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tybost

Pharmaranks rates Tybost 3.5/5 for recall safety — an independent score from its FDA recall history and its manufacturer's record. Tybost (Cobicistat) is a cytochrome p450 3a inhibitor used to treat Hiv Infections.

Cobicistat · by Gilead Sciences Inc

70/100Limited · 1 source

Based on 1 source · Recall-safety score from FDA recall history — this product's own recalls and its manufacturer's record. Not an efficacy or quality rating. methodology →

Rated against independent regulatory sources·Last updated August 18, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass

Key facts

Active ingredient
Cobicistat
Form
Tablet
Strength
Cobicistat 150MG · Cobicistat 90MG
Type
Prescription (Rx)
Brand or generic
Brand-name
FDA application
NDA203094
Availability
Discontinued (per FDA)

What is Tybost?

From the FDA label:TYBOST (cobicistat) is a mechanism-based CYP3A inhibitor. The chemical name for cobicistat is 1,3-thiazol-5-ylmethyl [(2 R ,5 R )-5-{[(2 S )-2-[(methyl{[2-(propan-2-yl)-1,3-thiazol-4-yl]methyl}carbamoyl)amino]-4-(morpholin-4-yl)butanoyl]amino}-1,6-diphenylhexan-2-yl]carbamate. It has a molecular formula of C 40 H 53 N 7 O 5 S 2 and a molecular weight of 776.0. It has the following structural formula: Cobicistat is adsorbed onto silicon dioxide. Cobicistat on silicon dioxide is a white to pale yellow solid with a solubility of 0.1 mg/mL in water at 20 °C. TYBOST tablets are for oral administration. Each tablet contains 150 mg or 90 mg of cobicistat. The 150 mg and 90 mg tablets include the following inactive ingredients: silicon dioxide, microcrystalline cellulose, croscarmellose sodium, and magnesium stearate. The 150 mg tablets are film-coated with a coating material containing the following inactive ingredients: polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide, sunset yellow FCF (FD&C Yellow #6) aluminum lake, and iron oxide yellow. The 90 mg tablets are film-coated with a coating material containing the following inactive ingredients: polyvinyl alcohol, titanium dioxide, polyethylene glycol, and talc. Chemical Structure

How to use

TYBOST must be coadministered with atazanavir or darunavir at the same time, with food, and in combination with other HIV-1 antiretroviral agents. ( 2.1 , 2.2 ) Recommended dosage in adults: ( 2.1 ) Adult Patient Populations Coadministered Agent Dosage TYBOST Dosage Treatment-naïve or treatment-experienced atazanavir 300 mg orally once daily 150 mg orally once daily Treatment-naïve or treatment-experienced with no darunavir resistance-associated substitutions darunavir 800 mg orally once daily Recommended dosage in pediatric patients: TYBOST 150 mg or TYBOST 90 mg orally once daily based on body weight. For dosage recommendations for TYBOST and the coadministered protease inhibitor atazanavir or darunavir in pediatric patients, refer to Table 2 and Table 3 of the full prescribing information respectively. ( 2.2 ) Prior to starting TYBOST, assess estimated creatinine clearance. ( 2.3 ) Coadministration with tenofovir disoproxil fumarate (TDF): assess estimated creatinine clearance, urine glucose, and urine protein at baseline. ( 2.3 ) TYBOST coadministered with TDF is not recommended in patients who have an estimated creatinine clearance below 70 mL/min because dose adjustment of TDF is required below 50 mL/min and such dose adjustments have not been established for coadministration with TYBOST. ( 2.4 ) 2.1 Recommended Dosage in Adults Administer TYBOST in conjunction with…

Side effects

The following adverse reaction is described in greater detail in another section of the labeling: New Onset or Worsening Renal Impairment When Used with Tenofovir Disoproxil Fumarate [see Warnings and Precautions (5.2) ]. The most common adverse drug reactions observed with TYBOST in combination with atazanavir (incidence greater than 5%, Grades 2−4) are jaundice and rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Gilead Sciences, Inc. at 1-800-GILEAD-5 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adverse Reactions from Clinical Trials Experience in Adults The safety of TYBOST is based on Week 144 data from a Phase 3 trial, Trial 114, in which 692 antiretroviral treatment-naïve participants with HIV-1 received: TYBOST coadministered with atazanavir and TDF/emtricitabine (administered as TRUVADA) (N=344) or ritonavir coadministered with atazanavir and TDF/emtricitabine (administered as TRUVADA) (N=348). The most common adverse reactions (Grades 2−4) and reported in >5% of participants in the TYBOST group were jaundice (6%) and rash (5%). The proportion of participants…

