efavirenz

efavirenz /ef·a·vi·renz/ (ef´ah-vi?renz) an antiretroviral, inhibiting reverse transcriptase; used in the treatment of HIV infection.

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e·fa·vir·enz (-fävîr-nz)

n.

A non-nucleoside drug used to treat HIV infection.

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efavirenz

Sustiva

Pharmacologic class: Nonnucleoside reverse transcriptase inhibitor

Therapeutic class: Antiretroviral

Pregnancy risk category C

Action

Inhibits human immunodeficiency virus (HIV) reverse transcriptase (required for transcription of HIV-1 RNA to DNA), leading to viral cell death

Availability

Capsules: 50 mg, 100 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

Contraindications

• Hypersensitivity to drug
• Concurrent use of astemizole, cisapride, midazolam, triazolam, or ergot derivatives

Precautions

Use cautiously in:
• hypercholesterolemia, hepatic impairment, concurrent use of hepatotoxic drugs, mental illness, or substance abuse
• pregnant or breastfeeding patients
• children.

Administration

• Give on empty stomach.
• Know that drug is given with other antiretrovirals.

Route	Onset	Peak	Duration
P.O.	Rapid	3-5 hr	24 hr

Adverse reactions

CNS: dizziness, drowsiness, fatigue, insomnia, abnormal dreams, hypoesthesia, depression, headache, poor concentration, nervousness, anxiety, CNS depression, suicidal ideation

CV: arrhythmias

GI: nausea, diarrhea, flatulence, abdominal pain, dyspepsia

GU: hematuria, renal calculi

Hepatic: hepatotoxicity

Respiratory: respiratory depression

Skin: rash, diaphoresis, pruritus, erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome

Other: increased appetite

Interactions

Drug-drug. 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

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)

Hormonal contraceptives: increased ethinyl estradiol blood level

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

Patient monitoring

• 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.

Patient teaching

• 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.
• 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.

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efavirenz Sustiva™ AIDS A reverse transcriptase inhibitor used with other antivirals–eg, zidovudine, lamivudine for HIV-1 infection Adverse effects N&V, maculopapular rash, fatigue, headache, dizziness. Cf Non-nucleoside reverse transcriptase inhibitor.