Generic name: lamivudine (oral route) [ la-MIV-ue-deen ]
Drug class: Nucleoside reverse transcriptase inhibitors (NRTIs)

Medically reviewed by Drugs.com. Last updated on Dec 27, 2022.

Commonly used brand name(s)

In the U.S.

• Epivir
• Epivir A/F
• Epivir HBV

In Canada

• 3tc
• Heptovir

Available Dosage Forms:

• Tablet
• Solution

Therapeutic Class: Antiretroviral Agent

Pharmacologic Class: Nucleoside Reverse Transcriptase Inhibitor

Uses for 3tc

Lamivudine is used in combination with other medicines for the treatment of the infection caused by the human immunodeficiency virus (HIV). HIV is the virus that causes acquired immune deficiency syndrome (AIDS).

Lamivudine will not cure or prevent HIV infection or AIDS. It helps keep HIV from reproducing and appears to slow down the destruction of the immune system. This may help delay the development of serious health problems usually related to AIDS or HIV disease from occurring. Lamivudine will not keep you from spreading HIV to other people. People who receive this medicine may continue to have other problems usually related to AIDS or HIV disease.

Lamivudine is also used to treat chronic (long-term) hepatitis B virus (HBV) infection.

This medicine is available only with your doctor''s prescription.

Before using 3tc

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of lamivudine for the treatment of HIV infection in children 3 months of age and older. However, safety and efficacy have not been established in children younger than 3 months of age.

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of lamivudine for the treatment of chronic hepatitis B infection in children 2 to 17 years of age. However, safety and efficacy have not been established in children younger than 2 years of age.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of lamivudine in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving lamivudine.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Cabotegravir
• Horsetail
• Orlistat
• Sorbitol
• Tacrolimus

Interactions with food/tobacco/alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Diabetes—The oral solution contains sucrose, which can make this condition worse.

• Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

• Liver disease—Use with caution. May make this condition worse.

• Pancreatitis (inflammation or swelling of the pancreas), history of—Epivir® should be used with caution. May make this condition worse.

Proper use of 3tc

This section provides information on the proper use of a number of products that contain lamivudine. It may not be specific to 3tc. Please read with care.

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine comes with a patient information leaflet. Read and follow the instructions carefully. Ask your doctor if you have any questions.

Epivir® and Epivir-HBV® both contain the same medicine, but Epivir® has more medicine in each tablet or dose of liquid. Use only the brand of this medicine that your doctor prescribed. If you have HIV or AIDS, you need to use Epivir®. If you have hepatitis B but you do not have HIV or AIDS, you can use Epivir-HBV®.

Your doctor may want to test you for HIV before you start using Epivir-HBV® and during your treatment. Your medicine may need to be changed based on these test results.

It is important to take Epivir® as part of a combination regimen. Take all of the medicines your doctor prescribed at the right time of day. This will make your medicines work better.

Keep using lamivudine for the full time of treatment, even if you or your child begin to feel better. Do not stop using it without checking first with your doctor. When your supply of the medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of the medicine.

If you are using the oral liquid, use a specially marked measuring spoon, dosing syringe, or medicine cup to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor''s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage forms (solution or tablets):
  • For treatment of hepatitis B infection:
    • Adults—100 milligrams (mg) once a day.
    • Children 2 to 17 years of age—Dose is based on body weight and must be determined by your doctor. The dose is usually 3 milligrams (mg) per kilogram (kg) of body weight per day. The doctor may increase your dose as needed. However, the dose is usually not more than 100 mg per day. If your child cannot swallow the tablets, he or she may take the oral liquid.
    • Children younger than 2 years of age—Use and dose must be determined by your doctor.
  • For treatment of HIV infection or AIDS:
    • Adults—300 milligrams (mg) once a day or 150 mg 2 times a day.
    • Children 3 months of age and older—
      • Solution: Dose is based on body weight and must be determined by your doctor. The dose is usually 5 milligrams (mg) per kilogram (kg) of body weight taken 2 times a day, or 10 mg per kg once a day. The doctor may increase your dose as needed. However, the dose is usually not more than 300 mg per day, taken with other HIV medicines.
      • Tablets: Dose is based on body weight and must be determined by your doctor. The dose is usually 150 to 300 mg per day. If your child weighs 14 kg or more, it is preferred that he or she take the scored tablet.
    • Children younger than 3 months of age—Use and dose must be determined by your doctor.