Warnings

Important safety information

Assess creatinine clearance (CLcr) before initiating treatment. ( 5.1 ) When TYBOST is used in combination with a TDF-containing regimen, cases of acute renal failure and Fanconi syndrome have been reported. ( 5.2 ) Use with TDF: Assess urine glucose and urine protein at baseline and monitor CLcr, urine glucose, and urine protein. Monitor serum phosphorus in patients with or at risk for renal impairment. ( 5.2 ) TYBOST in combination with more than one antiretroviral that requires pharmacokinetic enhancement (i.e., two protease inhibitors or elvitegravir in combination with a protease inhibitor) is not recommended. ( 5.4 ) Use with HIV-1 protease inhibitors other than atazanavir or darunavir administered once daily is not recommended. ( 5.4 ) Coadministration with drugs or regimens containing ritonavir is not recommended. ( 5.4 ) 5.1 Effects on Serum Creatinine TYBOST decreases estimated creatinine clearance due to inhibition of tubular secretion of creatinine without affecting actual renal glomerular function. This effect should be considered when interpreting changes in estimated creatinine clearance in patients initiating TYBOST, particularly in patients with medical conditions or receiving drugs needing monitoring with estimated creatinine clearance. Prior to initiating therapy with TYBOST, assess estimated creatinine clearance [see Dosage and Administration (2.3) ] . Dosage recommendations are not available for drugs that require dosage adjustments in TYBOST-treated patients with renal impairment [see Adverse Reactions (6.1) , Drug Interactions (7.3) , and Clinical Pharmacology (12.2) ] . Consider alternative medications that do not require dosage adjustments in patients with renal impairment. Although TYBOST may cause modest increases in serum creatinine and modest declines in estimated creatinine clearance without affecting renal glomerular function, patients who experience a confirmed increase in serum creatinine of greater than 0.4 mg/dL from baseline should be closely monitored for renal safety. 5.2 New Onset or Worsening Renal Impairment When Used with Tenofovir Disoproxil Fumarate Renal impairment, including cases of acute renal failure and Fanconi syndrome, has been reported when TYBOST was used in an antiretroviral regimen that contained TDF. Coadministration of TYBOST and TDF is not recommended in patients who have an estimated creatinine clearance below 70 mL/min because dose adjustment of TDF is required below 50 mL/min and such dose adjustments have not been established for coadministration with TYBOST [see Dosage and Administration (2.3 , 2.4) ] . Document urine glucose and urine protein at baseline [see Dosage and Administration (2.3) ] and perform routine monitoring of estimated creatinine clearance, urine glucose, and urine protein during treatment when TYBOST is used with TDF. Measure serum phosphorus in patients with or at risk for renal impairment when used with TDF. Coadministration of TYBOST and TDF in combination with concomitant or recent use of a nephrotoxic agent is not recommended. In a clinical trial of TYBOST over 144 weeks (N=692), 10 (2.9%) participants treated with TYBOST coadministered with atazanavir and TRUVADA ® and 11 (3.2%) participants treated with ritonavir coadministered with atazanavir and TRUVADA discontinued study drug due to a renal adverse event. Seven of the 10 participants (2.0% overall) in the TYBOST group had laboratory findings consistent with proximal renal tubulopathy leading to study drug discontinuation compared to 7 of 11 participants (2.0% overall) in the ritonavir group. One participant in the TYBOST group had renal impairment at baseline (i.e., estimated creatinine clearance less than 70 mL/min). The laboratory findings in these 7 participants with evidence of proximal tubulopathy improved but did not completely resolve in all participants upon discontinuation of TYBOST coadministered with atazanavir and TRUVADA. Renal replacement therapy was not required in any participant. 5.3 Risk of Serious Adverse Reactions or Loss of Virologic Response Due to Drug Interactions Initiation of TYBOST, a CYP3A inhibitor, in patients receiving medications metabolized by CYP3A, or initiation of medications metabolized by CYP3A in patients already receiving TYBOST, may increase plasma concentrations of medications metabolized by CYP3A and reduce plasma concentrations of active metabolite(s) formed by CYP3A. Initiation of medications that inhibit or induce CYP3A may respectively increase or decrease concentrations of TYBOST with atazanavir or darunavir. These interactions may lead to: clinically significant adverse reactions, potentially leading to severe, life-threatening, or fatal events from higher exposures of concomitant medications. clinically significant adverse reactions from higher exposures of TYBOST and atazanavir or darunavir. These interactions may lead to: loss of therapeutic effect of TYBOST with atazanavir or darunavir and possible development of resistance. loss of therapeutic effect of the concomitant medications from lower exposures of active metabolite(s). See Table 7 for steps to prevent or manage these possible and known significant drug interactions, including dosing recommendations [see Drug Interactions (7) ] . Consider the potential for drug interactions prior to and during TYBOST with atazanavir or darunavir therapy; review concomitant medications during TYBOST with atazanavir or darunavir therapy; and monitor for the adverse reactions associated with concomitant medications [see Contraindications (4) and Drug Interactions (7) ] . TYBOST or ritonavir when administered with either atazanavir or darunavir may result in different drug interactions when used with concomitant medications. Complex or unknown mechanisms of drug interactions preclude extrapolation of ritonavir drug interactions to certain TYBOST interactions [see Drug Interactions (7) and Clinical Pharmacology (12.3) ]. 5.4 Antiretrovirals that are Not Recommended in Combination with TYBOST The following antiretrovirals are not recommended in combination with TYBOST because dosing recommendations for such combinations have not been established and coadministration may result in decreased plasma concentrations of the antiretroviral agents, leading to loss of therapeutic effect and development of resistance: More than one antiretroviral that requires pharmacokinetic enhancement (i.e., two protease inhibitors or a protease inhibitor in combination with elvitegravir) Darunavir in combination with efavirenz, nevirapine, or etravirine Atazanavir in combination with etravirine Atazanavir in combination with efavirenz in treatment-experienced patients Darunavir 600 mg twice daily Other HIV-1 protease inhibitors including fosamprenavir, saquinavir, or tipranavir TYBOST in combination with fixed-dose combination tablets that contain cobicistat is not recommended. TYBOST in combination with lopinavir/ritonavir or regimens containing ritonavir is not recommended due to similar effects of TYBOST and ritonavir on CYP3A.

Who should not take Tybost

The concomitant use of TYBOST with atazanavir or darunavir and the following drugs is contraindicated due to the potential for serious and/or life-threatening events or loss of therapeutic effect [see Drug Interactions (7.3) and Clinical Pharmacology (12.3) ] . Alpha 1-adrenoreceptor antagonist: alfuzosin Antianginal: ranolazine Antiarrhythmic: dronedarone Anticonvulsants: carbamazepine, phenobarbital, phenytoin Anti-gout: colchicine Antimycobacterial: rifampin Antineoplastics: irinotecan These contraindications apply only to TYBOST coadministered with atazanavir Antipsychotics: lurasidone, pimozide Ergot Derivatives: dihydroergotamine, ergotamine, methylergonovine Herbal Products: St. John's wort ( Hypericum perforatum ) Hormonal Contraceptives: drospirenone/ ethinyl estradiol Lipid-modifying Agents: lomitapide, lovastatin, simvastatin Non-nucleoside Reverse Transcriptase Inhibitor: nevirapine Phosphodiesterase-5 (PDE-5) Inhibitor: sildenafil when administered as Revatio ® for the treatment of pulmonary arterial hypertension Protease Inhibitor: indinavir Sedative/hypnotics triazolam, orally administered midazolam Coadministration with certain drugs for which altered plasma concentrations are associated with serious and/or life-threatening events or loss of therapeutic effect. ( 4 )

Overdose — what happens if you take too much

If overdose occurs, the patient must be monitored for evidence of toxicity. Treatment of overdose with TYBOST consists of general supportive measures including monitoring of vital signs, as well as observation of the clinical status of the patient. As cobicistat is highly bound to plasma proteins, it is unlikely that it will be significantly removed by hemodialysis or peritoneal dialysis.

