Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Birth control: Methods of birth control that use hormones, such as a birth control pill, patch or injection, may not be fully reliable as efavirenz interacts with many medications and may change the way that your body uses the hormones. At least 2 forms of non-hormonal birth control (condom, diaphragm) should be used while you are taking this medication. It is recommended that a woman not attempt to become pregnant until at least 12 weeks after stopping this medication, to give the medication time to leave the body.
Depression: Anti-retroviral medications have been known to cause mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication contact your doctor as soon as possible.
Drowsiness/reduced alertness: Side effects of efavirenz may include dizziness, drowsiness, and trouble concentrating. You should not undertake activities requiring mental alertness or physical coordination until you determine that efavirenz does not affect you in this way.
Fat redistribution: Over time, this medication may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, breast, around the back, chest, and stomach area; or loss of fat from the legs, arms, and face. The long-term effects of this are not known.
Immune reconstitution syndrome: This medication may cause immune reconstitution syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medication and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms (such as pneumonia, herpes or tuberculosis). Report any new symptoms to your doctor immediately.
Liver function: If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.
If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.
Pancreatitis: Efavirenz can cause the pancreas to become inflamed. If you have a history of pancreatitis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Report signs of pancreatitis such as abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, or swollen abdomen to your doctor immediately.
If you have a history of pancreatitis, gallstones, alcoholism, or high triglycerides, you may be more at risk of experiencing this.
Seizures: There have been occasional reports of seizures occurring when taking efavirenz. If you have a history of epilepsy or medical conditions that increase the risk of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Stopping the medication: If you stop taking this medication, your HIV infection could get worse. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.
Pregnancy: Women should avoid becoming pregnant while taking efavirenz as this medication may cause harm to a developing baby if it is taken during the first trimester of pregnancy. Your doctor should test you for pregnancy before starting this medication. If you become pregnant while taking this medication, talk with your doctor before stopping the medication. After assessing the risks and benefits of efavirenz in your particular situation, your doctor may recommend that you continue the medication.
Breast-feeding: It is not known if efavirenz passes into breast milk. Women who have HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection.
Children: The safety and effectiveness of using this medication have not been established for children less than 3 years of age or weighing less than 13 kg.