efavirenz
efavirenz
[ef´ah-vi″renz]efavirenz
Pharmacologic class: Nonnucleoside reverse transcriptase inhibitor
Therapeutic class: Antiretroviral
Pregnancy risk category D
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, 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
Dosage adjustment
• Concurrent use of rifampin or voriconazole
Contraindications
• Hypersensitivity to drug
• Concurrent use of astemizole, cisapride, midazolam, triazolam, ergot derivatives, voriconazole, or bepridil
Precautions
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
• children.
Administration
• Give on empty stomach.
• Know that drug is given with other antiretrovirals.
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. 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
Patient monitoring
• Monitor dietary intake and hepatic and lipid profile.
• Closely monitor patients with hepatic failure.
See 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.
See 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.
See 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.