Efavirenz/Lamivudine/Tenofovir Disoproxil Fumarate (Symfi, Symfi Lo) - Uses, Side Effects, and More

What are the most common side effects of efavirenz/lamivudine/tenofovir disoproxil fumarate?

The most common side effects of efavirenz/lamivudine/tenofovir disoproxil fumarate are listed below. Tell your health care provider if you have any of these side effects that bother you.

• Trouble concentrating
• Unusual dreams
• Headache
• Nausea
• General feeling of being unwell, tired, or not having your usual energy
• Nasal symptoms
• Diarrhea
• Rash (see below)
• Dizziness
• Trouble sleeping
• Pain
• Depressed mood
• Feeling unusually weak or tired
• Cough

There may be other side effects of efavirenz/lamivudine/tenofovir disoproxil fumarate that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of efavirenz/lamivudine/tenofovir disoproxil fumarate?

While less common, the most serious side effects of efavirenz/lamivudine/tenofovir disoproxil fumarate are described below, along with what to do if they happen.

Lactic Acidosis. Efavirenz/lamivudine/tenofovir disoproxil fumarate may cause lactic acidosis (a buildup of lactic acid in your blood), which can be serious. Stop taking efavirenz/lamivudine/tenofovir disoproxil fumarate and get help right away if you have any of the following symptoms of lactic acidosis.

• General ill feeling
• Muscle pain
• Trouble breathing
• Feeling drowsy, dizzy, or lightheaded
• Stomach pain, nausea, or vomiting
• Feeling cold
• Fast or irregular heartbeat

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking efavirenz/lamivudine/tenofovir disoproxil fumarate. Keep all appointments for blood work to check the health of your liver. Call your health care provider right away if you have any of the following symptoms of liver damage.

• Nausea or vomiting
• Stomach or belly pain
• Fever
• Weakness or unusual tiredness
• Itching
• Loss of appetite
• Light-colored poop
• Dark-colored urine (pee)
• Your skin or the whites of your eyes turning yellowish in color (called jaundice)

Kidney Damage. Kidney damage can happen when taking efavirenz/lamivudine/tenofovir disoproxil fumarate. Keep all appointments for blood tests to check the health of your kidneys. Call your health care provider right away if you have any of the following symptoms of kidney damage.

• Reduced need to pee
• Swelling in your feet, ankles, or legs
• Weakness or unusual tiredness
• Difficulty catching your breath or chest pain/pressure
• Confusion
• Nausea
• Seizures

Mental Health Symptoms. Efavirenz/lamivudine/tenofovir disoproxil fumarate may cause serious mental health symptoms, including depression, suicidal thoughts, or aggression. If you are about to harm yourself, call 911 or call or text 988, the Suicide & Crisis Lifeline. Tell your health care provider right away if you have any of the following symptoms or if you have been told by others you have these symptoms.

• Hearing, seeing, smelling, tasting, or otherwise perceiving things that others do not (hallucinations)
• Delusional thoughts, such as false beliefs that you are being controlled
• Disorganized thoughts, such as jumping between topics or having a hard time focusing
• Sudden decline in self-care, such as personal hygiene or academic/work performance
• Feeling unusually suspicious (paranoia), restless, agitated, aggressive, confused, or nervous
• Thoughts of hurting yourself or other people
• New or increased feelings of anxiety, depression, or other unusual changes in your mood or behavior

Central Nervous System (CNS) Effects. Efavirenz/lamivudine/tenofovir disoproxil fumarate can commonly cause central nervous system (CNS) effects, and they can sometimes be severe. Symptoms usually start the first or second day of treatment and get better after a couple of weeks, but some symptoms can happen months or years after starting this medicine. Call your health care provider right away if you have the following symptoms.

• Dizziness
• Trouble sleeping
• Confusion or trouble concentrating
• Sleepiness or unusual dreams
• Trouble with balance or coordination
• Slowed reaction time
• Memory problems

Rash or Skin Reactions. Efavirenz/lamivudine/tenofovir disoproxil fumarate can commonly cause a rash. Sometimes it can cause a severe rash or skin reaction, such as Stevens-Johnson syndrome (SJS), that can lead to death if not treated. If you get a rash, call your health care provider right away. Get emergency help if you have any of the following symptoms of SJS.

• Painful red or purple skin that looks burned and peels off
• Flat red rash or blisters on your skin, mouth, nose, and genitals
• Red, painful, watery eyes
• Flu-like symptoms including fever, chills, and muscle aches

Inflammation of the Pancreas (Pancreatitis). Efavirenz/lamivudine/tenofovir disoproxil fumarate may cause inflammation of the pancreas, which is called pancreatitis. Certain children may be at higher risk. Stop taking efavirenz/lamivudine/tenofovir disoproxil fumarate and call your health care provider right away if you have symptoms of pancreatitis, including vomiting or severe pain in the upper part of your belly that travels to your back.

Seizures. Some people who have taken efavirenz/lamivudine/tenofovir disoproxil fumarate have reported having seizures. There are many different types of seizures and some of them are not easy to recognize. Stop taking efavirenz/lamivudine/tenofovir disoproxil fumarate and call your health care provider if you have any of the following signs that a seizure is happening or could happen.

• Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
• Stiffening of your arms and legs
• Feeling anxious, nervous, confused, or a sense of dread
• Feeling dizzy or lightheaded
• Falling or losing consciousness

Weak Bones. Using efavirenz/lamivudine/tenofovir disoproxil fumarate for a long time may cause your bones to become weaker, leading to reduced bone density (osteopenia). It may also cause a more serious condition called osteoporosis, which can cause your bones to break (fracture) more easily. Tell your health care provider if you have any bone pain, muscle pain or weakness, pain in your hands or feet, or if you break a bone. Get a bone mineral density test if one is ordered for you.

Immune System Changes. When you start efavirenz/lamivudine/tenofovir disoproxil fumarate, your immune system might get stronger and start fighting infections that have been hiding inside your body for a long time. The type of symptoms you may have will depend on the infection. Tell your health care provider right away if you notice any of the following new symptoms of infection.

• Fever, sweats, chills, or muscle aches
• Swollen lymph nodes
• Vision problems
• Confusion, problems talking, or headache
• Skin problems, such as a painful rash or warts
• Cough or coughing up blood
• Weakness or coordination problems

Fat Redistribution. Some people taking efavirenz/lamivudine/tenofovir disoproxil fumarate have changes in how their body stores fat. You may get more fat around the belly, breasts, or upper back (buffalo hump). You may lose fat in your arms, legs, face, or butt. Tell your health care provider right away if you have any of these symptoms.

Heart Rhythm Changes. Efavirenz/lamivudine/tenofovir disoproxil fumarate may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take medicines that can prolong the QT interval. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

High Cholesterol Levels. Efavirenz/lamivudine/tenofovir disoproxil fumarate may increase the levels of cholesterol or triglycerides in your blood. Keep all appointments with your health care provider to check your blood work before starting and while you are taking this medicine.

Severe Allergic Reactions. Efavirenz/lamivudine/tenofovir disoproxil fumarate may cause allergic reactions, which can be serious. Stop taking efavirenz/lamivudine/tenofovir disoproxil fumarate and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain