This drug is used with other HIV medications to help control HIV infection. It helps to decrease the amount of HIV in your body so your immune system can work better. This lowers your chance of getting HIV complications (such as new infections, cancer) and improves your quality of life. Efavir (Efavirenz) belongs to a class of drugs known as non-nucleoside reverse transcriptase inhibitors (NNRTIs).
Mechanism of action:
Efavir (Efavirenz) falls in the NNRTI class of antiretrovirals. Both nucleoside and non-nucleoside RTIs inhibit the same target, the reverse transcriptase enzyme, an essential viral enzyme which transcribes viral RNA into DNA. Unlike nucleoside RTIs, which bind at the enzyme’s active site, NNRTIs act allosterically by binding to a distinct site away from the active site known as the NNRTI pocket.
Efavir (Efavirenz) is not effective against HIV-2, as the pocket of the HIV-2 reverse transcriptase has a different structure, which confers intrinsic resistance to the NNRTI class.
Dosage and Administration:
Use Efavir (Efavirenz) as directed by your doctor. Check the label on the medicine for exact dosing instructions.
· Take Efavir (Efavirenz) by mouth on an empty stomach. Taking Efavir (Efavirenz) with food, especially with a high-fat meal, may lead to increased blood levels of Efavir (Efavirenz). This may increase your risk of side effects.
· Take Efavir (Efavirenz) with a full glass of water (8 oz [240 mL]).
· Swallow Efavir (Efavirenz) whole. Do not break, crush, or chew before swallowing. If you cannot swallow Efavir (Efavirenz) whole, tell your doctor.
· Do NOT take more than the recommended dose, change your dose, or stop taking Efavir (Efavirenz) without checking with your doctor.
· Take Efavir (Efavirenz) at the same time every day, preferably at bedtime unless otherwise directed by your doctor.
· Continue to use Efavir (Efavirenz) even if you feel well. Do not miss any doses.
Dizziness, trouble sleeping, drowsiness, unusual dreams, and trouble concentrating may frequently 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 Efavir (Efavirenz) on an empty stomach at bedtime. Avoid alcohol and street drugs while taking Efavir (Efavirenz). They may worsen these side effects. Tiredness, headache, nausea, vomiting, and diarrhea may also occur.
Before taking Efavir (Efavirenz), tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Store Efavir (Efavirenz) at room temperature, between 68 and 77 degrees F (20 and 25 degrees C). Store in a tightly closed container away from heat, moisture, and light.