U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.

Interactions

TYBOST, in combination with atazanavir or darunavir, can alter the concentration of drugs metabolized by CYP3A or CYP2D6. Drugs that induce CYP3A can alter the concentrations of TYBOST, atazanavir and darunavir. Consult the full prescribing information prior to and during treatment for potential drug interactions. ( 4 , 5.3 , 7 , 12.3 ) 7.1 Potential Effect of Cobicistat (Coadministered with Atazanavir or Darunavir) on the Pharmacokinetics of Concomitant Drugs Cobicistat is an inhibitor of CYP3A and CYP2D6. The transporters that cobicistat inhibits include p-glycoprotein (P-gp), BCRP, OATP1B1, and OATP1B3. The plasma concentration of drugs that are primarily metabolized by CYP3A or CYP2D6, or are substrates of P-gp, BCRP, OATP1B1, or OATP1B3 may be increased if those drugs are coadministered with TYBOST. Based on in vitro data, cobicistat is not expected to induce CYP1A2 or CYP2B6 and based on in vivo data, cobicistat is not expected to induce MDR1 or, in general, CYP3A to a clinically significant extent. The induction effect of cobicistat on CYP2C9, CYP2C19, or UGT1A1 is unknown, but is expected to be low based on CYP3A in vitro induction data. Coadministration of TYBOST with atazanavir or darunavir with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated. Coadministration with drugs that have active metabolite(s) formed by CYP3A may result in reduced plasma concentrations of these active metabolite(s). Coadministration with other CYP3A substrates may require a dose adjustment or additional monitoring as shown in Table 7 . 7.2 Potential Effect of Concomitant Drugs on the Pharmacokinetics of Cobicistat (Coadministered with Atazanavir or Darunavir) Cobicistat is metabolized by CYP3A, and to a minor extent, by CYP2D6. Atazanavir and darunavir are also metabolized by CYP3A. Coadministration of TYBOST with atazanavir or darunavir in combination with drugs that induce CYP3A activity have the potential to decrease plasma concentrations of cobicistat, atazanavir, and darunavir, which may lead to loss of therapeutic effect and development of resistance (see Table 7 ). Coadministration of TYBOST with atazanavir or darunavir in combination with other drugs that inhibit CYP3A may further increase the plasma concentrations of cobicistat, atazanavir, and darunavir (see Table 7 ). 7.3 Established and Other Potentially Significant Interactions Coadministration of TYBOST with fosamprenavir, saquinavir, or tipranavir is not recommended because pharmacokinetic data are not available to provide appropriate dosing recommendations. Use of TYBOST with lopinavir is not recommended because lopinavir is co-formulated with ritonavir. Table 7 provides dosing recommendations as a result of drug interactions with TYBOST coadministered with atazanavir or darunavir. These recommendations are based on either drug interaction trials or predicted interactions due to the expected magnitude of the interaction and potential for serious adverse events or loss of therapeutic effect [see Contraindications (4) , Warnings and Precautions (5.3 , 5.4) , and Clinical Pharmacology (12.3) ]. In Table 7 , if not specifically stated, the drug interaction information applies to both coadministered agents: TYBOST coadministered with atazanavir or darunavir [see Clinical Pharmacology (12.3) ] . In addition to the drug interactions noted in Table 7 , TYBOST is not recommended for use in combination with fixed-dose combination tablets that contain cobicistat, lopinavir/ritonavir or regimens containing ritonavir, or in combination with more than one antiretroviral agent that requires pharmacokinetic enhancement [see Warnings and Precautions (5.4) ]. Evaluate whether dosing adjustments of concomitant medications or coadministered antiretroviral drugs are necessary in: Patients on a stable concomitant medication who initiate or switch to a TYBOST-containing regimen Patients on a TYBOST-containing regimen who initiate a new concomitant medication Patients initiating a TYBOST-containing regimen and a new concomitant medication simultaneously Under these circumstances, also monitor for adverse events and/or monitor concentrations of concomitant medications if appropriate. No dose adjustment is required when TDF or rilpivirine are coadministered with TYBOST and atazanavir or darunavir. Table 7 Established and Other Potentially Significant This table is not all inclusive. Drug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Studies or Predicted Interaction Concomitant Drug Class: Drug Name Potential Effect ↑ = Increase, ↓ = Decrease, ↔ = No change Clinical Comment Antiretroviral Agents: Nucleotide Reverse Transcriptase Inhibitor (NRTI) tenofovir alafenamide ↔tenofovir alafenamide ↑tenofovir alafenamide TYBOST coadministered with darunavir in pediatric patients weighing at least 15 kg: No dose adjustment. TYBOST coadministered