Warning
LACTIC ACIDOSIS AND SEVERE HEPATOMEGALY WITH STEATOSIS, INCLUDING FATAL CASES, HAVE BEEN REPORTED WITH THE USE OF NUCLEOSIDE ANALOGS ALONE OR IN COMBINATION WITH OTHER ANTIRETROVIRALS (SEE WARNINGS).
VIRADAY IS NOT INDICATED FOR THE TREATMENT OF CHRONIC HEPATITIS B VIRUS (HBV) INFECTION AND THE SAFETY AND EFFICACY OF VIRADAY HAVE NOT BEEN ESTABLISHED IN PATIENTS COINFECTED WITH HBV AND HIV.
SEVERE ACUTE EXACERBATIONS OF HEPATITIS B HAVE BEEN REPORTED IN PATIENTS WHO HAVE DISCONTINUED EMTRICITABINE OR TENOFOVIR DISOPROXIL FUMARATE, BOTH OF WHICH ARE COMPONENTS OF VIRADAY. HEPATIC FUNCTION SHOULD BE MONITORED CLOSELY WITH BOTH CLINICAL AND LABORATORY FOLLOW-UP FOR AT LEAST SEVERAL MONTHS IN PATIENTS WHO DISCONTINUE VIRADAY AND ARE CO-INFECTED WITH HIV AND HBV. IF APPROPRIATE, INITIATION OF ANTI-HEPATITIS B THERAPY MAY BE WARRANTED (SEE WARNINGS).
Pharmacology
Efavirenz
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) of human immunodeficiency virus type 1 (HIV-1). Efavirenz activity is mediated predominantly by noncompetitive inhibition of HIV-1 reverse transcriptase (RT). HIV-2 RT and human cellular DNA polymerases alpha, beta, gamma, and delta are not inhibited by EFV.
Emtricitabine
Emtricitabine, a synthetic nucleoside analog of cytidine, is phosphorylated by cellular enzymes to form emtricitabine 5'-triphosphate. Emtricitabine 5'-triphosphate inhibits the activity of the HIV-1 reverse transcriptase (RT) by competing with the natural substrate deoxycytidine 5'-triphosphate and by being incorporated into nascent viral DNA which results in chain termination. Emtricitabine 5'- triphosphate is a weak inhibitor of mammalian DNA polymerase alpha, beta, epsilon and mitochondrial DNA polymerase gamma.
Tenofovir disoproxil fumarate
Tenofovir disoproxil fumarate (tenofovir DF) is an acyclic nucleoside phosphonate diester analog of adenosine monophosphate. Tenofovir DF requires initial diester hydrolysis for conversion to tenofovir and subsequent phosphorylations by cellular enzymes to form tenofovir diphosphate. Tenofovir diphosphate inhibits the activity of HIV-1 reverse transcriptase (RT) by competing with the natural substrate deoxyadenosine 5'-triphosphate and, after incorporation into DNA, by DNA chain termination. Tenofovir diphosphate is a weak inhibitor of mammalian DNA polymerases alpha, beta, and mitochondrial DNA polymerase gamma.
Indications
Viraday is indicated for the treatment of HIV-1 infection in adults.
Dosage and Administration
The dose of Viraday is one tablet once daily. It is recommended that Viraday be taken on an empty stomach, preferably at bedtime. Bedtime dosing may improve the tolerability of nervous system symptoms associated with efavirenz. The increased efavirenz concentrations observed following administration of efavirenz with food may lead to an increase in frequency of adverse events.
Renal Impairment
Because Viraday is a fixed-dose combination, it should not be prescribed for patients requiring dosage adjustment such as those with moderate or severe renal impairment (creatinine clearance <50 mL/min).
Pediatrics
Viraday is not indicated for use in pediatric patients.
Contraindications
Viraday is contraindicated in patients with previously demonstrated hypersensitivity to any of the components of the product.
Warnings and Precautions
Viraday comes with an extensive patient information leaflet that contains information about many warnings and precautions pertaining to this medicine. You are strongly advised to read the patient information leaflet before taking Viraday. If any of the conditions apply to you or you do not understand any of the conditons described in the leaflet, see your doctor or health professional.
Drug Interactions
Viraday comes with an extensive patient information leaflet that contains information about a wide range possible interactions to be aware while taking this medicine. You are strongly advised to read the patient information leaflet before taking Viraday. If any of the conditions described in the leaflet apply to you or you do not understand any of the conditions, see your doctor or health professional.
Overdosage
Efavirenz
Some patients accidentally taking 600 mg twice daily have reported increased nervous system symptoms. One patient experienced involuntary muscle contractions.
Treatment of overdose with efavirenz should consist of general supportive measures, including monitoring of vital signs and observation of the patient's clinical status. Administration of activated charcoal may be used to aid removal of unabsorbed efavirenz. There is no specific antidote for overdose with efavirenz. Since efavirenz is highly protein bound, dialysis is unlikely to remove significant quantities from blood.
Emtricitabine
Limited clinical experience is available at doses higher than the therapeutic dose of emtricitabine. In one clinical pharmacology study single doses of emtricitabine 1200 mg were administered to 11 patients. No severe adverse reactions were reported.
Haemodialysis treatment removes approximately 30% of the emtrictabine dose over a 3-hour dialysis period starting within 1.5 hours of emtricitabine dosing (blood flow rate of 400 mL/min and a dialysate flow rate of 600 mL/min). It is not known whether emtricitabine can be removed by peritoneal dialysis.
Tenofovir DF
Limited clinical experience at doses higher than the therapeutic dose of tenofovir DF 300 mg is available. In one study, 600 mg tenofovir DF was administered to 8 patients orally for 28 days, and no severe adverse reactions were reported. The effects of higher doses are not known.
Tenofovir is efficiently removed by haemodialysis with an extraction coefficient of approximately 54%. Following a single 300 mg dose of tenofovir DF, a 4-hour hemodialysis session removed approximately 10% of the administered tenofovir dose.
Storage
Store in a cool dry place away from moisture. Keep the container tightly closed and keep out of reach from children.
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