bik-TEG-ra-vir/em-trye-SYE-ta-been/ten-OF-oh-veer al-a-FEN-a-mide

Therapeutic Classification: antiretrovirals

Pharmacologic Classification: nucleoside reverse transcriptase inhibitors, integrase strand transfer inhibitors (INSTI)

• HIV infection in patients who have no antiretroviral treatment history or in those on a stable antiretroviral regimen who are virologically suppressed (with HIV-1 RNA <50 copies/mL) and no history of treatment failure or no known substitutions associated with resistance to bictegravir or tenofovir (to replace their current antiretroviral regimen).

• Bictegravir: Inhibits HIV-1 integrase, which is required for viral replication; Emtricitabine: Phosphorylated intracellularly where it inhibits HIV reverse transcriptase, resulting in viral DNA chain termination; Tenofovir: Phosphorylated intracellularly where it inhibits HIV reverse transcriptase resulting in disruption of DNA synthesis.

• Slowed progression of HIV infection and decreased occurrence of sequelae.

Bictegravir

Absorption: Extent of absorption following oral administration unknown.

Distribution: Unknown.

Protein Binding: >99%.

Metabolism/Excretion: Primarily metabolized by the CYP3A4 isoenzyme and UGT1A1 in the liver; 60% excreted in feces, 35% excreted in urine.

Half-life: 17.3 hr;.

Emtricitabine

Absorption: Well absorbed (93%) following oral administration.

Distribution: Unknown.

Metabolism/Excretion: Undergoes some metabolism, 70% excreted in urine, 14% excreted in feces.

Half-life: 10.4 hr.

Tenofovir Alafenamide

Absorption: Tenofovir alafenamide is a prodrug, which is hydrolyzed into tenofovir, the active component; absorption enhanced by high-fat meals.

Distribution: Unknown.

Metabolism/Excretion: Tenofovir is phosphorylated to tenofovir diphosphate (active metabolite); 32% excreted in feces, <1% excreted in urine.

Half-life: Tenofovir alafenamide: 0.51 hr; Tenofovir diphosphate: 150–180 hr.

(plasma concentrations)

Contraindicated in:

• Concurrent use of dofetilide or rifampin
• Severe renal impairment (CCr 15–30 mL/min) or end-stage renal disease (CCr <15 mL/min) not receiving hemodialysis
• Patients with no antiretroviral treatment history and end-stage renal disease (CCr <15 mL/min) who are receiving chronic hemodialysis
• Severe hepatic impairment.

Use Cautiously in:

• Hepatitis B virus (HBV) coinfection
• History of suicidal ideation or depression (↑ risk of suicidal thoughts)
• Renal impairment or receiving nephrotoxic medications (↑ risk of renal impairment)
• OB: Recommended in pregnant individuals who are virologically suppressed on a stable antiretroviral regimen with no known substitutions associated with resistance to bictegravir, emtricitabine, or tenofovir alafenamide
• Lactation: Safety of bictegravir not established in breastfeeding; breastfeeding should be supported in people with HIV who are taking antiretroviral therapy, as prescribed, and are maintaining an undetectable amount of virus in the body
• Pedi: Children weighing <14 kg (safety and effectiveness not established).

GI: ↑amylase, ↑ liver enzymes, ACUTE EXACERBATION OF HBV, diarrhea, LACTIC ACIDOSIS/HEPATOMEGALY WITH STEATOSIS, nausea.

GU: ACUTE RENAL FAILURE/FANCONI SYNDROME.

Hemat: neutropenia.

Metab: hyperlipidemia.

MS: ↑creatine kinase.

Neuro: abnormal dreams, dizziness, fatigue, headache, insomnia.
Misc: immune reconstitution syndrome.

