Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
PREZCOBIX vs PREZCOBIX PED
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
PREZCOBIX is a fixed-dose combination of darunavir, a HIV-1 protease inhibitor, and cobicistat, a CYP3A inhibitor. Darunavir selectively inhibits the cleavage of HIV-encoded Gag-Pol polyproteins in infected cells, preventing the formation of mature infectious virions. Cobicistat increases systemic exposure of darunavir by inhibiting CYP3A-mediated metabolism.
Darumavir is an HIV-1 protease inhibitor that inhibits the cleavage of HIV-1 Gag-Pol polyproteins, resulting in non-infectious immature viral particles. Cobicistat is a CYP3A inhibitor that boosts darunavir exposure without contributing to antiviral activity.
Treatment of HIV-1 infection in combination with other antiretroviral agents in adults and pediatric patients weighing at least 40 kg
Treatment of HIV-1 infection in pediatric patients weighing at least 15 kg in combination with other antiretroviral agents,FDA-approved for pediatric patients with HIV-1
Darunavir 800 mg (as two 400 mg tablets) plus cobicistat 150 mg (as one 150 mg tablet) orally once daily with food.
PREZCOBIX PED is a pediatric formulation; adult dosing is not applicable. For adults, the equivalent product is PREZCOBIX (darunavir/cobicistat) fixed-dose combination: 800 mg/150 mg orally once daily with food.
Darunavir: terminal half-life of approximately 15 hours when coadministered with cobicistat, supporting once-daily dosing. Cobicistat: terminal half-life of approximately 3-4 hours, but its inhibitory effect on CYP3A4 persists for 24 hours.
Darunavir: ~15 hours (with cobicistat). Cobicistat: ~3-4 hours.
Darunavir is primarily metabolized by CYP3A. Cobicistat is a CYP3A inhibitor and is metabolized by CYP3A and to a minor extent by CYP2D6.
Darumavir is extensively metabolized by CYP3A; cobicistat is a mechanism-based inhibitor of CYP3A and is metabolized by CYP3A and to a minor extent by CYP2D6.
Darunavir: approximately 79.5% in feces (41% as unchanged drug) and 13.9% in urine (7.7% as unchanged drug). Cobicistat: 86% in feces and 8.2% in urine.
Darunavir: ~80% fecal (mostly as parent), ~14% renal (3% unchanged). Cobicistat: ~86% fecal, ~8% renal.
Darunavir: approximately 95% bound to plasma proteins (primarily alpha-1-acid glycoprotein). Cobicistat: 97-98% bound to plasma proteins.
Darunavir: ~95% bound to alpha-1-acid glycoprotein (AAG). Cobicistat: ~97-98% bound to plasma proteins.
Darunavir: apparent Vd of 0.54 L/kg (based on a 70 kg adult, approximately 38 L), indicating distribution into total body water. Cobicistat: apparent Vd of 0.42 L/kg (approximately 29 L).
Darunavir: Vd ~88 L (1.3 L/kg for 70 kg adult). Cobicistat: Vd ~144 L (2.1 L/kg for 70 kg adult).
Darunavir: absolute bioavailability is approximately 37% without a boosting agent; when coadministered with cobicistat, bioavailability is enhanced due to inhibition of CYP3A4-mediated first-pass metabolism, but the exact boosted bioavailability is not separately reported. Cobicistat: absolute bioavailability is not determined; it is used as a pharmacokinetic enhancer.
Darunavir: ~82% (with cobicistat, relative to ritonavir-boosted). Cobicistat: ~70%.
No dose adjustment required in renal impairment including end-stage renal disease on hemodialysis. Cobicistat may decrease estimated creatinine clearance due to tubular secretion inhibition, but actual renal function is preserved.
For darunavir/cobicistat: not recommended in patients with Cr Cl <70 m L/min due to cobicistat component. No dose adjustment required for Cr Cl ≥70 m L/min.
Child-Pugh A: No adjustment. Child-Pugh B or C: Contraindicated (darunavir metabolism may be impaired, no data for safety/efficacy).
Contraindicated in severe hepatic impairment (Child-Pugh Class C). Not recommended in moderate impairment (Child-Pugh Class B) due to lack of data. Use with caution in mild impairment (Child-Pugh Class A); no dose adjustment required.
Approved for patients weighing ≥40 kg: Darunavir 800 mg plus cobicistat 150 mg orally once daily with food. For <40 kg, alternative formulations (e.g., darunavir boosted with ritonavir) should be used.
