Efavirenz information from DrugsUpdate
P - Caution when used during pregnancy
L - Contraindicated in lactation
LI - Lab *
Efavirenz (brand names Sustiva and Stocrin) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and is used as part of highly active antiretroviral therapy (HAART) for the treatment of a human immunodeficiency virus (HIV) type 1. For HIV infection that has not previously been treated, the United States Department of Health and Human Services Panel on Antiretroviral Guidelines currently recommends the use of efavirenz in combination with lamivudine/zidovudine (Combivir) or tenofovir/emtricitabine (Truvada) as the preferred NNRTI-based regimens in adults and adolescents. Efavirenz is also used in combination with other antiretroviral agents as part of an expanded postexposure prophylaxis regimen to reduce the risk of HIV infection in people exposed to a significant risk (e.g. needlestick injuries, certain types of unprotected sex etc.). The usual adult dose is 600 mg once a day. It is usually taken on an empty stomach at bedtime to reduce neurological and psychiatric adverse effects. Efavirenz was combined with the popular HIV medication Truvada, which consists of tenofovir and emtricitabine, all of which are reverse transcriptase inhibitors. This combination of three medications approved by the U.S. Food and Drug Administration (FDA) in July 2006 under the brand name Atripla, provides HAART in a single tablet taken once a day. It results in a simplified drug regimen for many patients.
Pharmacodynamics
Pharmacokinetics
Efavirenz, a non-nucleoside reverse transcriptase inhibitor with activity against HIV, blocks the RNA-dependent and DNA-dependent polymerase activities including HIV replication.
Absorption Absorbed after oral doses; plasma concentrations peak after about 5 hr.
Distribution> 99% bound to plasma proteins.
Metabolism Metabolized mainly by CYP3A4 and CYP2B6.
Excretion About 14-34% of a dose is excreted in the urine as metabolites, and 16-61% in the faeces.
Efavirenz Indications / Efavirenz Uses
Information Not Available
Efavirenz Adverse Reactions / Efavirenz Side Effects
Rash including Stevens-Johnson syndrome and erythema multiforme; CNS effects e.g. dizziness, headache, insomnia, somnolence, abnormal dreams, fatigue, impaired concentration. Nausea, less frequently, vomiting, diarrhoea, hepatitis, depression, anxiety, psychosis, amnesia and ataxia, stupor, vertigo, abdominal pain, hepatic failure, pancreatitis, convulsions, gynaecomastia, pruritus, blurred vision.
Precautions
Monitor Consider monitoring cholesterol and triglycerides. Monitor LFTs in patients with history of hepatitis B and/or C. Hepatic Function Use with caution. Convulsions Use with caution in patients with history of seizures. Convulsions have been reported. CNS symptoms Reported in 53% of patients. Fat redistribution Redistribution/accumulation of body fat, including central obesity, dorsocervical fat enlargement, peripheral wasting, facial wasting, breast enlargement, and cushingoid appearance, may occur. Hepatitis Monitor liver enzymes in patients with known or suspected history of hepatitis B or C infection and in patients receiving medication associated with liver toxicity. Immune reconstitution syndrome May occur, necessitating further evaluation and treatment. Lipids Increases in total cholesterol and triglycerides have been reported. Monotherapy Resistant virus may emerge rapidly. Psychiatric symptoms Serious adverse psychiatric experiences have been reported. Patients with a history of psychiatric disorders may be at greater risk. There have been occasional reports of death by suicide, delusions, and psychosis-like behavior. Skin rash Reported in 26% of adults and 46% of children. Overdosage Symptoms Increased CNS symptoms, involuntary muscle contractions.
Special Precautions
Mild to moderate liver disease; renal impairment. Monitor liver enzymes and cholesterol. Discontinue if severe skin rash or fever develops; known or suspected hepatitis B or infection. History of mental illness or seizures; elderly. Pregnancy. Children.
Other Drug Interactions
Hormonal contraceptives; antibacterial e.g. rifampicin, rifabutin, clarithromycin; enzyme inducers. St. John's wort may decrease serum level. Ethanol (hepatic and CNS adverse effects). Potentially Fatal: Life-threatening adverse effects when used with terfenadine, astemizole, cisapride, midazolam, triazolam and ergot alkaloids.
Other Interactions
Food Interactions: High-fat meals increase absorption of efavirenz. Grapefruit juice inhibits its metabolism.
Dosage
Oral HIV infection Adult: Combined with other antiretrovirals: 600 mg once daily. Dosing at bedtime recommended during 1st 2-4 wk of therapy to improve tolerability. Child: Combined with other antiretrovirals: >3 yr, 10-14 kg: 200 mg; 15-19 kg: 250 mg; 20-24 kg: 300 mg; 25-32.4 kg: 350 mg; 32.5-39 kg: 400 mg; ≥40 kg: 600 mg. To be taken once daily.
Food(before/after)
Stocrin?: May be taken with or without food. Sustiva?: Should be taken on an empty stomach. (Take on an empty stomach, preferably at bedtime.)
List of Contraindications
Efavirenz and Pregnancy
Caution when used during pregnancy. Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).
Efavirenz and Lactation
Contraindicated in lactation
Efavirenz and Children
Information Not Available
Efavirenz and Geriatic
Use with caution because of the greater frequency of decreased hepatic, renal, or cardiac function, and concomitant diseases or other drug therapy.
Efavirenz and Other Contraindications
Severe hepatic impairment; hypersensitivity; lactation
Storage
Oral Store at 15-30 ℃
Lab interference
Oral Store at 15-30 ℃
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