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Pharmacologic class: Nonnucleoside reverse transcriptase inhibitor
Therapeutic class: Antiretroviral
Pregnancy risk category D
Inhibits human immunodeficiency virus (HIV) reverse transcriptase (required for transcription of HIV-1 RNA to DNA), leading to viral cell death
Capsules: 50 mg, 200 mg
Tablets: 600 mg
Indications and dosages
➣ HIV infection (given with one or more additional antiretrovirals)
Adults and children older than age 3 and weighing more than 40 kg (88 lb): 600 mg P.O. once daily
Children weighing 32.5 to 40 kg (71.5 to 88 lb): 400 mg P.O. once daily
Children weighing 25 to 32.5 kg (55 to 71.5 lb): 350 mg P.O. once daily
Children weighing 20 to 25 kg (44 to 55 lb): 300 mg P.O. once daily
Children weighing 15 to 20 kg (33 to 44 lb): 250 mg P.O. once daily
Children weighing 10 to 15 kg (22 to 33 lb): 200 mg P.O. once daily
• Concurrent use of rifampin or voriconazole
• Hypersensitivity to drug
• Concurrent use of astemizole, cisapride, midazolam, triazolam, ergot derivatives, voriconazole, or bepridil
Use cautiously in:
• hypercholesterolemia, hepatic impairment, concurrent use of hepatotoxic drugs, mental illness, or substance abuse
• concurrent use of St. John's wort (use not recommended)
• pregnant or breastfeeding patients
• Give on empty stomach.
• Know that drug is given with other antiretrovirals.
CNS: dizziness, drowsiness, fatigue, insomnia, abnormal dreams, hypoesthesia, depression, headache, poor concentration, nervousness, anxiety, CNS depression, suicidal ideation
GI: nausea, diarrhea, flatulence, abdominal pain, dyspepsia
GU: hematuria, renal calculi
Respiratory: respiratory depression
Skin: rash, diaphoresis, pruritus,erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome
Other: increased appetite
Drug-drug. Azole antifungals (ketoconazole, voriconazole): decreased antifungal plasma concentration, increased efavirenz plasma concentration
Calcium channel blockers: possible decreased calcium channel blocker concentration
Clarithromycin, indinavir: reduced blood levels of these drugs
CNS depressants (including antidepressants, antihistamines, opioids): increased CNS depression
CYP450 inducers (including phenobarbital, rifabutin, rifampin): increased clearance and decreased blood level of efavirenz
CYP450 inhibitors, ergot alkaloids, estrogen, midazolam, ritonavir, triazolam: increased blood levels of these drugs, greater risk of serious adverse reactions (including arrhythmias, CNS and respiratory depression, and hepatotoxicity)
HMG-CoA reductase inhibitors: decreased plasma concentration of atorvastatin, pravastatin, and simvastatin
Hormonal contraceptives: increased ethinyl estradiol blood level
Protease inhibitors: decreased plasma level and efficacy of these drugs
Saquinavir: decreased saquinavir blood level
Warfarin: increased or decreased warfarin effects
Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, total cholesterol, triglycerides: increased levels
Urine cannabinoid test: false-positive result
Drug-food. High-fat meal: increased drug absorption
Drug-herbs. St. John's wort: decreased efavirenz blood level and efficacy, drug resistance
Drug-behaviors. Alcohol use: increased CNS depression
• Monitor dietary intake and hepatic and lipid profile.
• Closely monitor patients with hepatic failure.
☞ Record mood changes and stay alert for suicidal ideation or behavior.
• Be aware that drug may cause hypercholesterolemia.
• Know that amount of HIV in blood may increase if patient stops drug therapy even briefly.
• Instruct patient to take with full glass of water, preferably at bedtime to improve tolerance of CNS effects. Also tell him to avoid taking drug with high-fat meals.
• Inform patient that drug must be taken in combination with other antiretrovirals.
• Tell patient that drug doesn't cure HIV or AIDS and that he can still transmit virus to others.
☞ Advise patient to report suicidal thoughts and other psychiatric symptoms.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
☞ Tell female patient to immediately inform prescriber if she becomes pregnant.
• Advise female patient to use adequate contraceptive measures for 12 weeks after discontinuing drug.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.