Note: Patients that require treatment for both hepatitis B and either AIDS or HIV should follow the dosing schedule for HIV or AIDS.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using 3tc

It is very important that your doctor check your or your child''s progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Do not use this medicine if you or your child is also taking zalcitabine or medicines containing emtricitabine or lamivudine (eg, Atripla®, Combivir®, Complera®, Emtriva®, Epzicom®, Stribild®, Trizivir®, Truvada®). Tell your doctor right away if you are using any of these medicines.

Two rare but serious reactions to this medicine are lactic acidosis (build-up of acid in the blood) and liver toxicity, including an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child has stomach discomfort or cramping, nausea, vomiting, or diarrhea, a decreased appetite, a general feeling of discomfort, muscle cramping or pain, unusual tiredness or weakness, trouble breathing, or yellow skin or eyes.

This medicine may cause worsening of hepatitis B infection when treatment is stopped. Talk to your doctor if you have any concerns about this.

Pancreatitis may occur while you are using Epivir®. Tell your doctor right away if you or your child has sudden and severe stomach pain, chills, constipation, nausea, vomiting, fever, or lightheadedness.

Your immune system may get stronger when you start using Epivir®. This could cause a hidden infection in your body to become active. Tell your doctor right away if you or your child notice any changes in your health.

Lamivudine does not decrease the risk of transmitting HIV infection or hepatitis B infection to others through sexual contact or by contamination through blood. HIV or hepatitis B may be acquired from or spread to others through infected body fluids, including blood, vaginal fluid, or semen. If you are infected, it is best to avoid any sexual activity involving an exchange of body fluids with other people. If you do have sex, always wear (or have your partner wear) a condom (“rubber”). Only use condoms made of latex or polyurethane and use them every time you have contact with semen, vaginal secretions, or blood. Also, do not re-use or share needles or equipment with anyone. If you have any questions about this, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

3tc side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Incidence not known

• Black, tarry stools
• bleeding gums
• bloating
• blood in the urine or stools
• blurred vision
• chills
• constipation
• cough
• dark urine
• decreased appetite
• diarrhea
• difficulty with swallowing
• dizziness
• dry mouth
• fast heartbeat
• fast, shallow breathing
• fever
• flushed, dry skin
• fruit-like breath odor
• general feeling of discomfort
• general tiredness and weakness
• increased hunger
• increased thirst
• increased urination
• indigestion
• light-colored stools
• loss of appetite
• muscle cramps, pain, stiffness, or spasms
• nausea
• pains in the stomach, side, or abdomen, possibly radiating to the back
• pinpoint red spots on the skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• right upper abdominal or stomach pain and fullness
• skin rash, hives, or itching
• sleepiness
• stomach discomfort
• tightness in the chest
• troubled breathing with exertion
• unexplained weight loss
• unusual bleeding or bruising
• unusual tiredness or weakness
• upper right abdominal or stomach pain
• vomiting
• yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Belching
• burning, tingling, numbness or pain in the hands, arms, feet, or legs
• depression
• general feeling of discomfort or illness
• headache
• heartburn
• indigestion
• joint pain
• sensation of pins and needles
• sore throat
• stabbing pain
• stomach discomfort, upset, or pain
• stuffy or runny nose
• trouble sleeping
• weight loss

Incidence not known

• Hair loss or thinning of the hair
• pale skin
• sweating
• weight gain around your neck, upper back, breast, face, or waist

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Frequently asked questions

• What is the difference between HIV treatments Symfi and Symfi Lo?
• How much does HIV treatment Cimduo cost?
• What drugs are contained in the HIV treatment Delstrigo?
• What drugs are contained in the HIV treatment Cimduo?
• What drugs are contained in the HIV treatment Symfi Lo?

View more FAQ

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

4-Way

Generic name: phenylephrine nasal [ FEN-il-EFF-rin ]
Brand names: 4-Way, Afrin 4 Hour Extra Moisturizing, Little Noses Decongestant, Nasal Four, Neo-Synephrine Nasal, Sinex Nasal Spray
Drug class: Nasal antihistamines and decongestants

Medically reviewed by Drugs.com on Jan 30, 2023. Written by Cerner Multum.