Drug-Drug:

• Bictegravir may ↑ dofetilide levels and the risk of torsades de pointes; concurrent use contraindicated.
• Rifampin may ↓ bictegravir levels and its effectiveness; concurrent use contraindicated.
• Medications that compete for active tubular secretion, including acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, or aminoglycosides, may ↑ emtricitabine and tenofovir levels and risk of toxicity.
• Nephrotoxic agents, including NSAIDs, ↑ risk of nephrotoxicity with tenofovir; avoid concurrent use.
• Carbamazepine, oxcarbazepine, phenobarbital, phenytoin, rifabutin, and rifapentine may ↓ bictegravir and tenofovir levels and their effectiveness; avoid concurrent use.
• Administration with antacids containing magnesium or aluminum↓ absorption of bictegravir; take 2 hr before or 6 hr after magnesium- or aluminum-containing antacids.
• Administration with supplements or antacids containing calcium or iron↓ absorption of bictegravir; take at the same time as calcium or iron supplements with food (and not on an empty stomach).
• May ↑ metformin levels and risk of toxicity.

Drug-Natural Products:

• St. John's wort may ↓ bictegravir and tenofovir levels and their effectiveness; avoid concurrent use.

• PO (Adults and Children 25 kg): 1 tablet (bictegravir 50 mg/emtricitabine 200 mg/tenofovir alafenamide 25 mg) once daily.
• PO (Children 14–24 kg): 1 tablet (bictegravir 30 mg/emtricitabine 120 mg/tenofovir alafenamide 15 mg) once daily.

• Tablets: bictegravir 30 mg/emtricitabine 120 mg/tenofovir alafenamide 15 mg; bictegravir 50 mg/emtricitabine 200 mg/tenofovir alafenamide 25 mg;

• Assess patient for change in severity of HIV symptoms and for symptoms of opportunistic infections during therapy.
• May cause lactic acidosis and severe hepatomegaly with steatosis. Monitor patient for signs (↑ serum lactate levels, ↑ liver enzymes, liver enlargement on palpation). Suspend therapy if clinical or laboratory signs occur.

• Monitor viral load and CD4 cell count regularly during therapy.
  • Test patients for chronic HBV before initiating therapy. Medication is not indicated for treatment of HBV. Exacerbations of HBV have occurred upon discontinuation of therapy.
  • Assess serum creatinine, estimated CCr, urine glucose, and urine protein prior to and periodically during therapy. Also monitor serum phosphorous in patients with chronic kidney disease. Discontinue therapy in patients who develop clinically significant ↓ renal function or evidence of Fanconi syndrome.
  • Monitor liver function tests in patients coinfected with HIV and HBV who discontinue Biktarvy. May cause an exacerbation of HBV. May cause ↑ AST, ALT, bilirubin, creatine kinase, serum amylase, serum lipase, and triglycerides.
  • May cause ↓ neutrophil count.
  • May cause ↑ LDL cholesterol.

• PO: Administer once daily without regard for food.
• Administer medication at least 2 hr before or 6 hr after antacids containing aluminum or magnesium. Medication may be taken with food at same time as supplements or antacids containing iron or calcium.

• Emphasize the importance of taking medication as directed. Do not take more than prescribed amount, and do not stop taking without consulting health care professional. Take missed doses as soon as remembered, but not if almost time for next dose; do not double doses. Advise patient to read Patient Information before starting therapy and with each Rx refill in case of changes.
• Instruct patient that medication should not be shared with others.
• Inform patient that medication does not cure HIV or prevent associated or opportunistic infections. Therapy may 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 HIV to others.
• Instruct patient to notify health care professional immediately if signs/symptoms of lactic acidosis (tiredness or weakness, unusual muscle pain, trouble breathing, stomach pain with nausea and vomiting, cold especially in arms or legs, dizziness, fast or irregular heartbeat) or if signs/symptoms of hepatotoxicity (yellow skin or whites of eyes, dark urine, light-colored stools, lack of appetite for several days or longer, nausea, abdominal pain) occur.
• Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications, especially St. John's wort.
• Advise patient to notify health care professional if signs and symptoms of immune reconstitution syndrome (signs and symptoms of an infection) occur.
• Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding is planned. Enroll pregnant patients in the Antiretroviral Pregnancy 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 HIV and decreased opportunistic infections in patients with HIV.
• Decrease in viral load and increase in CD4 cell counts.

Biktarvy