Efavirenz may cause serious psychiatric symptoms including confusion, severe depression, suicidal thoughts, aggression, extreme fear, hallucinations, or unusual behavior. Contact your doctor at once if you have any of these side effects, even if you have had them before.
Do not use this medication without telling your doctor if you are pregnant. It could harm the unborn baby. Use two forms of birth control, including a barrier form (such as a condom or diaphragm with spermicide gel) while you are taking efavirenz, and for at least 12 weeks after your treatment ends. Tell your doctor if you become pregnant during treatment.
Do not take efavirenz with astemizole (Hismanal), bepridil (Vascor), cisapride (Propulsid), pimozide (Orap), midazolam (Versed), triazolam (Halcion), voriconazole (Vfend), or ergot medicines such as dihydroergotamine (D.H.E. 45), ergonovine (Ergotrate), ergotamine (Ergomar, Cafergot, Wigraine), or methylergonovine (Methergine).
These drugs can cause life-threatening side effects if you use them while you are taking efavirenz.
There are many other medicines that can interact with efavirenz, or make it less effective. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
Taking this medication will not prevent you from passing HIV to other people. Talk with your doctor about safe methods of preventing HIV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.