What is 4-Way?

Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

4-Way is used to treat nasal congestion and sinus pressure caused by allergies, the common cold, or the flu. Phenylephrine may be used to treat congestion of the tubes that drain fluid from your inner ears, called the eustachian (yoo-STAY-shun) tubes.

4-Way may also be used for purposes not listed in this medication guide.

Warnings

Do not use 4-Way if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Before taking this medicine

You should not use 4-Way if you are allergic to it.

Do not use 4-Way if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

Ask a doctor or pharmacist if it is safe for you to use this medicine if you have other medical conditions, especially:

• heart disease, heart rhythm disorder;

• high blood pressure;

• diabetes;

• glaucoma;

• a thyroid disorder; or

• an enlarged prostate or urination problems.

It is not known whether 4-Way will harm an unborn baby. Do not use this medicine without a doctor''s advice if you are pregnant.

It is not known whether phenylephrine nasal passes into breast milk or if it could harm a nursing baby. Do not use this medicine without a doctor''s advice if you are breast-feeding a baby.

How should I use 4-Way?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold medicine should be used only for a short time until your symptoms clear up.

Do not give 4-Way to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

4-Way is usually used every 4 hours. Follow the directions on the medicine label. Never use more of this medicine than directed on the label or prescribed by your doctor. Using this medicine too long can damage the lining of your nasal passages and lead to chronic nasal congestion.

To use the nasal spray:

• Blow your nose gently. Keep your head upright and insert the tip of the bottle into one nostril. Press your other nostril closed with your finger. Breathe in quickly and gently spray the medicine into your nose. Then use the spray in your other nostril.

• Do not blow your nose for at least a few minutes after using the nasal spray.

• If the spray gets in your eyes or mouth or on your skin, rinse with water.

• If the nasal spray has not been used for longer than 24 hours, prime it by spraying 1 or 2 times into a tissue.

After each use, clean the tip of the spray bottle with a clean tissue or rinse it with hot water, making sure that no water gets into the medicine bottle. Keep the cap on the bottle when not in use.

To use the nasal drops, lie on your back with your head tilted back. Insert the correct number of drops and remain lying in this position for several minutes. Gently turn your head from side to side.

To prevent the spread of infection, do not share 4-Way with anyone else.

Call your doctor if your symptoms do not improve after 3 days of treatment, or if you have a fever with a headache, cough, or skin rash.

If you need surgery, tell the surgeon ahead of time that you are using 4-Way. You may need to stop using the medicine for a short time.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Since 4-Way is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe dizziness or drowsiness, slow heart rate, and fainting.

What should I avoid while using 4-Way?

Avoid getting 4-Way in your eyes.

Ask a doctor or pharmacist before using any other cold, cough, or allergy medicine. Many combination medicines contain pseudoephedrine. Taking certain products together can cause you to get too much of this medicine.

4-Way side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

4-Way may cause serious side effects. Stop using 4-Way and call your doctor at once if you have:

• severe sneezing, runny or stuffy nose, redness or swelling in your nose, or other worsening nasal symptoms (may be a sign of overuse of 4-Way);

• severe stinging, burning, or irritation inside your nose;

• severe dizziness, restless feeling, nervousness, or insomnia;

• mood changes, unusual thoughts or behavior;

• tremors or shaking; or

• little or no urination.

Side effects may be more likely in older adults.

Common side effects of 4-Way may include:

• temporary sneezing;

• mild burning, dryness, cold feeling, or irritation inside your nose;

• headache, dizziness, weakness;

• feeling excited or restless (especially in children); or

• mild sleep problems.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect 4-Way?

Ask a doctor or pharmacist before using 4-Way if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Ask a doctor or pharmacist if it is safe for you to use 4-Way if you are also using any of the following drugs:

• other decongestants;

• an antidepressant;

• blood pressure medication; or

• diabetes medication.

This list is not complete. Other drugs may interact with phenylephrine nasal, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

Copyright 1996-2023 Cerner Multum, Inc. Version: 6.02.