Pediatric dosing for PREZCOBIX PED (darunavir/cobicistat) is weight-based: for body weight ≥40 kg: 800 mg/150 mg orally once daily with food. For weight 30 to <40 kg: 675 mg/150 mg orally once daily with food. For weight 15 to <30 kg: 600 mg/150 mg orally once daily with food. For weight <15 kg: not recommended.
No specific dose adjustment. Use with caution due to higher risk of comorbidities, polypharmacy, and potential renal/hepatic impairment; monitor renal function and drug interactions closely.
No specific dose adjustment for elderly patients; use standard dosing. Monitor renal function, as age-related decline may affect clearance of cobicistat component. Consider alternative regimen if Cr Cl <70 m L/min.
No FDA boxed warnings reported.
None
Hepatotoxicity: Drug-induced hepatitis has been reported; monitor liver function before and during therapy.,Severe skin reactions: Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS) have occurred; discontinue if severe rash or symptoms develop.,Risk of QT prolongation: Use with caution in patients with pre-existing conduction abnormalities or on other QT-prolonging drugs.,Sulfonamide allergy: Darunavir contains a sulfonamide moiety; use with caution in patients with known sulfonamide allergy.,Co-administration with certain drugs: Do not use with drugs highly dependent on CYP3A for clearance or that strongly induce CYP3A (e.g., rifampin).,Diabetes mellitus/hemophilia: May exacerbate existing conditions; monitor accordingly.
Hepatotoxicity: monitor hepatic function; discontinue if signs of hepatitis or elevated transaminases with rash or systemic symptoms occur,Severe skin reactions: including Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS); discontinue if severe rash develops,Sulfonamide allergy: darunavir contains a sulfonamide moiety; use with caution in patients with known sulfonamide allergy,Drug interactions: cobicistat is a CYP3A inhibitor; contraindicated with drugs highly dependent on CYP3A for clearance,Diabetes mellitus: new onset or exacerbation may occur,Hemophilia: increased bleeding risk in patients with hemophilia A or B,Fat redistribution and immune reconstitution syndrome
Concomitant use with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events (e.g., alfuzosin, dihydroergotamine, ergotamine, methylergonovine, cisapride, pimozide, oral midazolam, triazolam, lovastatin, simvastatin, sildenafil for pulmonary arterial hypertension, or St. John's wort).,Concomitant use with drugs that strongly induce CYP3A (e.g., rifampin) due to risk of loss of virologic response.,Patients with severe hepatic impairment (Child-Pugh Class C).
Hypersensitivity to darunavir, cobicistat, or any component of the formulation,Co-administration with drugs highly dependent on CYP3A for clearance (e.g., alfuzosin, amiodarone, colchicine in renal/hepatic impairment, ergot derivatives, lomitapide, lovastatin, oral midazolam, sildenafil for pulmonary arterial hypertension, simvastatin, triazolam),Co-administration with St. John's Wort,Severe hepatic impairment (Child-Pugh Class C)
Take with food to increase absorption. Avoid grapefruit juice as it may increase drug levels. No other specific food restrictions.
Administer with food to enhance absorption. No specific dietary restrictions, but avoid grapefruit juice as it may alter drug levels. Do not take with St. John's wort (herbal supplement). Avoid alcohol in patients with liver disease.
First trimester: Limited human data; animal studies show no teratogenicity at clinically relevant exposures. Second and third trimesters: No evidence of fetal harm; however, use only if clearly needed.
PREZCOBIX PED (darunavir/cobicistat) is contraindicated in pregnancy due to the risk of preterm delivery, low birth weight, and potential for neural tube defects based on animal studies. First trimester exposure associated with increased risk of congenital anomalies; second and third trimester exposure linked to fetal growth restriction and metabolic disturbances.
Unknown if excreted in human milk; M/P ratio not determined. Due to potential for HIV transmission and adverse effects, breastfeeding is not recommended.
Breastfeeding is not recommended for HIV-infected mothers to avoid HIV transmission. Darunavir is excreted in human milk at low concentrations; cobicistat is likely excreted. M/P ratio not established.
No dose adjustment required for standard pregnancy. Pharmacokinetic changes (e.g., increased clearance) may occur, but clinical significance not established; standard dosing maintained.
No dose adjustment required based on pharmacokinetic studies; however, consider increased monitoring for virologic failure due to potential altered drug levels. Avoid use in pregnancy if alternatives exist.