with atazanavir in pediatric patients weighing 14 to less than 35 kg: Coadministration is not recommended [see Use in Specific Populations (8.4) ]. Antiretroviral Agents: Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) efavirenz ↓ cobicistat ↓ darunavir ↓ atazanavir TYBOST coadministered with darunavir: Coadministration of darunavir and TYBOST with efavirenz is not recommended because it may result in the loss of therapeutic effect and development of resistance to darunavir. TYBOST coadministered with atazanavir: In treatment-naïve adult patients: Atazanavir 400 mg with TYBOST 150 mg should be coadministered once daily as a single dose with food, and efavirenz 600 mg should be administered once daily on an empty stomach, preferably at bedtime. In treatment-experienced adult patients: Coadministration of atazanavir and TYBOST with efavirenz in treatment-experienced patients is not recommended because it may result in the loss of therapeutic effect and development of resistance to atazanavir. etravirine ↓ cobicistat darunavir: effect unknown ↓ atazanavir Coadministration with etravirine is not recommended because it may result in the loss of therapeutic effect and development of resistance to atazanavir or darunavir. nevirapine ↓ atazanavir ↑ nevirapine ↓ cobicistat darunavir: effect unknown Contraindicated with TYBOST coadministered with atazanavir only: Coadministration of atazanavir with nevirapine is contraindicated due to potential for loss of atazanavir therapeutic effect and development of resistance, and potential for nevirapine-associated adverse reactions. TYBOST coadministered with darunavir: TYBOST coadministration with nevirapine and darunavir is not recommended because it may result in the loss of therapeutic effect and development of resistance to darunavir. Antiretroviral Agents: CCR5 Antagonists maraviroc ↑ maraviroc Maraviroc is a substrate of CYP3A. When coadministering with maraviroc, adult patients should receive maraviroc 150 mg twice daily. Antiretroviral Agents: Protease Inhibitors indinavir Contraindicated with TYBOST coadministered with atazanavir only: Both atazanavir and indinavir are associated with indirect (unconjugated) hyperbilirubinemia. Other Agents: Alpha 1- adrenoreceptor antagonist: alfuzosin ↑ alfuzosin Coadministration with alfuzosin is contraindicated due to potential for serious and/or life-threatening reactions such as hypotension. Antianginal ranolazine ↑ ranolazine Coadministration with ranolazine is contraindicated due to potential for serious and/or life-threatening reactions. Antacids: e.g., aluminum and magnesium hydroxide (please also see H2-Receptor Antagonists and Proton Pump Inhibitors below) ↓ atazanavir TYBOST coadministered with atazanavir: With concomitant use, administer a minimum of 2 hours apart. Antiarrhythmics: dronedarone ↑ dronedarone Coadministration with dronedarone is contraindicated due to potential for serious and/or life-threatening reactions such as cardiac arrhythmias. digoxin ↑ digoxin When coadministering with digoxin, titrate the digoxin dose and monitor digoxin concentrations. Other antiarrhythmics: e.g., amiodarone disopyramide flecainide mexiletine propafenone quinidine ↑ antiarrhythmics Clinical monitoring is recommended upon coadministration with antiarrhythmics. Antibacterials (macrolide or ketolide antibiotics): clarithromycin erythromycin telithromycin ↑ clarithromycin ↑ erythromycin ↑ telithromycin ↑ cobicistat ↑ atazanavir ↑ darunavir Consider alternative antibiotics with concomitant use of TYBOST coadministered with atazanavir or darunavir. Anticancer Agents: irinotecan ↑ irinotecan Contraindicated with TYBOST coadministered with atazanavir only: Coadministration of atazanavir with irinotecan is contraindicated due to potential for increased irinotecan toxicity. dasatinib nilotinib vinblastine vincristine ↑ anticancer agents A decrease in the dosage or an adjustment of the dosing interval of dasatinib or nilotinib may be necessary upon coadministration with TYBOST coadministered with atazanavir or darunavir. Consult the dasatinib and nilotinib prescribing information for dosing instructions. For vincristine and vinblastine, monitor for hematologic or gastrointestinal side effects. Anticoagulants: Direct Oral Anticoagulants (DOACs) apixaban rivaroxaban betrixaban dabigatran edoxaban ↑ apixaban TYBOST coadministered with atazanavir or darunavir: Due to potentially increased bleeding risk, dosing recommendations for coadministration of apixaban with TYBOST depends on the apixaban dose. Refer to apixaban dosing instructions for coadministration with strong CYP3A and P-gp inhibitors in apixaban prescribing information. ↑ rivaroxaban Coadministration of rivaroxaban with TYBOST is not recommended because it may lead to an increased bleeding risk. atazanavir: ↑ betrixaban ↑ dabigatran ↑ edoxaban TYBOST coadministered with atazanavir: Due to potentially increased