help:

  • Lightheadedness
  • Fever
  • Chills
  • Vomiting
  • Constipation
  • Severe and sudden stomach pain

When patients are taking Lamivudine, their immune system should become stronger. However, this could cause an existing infection to become active. If patients feel unwell or develop symptoms associated with an infection, they should contact their physician and/or seek medical help.

Taking Lamivudine can cause an increase in the amount of body fat a patient has. Patients should inform their doctor straight away if they notice the following changes:

  • Increased amount of body fat around the neck or face
  • Increased amount of body fat around the stomach, chest or upper back
  • Loss of fat from the face, arms or legs

Although Lamivudine can be used to manage HIV and to reduce the patient's viral load, it is still possible for patients to transmit the virus to other individuals. HIV is transmitted via sexual contact and/or the contamination of blood. When infected bodily fluids, such as blood, semen or vaginal fluid, is spread from one individual to another, contamination can occur.

In order to decrease the risk of transmitting HIV, patients should avoid sexual activity and/or the spread of sexual fluids. If patients do engage in sexual activity, they should always wear a condom and should use condoms made from polyurethane or latex. Patients should also avoid sharing medical equipment, such as needles, with anyone as this can lead to the transmission of HIV.

In relation to pregnancy, Lamivudine is classed as a category C medication. If Lamivudine is taken by pregnant patients, there is a risk that it will cause harm to the unborn fetus. Due to this, patients should use effective birth control when taking this medication.

If patients become pregnant when taking Lamivudine, they should inform their physician immediately. If patients plan to become pregnant, they should discuss this with their physician before trying to conceive. In some cases, the patient's treatment may be modified prior to pregnancy in order to reduce the risk to their future child.

It is not known whether Lamivudine can be excreted in breast milk and, if so, whether it poses a risk of infants. Due to this, patients are normally advised not to breastfeed whilst taking this medicine and should seek medical advice before doing so. However, patients with HIV are generally advised not to breastfeed as the HIV virus can be transmitted via breastfeeding.

If patients have any existing allergies or have ever exhibited an allergic reaction to any substances before, they should notify their doctor before they begin taking Lamivudine. This includes allergies to medicines, foods, animals, preservatives and/or dyes. In rare cases, patients may exhibit an allergic reaction when taking Lamivudine. If so, their symptoms may include:

  • Trouble breathing
  • Wheezing
  • Trouble swallowing
  • Hives
  • Shortness of breath
  • Itching
  • Hoarseness
  • Swelling of the face, lips, tongue, throat, mouth or hands
  • Rash on the skin

A serious allergic reaction is a life-threatening medical emergency. If patients exhibit the above symptoms when taking Lamivudine, they will need urgent medical attention.


When patients are prescribed Lamivudine, they are usually advised to take the medication at least once per day. In order to facilitate this, patients will need to keep a supply of medication at home. However, it's important that patients take precautions when storing Lamivudine and other medicines in the home.

For example, patients may want to use a lockable cabinet or a locked medicine box when storing Lamivudine. In addition to this, patients should ensure that children and/or pets cannot gain access to the medication as it could cause them significant harm.

In order to store Lamivudine properly, patients should follow the manufacturer's instructions and/or the medication guidelines. In most cases, Lamivudine can be stored at room temperature but should be kept in a closed container. Lamivudine will also need to be protected from moisture, heat and direct light.

If patients are advised to stop taking Lamivudine or if the medicine reaches its expiration date, patients will need to dispose of it carefully. Patients should not throw Lamivudine or any other medicine out with regular household waste as it may pose a risk to other people. Instead, patients should contact their physician's office or pharmacist and make use of a specialist medicine disposal service.


Although Lamivudine does not provide a cure for HIV or AIDS, it can be used to treat the virus. When taking Lamivudine, the human immunodeficiency virus remains in the patient's body but the patient's viral load of HIV in the patient's system may be reduced to a negligible amount.

Without treatment, the human immunodeficiency virus will destroy the patient's immune system and leave them susceptible to a range of life-threatening illnesses and infections. By using Lamivudine, however, the damage to the immune system can be stopped or lessened. As a result, the patient's overall health should improve and they should be less susceptible to other infections.

An early diagnosis and swift treatment can be crucial to the successful treatment of HIV. If Lamivudine and other medications are administered before the virus has been able to cause significant damage to the patient's immune system, then the patient is less likely to suffer from additional complications.

Although Lamivudine is not used to treat HIV as a monotherapy, it can be extremely effective when it is used in conjunction with other medications. When taken as part of a treatment plan, Lamivudine can, therefore, limit the effects of the human immunodeficiency virus, reduce the patient's symptoms and considerably improve their quality of life.