PREZCOBIX is a fixed-dose combination of darunavir (800 mg) and cobicistat (150 mg). Cobicistat is a potent CYP3A4 inhibitor; therefore, contraindicated with drugs highly dependent on CYP3A4 clearance. Darunavir requires boosting; cobicistat serves as pharmacoenhancer. No dose adjustment needed for mild-to-moderate hepatic impairment; contraindicated in severe hepatic impairment. Monitor for hepatotoxicity, especially in patients with hepatitis B or C coinfection. Cobicistat increases serum creatinine by inhibiting tubular secretion, but does not affect renal function; e GFR decline typically 10-15 m L/min/1.73m2 within 2-4 weeks and then stabilizes. Do not use in patients requiring ritonavir-boosted darunavir if they are also on tenofovir disoproxil fumarate (more renal toxicity). Administer with food to enhance absorption.
Prezcobix PED is a fixed-dose combination of darunavir (protease inhibitor) and cobicistat (pharmacokinetic enhancer) for pediatric patients. Do not use in patients with severe hepatic impairment (Child-Pugh Class C). Monitor for hepatotoxicity, especially in patients with HBV/HCV coinfection. Renal impairment: cobicistat decreases creatinine secretion, leading to increased serum creatinine without affecting GFR; no dose adjustment needed but monitor renal function. Contraindicated with drugs that are strong CYP3A inducers (e.g., rifampin, St. John's wort) or substrates with narrow therapeutic index (e.g., alfuzosin, ergot derivatives). Administer with food to enhance absorption.
Take PREZCOBIX with food, as food improves absorption.,Do not skip doses; missing doses can lead to drug resistance.,Inform your doctor of all other medications, including over-the-counter drugs, as serious interactions can occur.,Do not take with St. John's wort, certain seizure medications, or certain statins.,PREZCOBIX may increase creatinine levels in blood tests, but this does not mean your kidneys are damaged.,Report any signs of liver problems: yellowing of skin or eyes, dark urine, pale stools, abdominal pain, nausea, vomiting.,Use effective contraception as this drug may reduce effectiveness of hormonal contraceptives (except progestin-only injections).
Take exactly as prescribed; do not skip doses to reduce risk of resistance.,Must be taken with food to ensure adequate absorption.,Inform your doctor of all medications, including over-the-counter drugs and herbal supplements, due to potential interactions.,This medicine does not cure HIV; it reduces viral load and can still transmit HIV to others. Use condoms and avoid sharing needles.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, right upper quadrant pain, or unusual fatigue.,Do not use with St. John's wort, rifampin, or certain other drugs; ensure your doctor knows your full medication list.,If you have hemophilia, note that protease inhibitors may increase bleeding risk.,Store at room temperature, away from moisture and heat.
No interactions on record
No interactions on record
Common clinical questions about PREZCOBIX vs PREZCOBIX PED, answered by our medical review team.
PREZCOBIX is a HIV Antiviral (Protease Inhibitor Combination) that works by PREZCOBIX is a fixed-dose combination of darunavir, a HIV-1 protease inhibitor, and cobicistat, a CYP3A inhibitor. Darunavir selectively inhibits the cleavage of HIV-encoded Gag-Pol polyproteins in infected cells, preventing the formation of mature infectious virions. Cobicistat increases systemic exposure of darunavir by inhibiting CYP3A-mediated metabolism.. PREZCOBIX PED is a HIV Antiviral (Protease Inhibitor Combination) that works by Darumavir is an HIV-1 protease inhibitor that inhibits the cleavage of HIV-1 Gag-Pol polyproteins, resulting in non-infectious immature viral particles. Cobicistat is a CYP3A inhibitor that boosts darunavir exposure without contributing to antiviral activity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between PREZCOBIX and PREZCOBIX PED depend on the specific clinical indication. These are both HIV Antiviral (Protease Inhibitor Combination) agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of PREZCOBIX is: Darunavir 800 mg (as two 400 mg tablets) plus cobicistat 150 mg (as one 150 mg tablet) orally once daily with food.. The standard adult dose of PREZCOBIX PED is: PREZCOBIX PED is a pediatric formulation; adult dosing is not applicable. For adults, the equivalent product is PREZCOBIX (darunavir/cobicistat) fixed-dose combination: 800 mg/150 mg orally once daily with food.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between PREZCOBIX and PREZCOBIX PED in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. PREZCOBIX is classified as Category C. First trimester: Limited human data; animal studies show no teratogenicity at clinically relevant exposures. Second and third trimesters: No evidence of fetal harm; however, use on. PREZCOBIX PED is classified as Category C. PREZCOBIX PED (darunavir/cobicistat) is contraindicated in pregnancy due to the risk of preterm delivery, low birth weight, and potential for neural tube defects based on animal st. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.