Pharmacologic: non nucleoside reverse transcriptase inhibitors
Time/action profile (blood levels)
|PO||rapid||3–5 hr||24 hr|
Adverse Reactions/Side Effects
Central nervous system
- abnormal dreams
- impaired concentration
- psychiatric symptomatology
- hepatotoxicity (life-threatening)
- nausea (most frequent)
- abdominal pain
- renal calculi
- rash (most frequent)
- fat redistribution
- immune reconstitution syndrome
Drug-Drug interaction↑ levels of pimozide, midazolam, triazolam, or ergot alkaloids when used concurrently; may result in potentially serious adverse reactions including arrhythmias, CNS, and respiratory depression (concurrent use contraindicated).Induces (stimulates) the hepatic cytochrome P450 3A4 enzyme system and would be expected to influence the effects of other drugs that are metabolized by this system; efavirenz itself is also metabolized by this system.↑ risk of CNS depression with other CNS depressants, including alcohol, antidepressants, antihistamines, and opioid analgesics.Concurrent use with ritonavir ↑ levels of both agents and the likelihood of adverse reactions, especially hepatotoxicity.May ↓ the effectiveness of progestin-containing hormonal contraceptives (e.g., etonogestrel, norelgestromin, levonorgestrel).Use with voriconazole significantly ↓ voriconazole levels and ↑ efavirenz levels; concurrent use with standard doses of voriconazole is contraindicated; if used together, ↑ dose of voriconazole to 400 mg q 12 hr and ↓ dose of efavirenz to 300 mg daily.May ↓ posaconazole levels (avoid concurrent use).↓ indinavir levels (indinavir dose ↑ recommended).↓ saquinavir levels (avoid using saquinavir as the only protease inhibitor with efavirenz).↓ maraviroc levels (maraviroc dose ↑ recommended).May alter the effects of warfarin.May ↓ levels of cyclosporine, tacrolimus, and sirolimus.May ↓ levels of bupropion and sertraline.Rifampin may ↓ levels (↑ dose of efavirenz)Concurrent use with other NNRTIs including etravirine, nevirapine, rilpivirine, and delavirdine may lead to ↓ effectiveness and should be avoided.May ↓ levels of raltegravir May ↓ levels of boceprevir ; avoid concurrent useConcurrent use with telaprevir may ↓ levels of telaprevir and efavirenzUse with St. John’s wort may cause ↓ levels and effectiveness, including development of drug resistance (concurrent use contraindicated).Ingestion following a high-fat meal ↑ absorption by 50%.
- Assess for change in severity of HIV symptoms and for symptoms of opportunistic infections during therapy.
- Assess for rash, especially during 1st mo of therapy. Onset is usually within 2 wk and resolves with continued therapy within 1 mo. May range from mild maculopapular with erythema and pruritus to exfoliative dermatitis and Stevens-Johnson syndrome. Occurs more often and may be more severe in children. If rash is severe or accompanied by blistering, desquamation, mucosal involvement, or fever, therapy must be discontinued immediately. Efavirenz may be reinstated concurrently with antihistamines or corticosteroids in patients discontinuing due to rash.
- Assess patient for CNS and psychiatric symptoms (dizziness, impaired concentration, somnolence, abnormal dreams, insomnia) during therapy. Symptoms usually begin during 1st or 2nd day of therapy and resolve after 2–4 wk. Administration at bedtime may minimize symptoms. Concurrent use with alcohol or psychoactive agents may cause additive CNS symptoms.
- Lab Test Considerations: Monitor viral load and CD4 cell count regularly during therapy.
- Monitor liver function tests in patients with a history of hepatitis B or C or underlying liver disease. May cause ↑ serum AST, ALT, and GGT concentrations. If moderate to severe liver function test abnormalities occur, efavirenz doses should be held until levels return to normal. Discontinue if liver function abnormalities recur when therapy is resumed.
- May cause ↑ in total cholesterol and serum triglyceride levels.
- Obtain a pregnancy test prior to starting therapy. May cause fetal harm if administered during first trimester of pregnancy.
- May cause false-positive urine cannabinoid results.
Potential Nursing DiagnosesRisk for infection (Indications)
Noncompliance (Patient/Family Teaching)
- Oral: Administer on an empty stomach, preferably at bedtime to minimize nervous system side effects. Avoid taking with a high-fat meal. Do not break tablets.
- Capsule may be opened and contents sprinkled on a small amount (1 to 2 tsp) of food for children at least 3 mo old and weighing at least 3.5 kg and adults who cannot swallow capsules or tablets. Open capsule carefully; avoid spillage or dispersion of contents into the air. For infants receiving capsule sprinkle-infant formula mixture, gently mix entire capsule contents into 2 tsp (10 mL) of reconstituted room temperature infant formula in a medicine cup, then draw up mixture into a 10 mL oral dosing syringe for administration. Use of infant formula for mixing should only be considered for those young infants who cannot consume solid foods. For patients able to tolerate solid foods, mix entire capsule contents gently with soft food (applesauce, grape jelly, yogurt). After administration of mixture, add a small amount (2 tsp) of food or formula to empty mixing container, stir to disperse any remaining efavirenz residue, and administer to patient. Administer mixture within 30 minutes of mixing. Avoid food for 2 hr after administration.
- Emphasize the importance of taking efavirenz as directed. It must always be used in combination with other antiretroviral drugs. Do not take more than prescribed amount, and do not stop taking without consulting health care professional. Take missed doses as soon as remembered; do not double doses.
- Instruct patient that efavirenz should not be shared with others.
- May cause dizziness, impaired concentration, or drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
- Instruct patient to notify health care professional immediately if rash occurs.
- Inform patient that efavirenz does not cure AIDS or prevent associated or opportunistic infections. Efavirenz does not reduce the risk of transmission of HIV to others through sexual contact or blood contamination. Caution patient to use a condom and to avoid sharing needles or donating blood to prevent spreading the AIDS virus to others. Advise patient that the long-term effects of efavirenz are unknown at this time.
- Inform patient that redistribution and accumulation of body fat may occur, causing central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, breast enlargement, and cushingoid appearance. The cause and long-term effects are not known.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
- Advise patients taking oral contraceptives to use a nonhormonal method of birth control during efavirenz therapy and for at least 12 wk following discontinuation and to notify health care professional if they become pregnant while taking efavirenz. Encourage patients who become pregnant during therapy to join the registry by calling 1-800-258-4263.
- Emphasize the importance of regular follow-up exams and blood counts to determine progress and monitor for side effects.
- Delayed progression of AIDS and decreased opportunistic infections in patients with HIV.
- Decrease in viral load and increase in CD4 cell counts.