VITEKTA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VITEKTA (VITEKTA).
VITEKTA (telaprevir) is a direct-acting antiviral agent that inhibits the NS3/4A serine protease of hepatitis C virus (HCV). This protease is essential for the cleavage of the HCV polyprotein into functional proteins required for viral replication. By blocking this enzyme, telaprevir disrupts viral replication and reduces viral load.
| Metabolism | Telaprevir is primarily metabolized by cytochrome P450 (CYP) 3A4 and to a lesser extent by CYP3A5. It is also a substrate of P-glycoprotein (P-gp). |
| Excretion | Primarily hepatic metabolism via CYP3A4, with 93% eliminated in feces as metabolites and 1% in urine as unchanged drug. |
| Half-life | Terminal elimination half-life is approximately 12 hours (range 10-14 hours) in healthy subjects, supporting once-daily dosing. |
| Protein binding | Approximately 99% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Apparent volume of distribution is 1.7 L/kg, indicating extensive tissue penetration and distribution beyond plasma volume. |
| Bioavailability | Oral bioavailability is approximately 70% in healthy subjects under fed conditions; food increases absorption (high-fat meal increases AUC by up to 50%). |
| Onset of Action | Oral: Onset of antiretroviral activity occurs within 2-4 hours after a single dose, with maximal viral suppression achieved by 2-4 weeks. |
| Duration of Action | Antiviral effect persists for 24 hours with once-daily dosing; duration is extended by co-administration with ritonavir or cobicistat due to pharmacokinetic boosting. |
800 mg orally once daily with food.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (CrCl ≥30 mL/min). Not recommended in patients with severe renal impairment (CrCl <30 mL/min) or end-stage renal disease (ESRD). |
| Liver impairment | Mild (Child-Pugh A): no adjustment. Moderate (Child-Pugh B): not recommended. Severe (Child-Pugh C): contraindicated. |
| Pediatric use | For children aged ≥6 years and weighing ≥25 kg: 800 mg once daily with food. For children weighing 15 to <25 kg: 600 mg once daily with food. Safety and efficacy not established in children <6 years or <15 kg. |
| Geriatric use | No specific dose adjustment required; however, caution due to increased frequency of renal and hepatic impairment, and potential for decreased renal function. Monitor renal function closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VITEKTA (VITEKTA).
| Breastfeeding | No data on human milk transfer; telaprevir is excreted in rat milk. M/P ratio unknown; because of potential for adverse effects in nursing infants, breastfeeding is not recommended during therapy and for 7 days after last dose. |
| Teratogenic Risk | VITEKTA (telaprevir) is contraindicated in pregnancy due to teratogenicity observed in animal studies; first-trimester exposure associated with major birth defects including neural tube defects and cardiovascular malformations. Second and third trimester: risk continues with potential fetal harm; use only if benefit justifies risk after thorough counseling. |
■ FDA Black Box Warning
None
| Serious Effects |
["Concomitant use with drugs highly dependent on CYP3A4 for clearance and for which elevated concentrations are associated with serious toxicity (e.g., alfuzosin, amiodarone, certain antiarrhythmics, ergot derivatives, lovastatin, simvastatin, midazolam [oral], pimozide, sildenafil [for pulmonary hypertension], triazolam).","Hypersensitivity to telaprevir or any component of the formulation.","Pregnancy (due to combination with ribavirin, which has a boxed warning for teratogenicity).","In combination with other direct-acting antivirals that are not recommended (historically, monotherapy is contraindicated due to rapid resistance development)."]
| Precautions | ["Rash, including severe cases (Stevens-Johnson syndrome, DRESS syndrome) – may require discontinuation; monitor for progression.","Anemia, including severe anemia requiring dose reduction or discontinuation of ribavirin.","Neutropenia and thrombocytopenia associated with peginterferon alfa; laboratory monitoring required.","Pancreatitis (rare but potentially fatal); discontinue if confirmed.","Cardiovascular events (e.g., worsening of pre-existing cardiac disease) related to anemia or interferon therapy.","Hepatic decompensation in patients with cirrhosis; monitor liver function closely.","Drug interactions due to CYP3A4 inhibition; telaprevir is a strong inhibitor of CYP3A4, increasing exposure of many drugs."] |
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| Fetal Monitoring | Pregnancy test required before initiation; monthly pregnancy testing during treatment; immediate ribavirin discontinuation if pregnancy occurs; fetal ultrasound and monitoring for anemia, hepatic function, and viral load. |
| Fertility Effects | Animal studies show testicular degeneration and reduced fertility in males; reversible upon discontinuation. Females: no impairment in fertility observed in rats; human data limited, but possible impact on spermatogenesis. |