bleeding risk, dosing recommendations for coadministration of betrixaban, dabigatran, or edoxaban with a P-gp inhibitor such as TYBOST coadministered with atazanavir depends on DOAC indication and renal function. Refer to DOAC dosing instructions for coadministration with P-gp inhibitors in DOAC prescribing information. darunavir: ↔ betrixaban ↔ dabigatran ↔ edoxaban TYBOST coadministered with darunavir: No dose adjustment. warfarin warfarin: effect unknown Monitor the international normalized ratio (INR) upon coadministration of TYBOST with warfarin. Anticonvulsants: carbamazepine, phenobarbital, phenytoin ↓ atazanavir ↓ darunavir ↓ cobicistat Coadministration with carbamazepine, phenobarbital, or phenytoin is contraindicated due to potential for loss of therapeutic effect and development of resistance. Anticonvulsants with CYP3A induction effects that are NOT contraindicated e.g., eslicarbazepine, oxcarbazepine ↓ cobicistat ↓ atazanavir darunavir: effect unknown Consider alternative anticonvulsant or antiretroviral therapy to avoid potential changes in exposures. If coadministration is necessary, monitor for lack or loss of virologic response. Anticonvulsants that are metabolized by CYP3A e.g., clonazepam ↑ clonazepam Clinical monitoring of anticonvulsants is recommended. Antidepressants: Selective Serotonin Reuptake Inhibitors (SSRIs) e.g., paroxetine Tricyclic Antidepressants (TCAs) e.g., amitriptyline desipramine imipramine nortriptyline Other antidepressants: trazodone SSRIs: effects unknown ↑ TCAs ↑ trazodone When coadministering with SSRIs, TCAs, or trazodone, careful dose titration of the antidepressant to the desired effect, including using the lowest feasible initial or maintenance dose, and monitoring for antidepressant response are recommended. Antifungals: itraconazole ketoconazole ↑ itraconazole ↑ ketoconazole Specific dosing recommendations are not available for coadministration with itraconazole or ketoconazole. voriconazole Voriconazole: effects unknown ↑ cobicistat ↑ atazanavir ↑ darunavir Coadministration with voriconazole is not recommended unless the benefit/risk assessment justifies the use of voriconazole. Anti-gout: colchicine ↑ colchicine Coadministration with colchicine is contraindicated in patients with renal and/or hepatic impairment due to potential for serious and/or life-threatening reactions. Treatment of gout flares in adult patients – coadministration of colchicine: 0.6 mg (1 tablet) x 1 dose, followed by 0.3 mg (half tablet) 1 hour later. Treatment course to be repeated no earlier than 3 days. Prophylaxis of gout flares in adult patients – coadministration of colchicine: If the original regimen was 0.6 mg twice a day, the regimen should be adjusted to 0.3 mg once a day. If the original regimen was 0.6 mg once a day, the regimen should be adjusted to 0.3 mg once every other day. Treatment of familial Mediterranean fever in adult patients – coadministration of colchicine: Maximum daily dose of 0.6 mg (may be given as 0.3 mg twice a day). Antimycobacterial: rifampin ↓ atazanavir ↓ darunavir ↓ cobicistat Coadministration with rifampin is contraindicated due to potential for loss of therapeutic effect and development of resistance. rifabutin ↑ rifabutin cobicistat: effects unknown darunavir: effects unknown atazanavir: effects unknown The recommended adult dosage regimen for rifabutin is 150 mg every other day. Monitor for rifabutin associated adverse reactions including neutropenia and uveitis. Antiplatelets: ticagrelor ↑ ticagrelor Coadministration with ticagrelor is not recommended. clopidogrel ↓ clopidogrel active metabolite Coadministration with clopidogrel is not recommended due to potential reduction of the antiplatelet activity of clopidogrel. prasugrel ↔ prasugrel active metabolite No dose adjustment is needed when prasugrel is co-administered with TYBOST. Antipsychotics: lurasidone ↑ lurasidone Coadministration with lurasidone is contraindicated due to potential for serious and/or life-threatening reactions. pimozide ↑ pimozide Coadministration with pimozide is contraindicated due to potential for serious and/or life-threatening reactions such as cardiac arrhythmias. quetiapine ↑ quetiapine Initiation of TYBOST coadministered with atazanavir or darunavir in patients taking quetiapine: Consider alternative antiretroviral therapy to avoid increases in quetiapine exposure. If coadministration is necessary, reduce the quetiapine dose to 1/6 of the current dose and monitor for quetiapine-associated adverse reactions. Refer to the quetiapine prescribing information for recommendations on adverse reaction monitoring. Initiation of quetiapine in patients taking TYBOST coadministered with atazanavir or darunavir: Refer to the quetiapine prescribing information for initial dosing and titration of quetiapine. Other antipsychotics: e.g., perphenazine risperidone thioridazine ↑ antipsychotic A decrease in the