Dizziness, trouble sleeping, drowsiness, unusual dreams, and trouble concentrating may often occur. These side effects may begin 1-2 days after starting this medication and usually go away in 2-4 weeks. They are also reduced by taking this medication on an empty stomach at bedtime.
Tiredness, headache, diarrhea, and skin discoloration (such as small spots/freckles, darkening of the palms of the hands/soles of the feet) may also occur.
If any of these effects last or get worse, tell your doctor or pharmacist promptly.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
As your immune system gets stronger, it can begin to fight off infections you already had, possibly causing disease symptoms to come back. You could also have symptoms if your immune system becomes overactive. This reaction may happen at any time (soon after starting HIV treatment or many months later). Get medical help right away if you have any serious symptoms, including: unexplained weight loss, severe tiredness, muscle aches/weakness that doesn't go away, headaches that are severe or don't go away, joint pain, numbness/tingling of the hands/feet/arms/legs, vision changes, signs of infection (such as fever, chills, swollen lymph nodes, trouble breathing, cough, non-healing skin sores), signs of an overactive thyroid (such as irritability, nervousness, heat intolerance, fast/pounding/irregular heartbeat, bulging eyes, unusual growth in the neck/thyroid known as a goiter), signs of a certain nerve problem known as Guillain-Barre syndrome (such as unsteadiness, loss of coordination, trouble swallowing/speaking/chewing, trouble moving your eyes).
Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as depression, rare thoughts of suicide, strange thoughts, anxiety, angry behavior, hallucinations, confusion), loss of coordination, signs of kidney problems (such as a change in the amount of urine), unusual thirst, signs of pancreatitis (such as nausea, vomiting, stomach/abdominal/back pain, fever).
Rarely, this medication can cause severe (sometimes fatal) liver and blood problems (lactic acidosis). Tell your doctor right away if you develop symptoms of liver problems (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine) or lactic acidosis (such as deep/rapid breathing, drowsiness, nausea/vomiting, unusual weakness).
Changes in body fat may occur while you are taking this medication (such as increased fat in the upper back and stomach areas, decreased fat in the arms and legs). The cause and long-term effects of these changes are unknown. Discuss the risks and benefits of treatment with your doctor, as well as the possible use of exercise to reduce this side effect.
Tenofovir may increase the risk of bone loss. Discuss the risks and benefits of treatment with your doctor, as well as the possible use of calcium and vitamin D to reduce this side effect. If you are at risk for bone loss, your doctor may monitor your bone mineral density. Tell your doctor right away if any of the following serious side effects occur: bone pain, easily broken bones.
Get medical help right away if you have any very serious side effects, including: fast/irregular heartbeat, severe dizziness, fainting.
Efavirenz/emtricitabine/tenofovir can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Get medical help right away if you develop any rash.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, blisters, peeling skin, fever, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.