dose of antipsychotics that are metabolized by CYP3A or CYP2D6 may be needed upon coadministration. Beta-Blockers: e.g., metoprolol carvedilol timolol ↑ beta-blockers Clinical monitoring is recommended for coadministration with beta-blockers that are metabolized by CYP2D6. Calcium Channel Blockers: e.g., amlodipine diltiazem felodipine nifedipine verapamil ↑ calcium channel blockers Clinical monitoring is recommended for coadministration with calcium channel blockers metabolized by CYP3A. Corticosteroids: e.g., betamethasone budesonide ciclesonide dexamethasone fluticasone methylprednisolone mometasone triamcinolone ↓ cobicistat ↓ atazanavir ↓ darunavir ↑ corticosteroids Coadministration with oral dexamethasone or other systemic corticosteroids that induce CYP3A may result in loss of therapeutic effect and development of resistance to atazanavir or darunavir. Consider alternative corticosteroids. Coadministration with corticosteroids (all routes of administration) whose exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression. Alternative corticosteroids including beclomethasone, prednisone, and prednisolone (whose PK and/or PD are less affected by strong CYP3A inhibitors relative to other studied steroids) should be considered, particularly for long-term use . Endothelin Receptor Antagonists: bosentan ↑ bosentan ↓ cobicistat ↓ darunavir ↓ atazanavir Initiation of bosentan in adult patients taking TYBOST coadministered with atazanavir or darunavir: In patients who have been receiving TYBOST coadministered with atazanavir or darunavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Initiation of TYBOST coadministered with atazanavir or darunavir in adult patients taking bosentan: Discontinue use of bosentan at least 36 hours prior to initiation of TYBOST coadministered with atazanavir or darunavir. After at least 10 days following the initiation of TYBOST combined with atazanavir or darunavir, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Switching from ritonavir to TYBOST coadministered with atazanavir or darunavir: Maintain bosentan dose. Ergot Derivatives: dihydroergotamine, ergotamine, methylergonovine ↑ ergot derivatives Coadministration is contraindicated due to potential for serious and/or life-threatening reactions such as acute ergot toxicity characterized by peripheral vasospasm and ischemia of the extremities and other tissues. H 2 -Receptor Antagonists: e.g., famotidine ↓ atazanavir TYBOST coadministered with atazanavir in adult patients: Administer atazanavir/TYBOST either at the same time or a minimum of 10 hours after administering H 2 -receptor antagonists. The dose of the H 2 -receptor antagonist should not exceed a dose comparable to famotidine 40 mg twice daily in treatment-naïve adult patients or 20 mg twice daily in treatment-experienced adult patients. TYBOST coadministered with atazanavir and TDF in adult patients: Treatment-experienced adult patients: The recommended once daily dosage regimen is TYBOST 150 mg coadministered with atazanavir 400 mg with concomitant use of H 2 -receptor antagonists and tenofovir DF. Herbal Products: St. John’s wort (Hypericum perforatum) ↓ atazanavir ↓ darunavir ↓ cobicistat Coadministration is contraindicated due to potential for loss of therapeutic effect and development of resistance. Hormonal Contraceptives: Additional or alternative non-hormonal forms of contraception should be considered when estrogen based contraceptives are coadministered with TYBOST and atazanavir or darunavir. drospirenone/ethinyl estradiol atazanavir: ↑ drospirenone Contraindicated with TYBOST coadministered with atazanavir only: Coadministration of atazanavir with drospirenone is contraindicated due to potential for drospirenone-associated hyperkalemia. darunavir: ↑ drospirenone ↓ ethinyl estradiol TYBOST coadministered with darunavir: For coadministration with drospirenone, clinical monitoring is recommended due to the potential for hyperkalemia. Other progestin/estrogen contraceptives progestin: effects unknown estrogen: effects unknown No data are available to make recommendations on the coadministration of TYBOST and atazanavir or darunavir with other hormonal contraceptives. Immuno-suppressants: cyclosporine everolimus sirolimus tacrolimus ↑ immuno-suppressants These immunosuppressant agents are metabolized by CYP3A. Therapeutic drug monitoring is recommended if coadministered. Inhaled Beta Agonist: salmeterol ↑ salmeterol Coadministration with salmeterol is not recommended and may result in increased risk of cardiovascular adverse events associated with salmeterol, including QT prolongation, palpitations, and sinus tachycardia. Lipid-modifying Agents: HMG-CoA reductase inhibitors: lovastatin simvastatin ↑ lovastatin ↑ simvastatin Coadministration with lovastatin or simvastatin is contraindicated due to potential for serious reactions such as myopathy including rhabdomyolysis. Other HMG-CoA…

Drug class

May treat (source: NIH RxClass)

Dosage forms

Tablet

The forms currently marketed in the U.S., per the FDA National Drug Code Directory.

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Frequently asked questions

What does Tybost treat?
Tybost (Cobicistat) may be used to treat HIV infections, based on NIH RxClass drug-classification data (conditions a drug may treat — not a verbatim copy of the FDA-approved label). This is general reference, not medical advice.
How is Tybost rated?
pharmaranks gives Tybost a composite score of 3.5 out of 5, currently based on 1 weighted source (FDA regulatory recall-safety data weighted highest). See our methodology at /how-we-rate.
Is there a coupon or discount for Tybost?
pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Tybost. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
Who makes Tybost?
Tybost is marketed by Gilead Sciences Inc. You can see Gilead Sciences Inc's full profile, rating, and other products on pharmaranks.
Is Tybost a brand-name or generic drug?
Tybost is a brand-name product with the active ingredient Cobicistat.
Is Tybost available over the counter?
No. Tybost is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
What forms does Tybost come in?
Tybost is currently marketed as tablet, per the FDA's National Drug Code Directory.
What class of drug is Tybost?
Tybost is classified as cytochrome p450 3a inhibitor, per the FDA's Established Pharmacologic Class.
Is Tybost FDA-registered?
Tybost is on record with the U.S. FDA under application number NDA203094. You can verify this on its official FDA label.
Has Tybost been recalled by the FDA?
Tybost has no FDA recalls recorded under its own application in the openFDA enforcement database. Its recall-safety score reflects its manufacturer's overall recall record. This is general reference, not medical advice — check the FDA recall database for the latest alerts.
Is Tybost safe?
There's no single safe-or-not verdict. pharmaranks gives Tybost a recall-safety score of 70/100, based on its FDA recall history (no recalls under its own FDA application) — not an efficacy or side-effect rating. Review its FDA-label side effects and warnings before use, and always consult a licensed professional.
What are the side effects of Tybost?
Tybost's side effects are taken directly from its FDA label. From the label: The following adverse reaction is described in greater detail in another section of the labeling: New Onset or Worsening Renal Impairment When Used with Tenofovir Disoproxil Fumarate [see Warnings and Precautions (5.2) ].… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.

Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

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