What the label lists and what reports show
Cobicistat side effects
Cobicistat's FDA label: “The most common adverse drug reactions observed with TYBOST in combination with atazanavir (incidence greater than 5%, Grades 2−4) are jaundice and rash.” FAERS holds 618 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is cushing^s syndrome (60 reports).
- No generic listed
- A presentation discontinued
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of TYBOST?TYBOST may cause serious side effects, including: Kidney problems. TYBOST when taken with certain other medicines can cause new or worse kidney problems, including kidney failure. Your healthcare provider should do blood and urine tests to check your kidneys before you start and during treatment with TYBOST. The most common side effects of TYBOST with atazanavir include: yellowing of the skin or the whites of your eyes and rash. These are not all the possible side effects of TYBOST. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Source: FDA drug label, Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse drug reactions observed with TYBOST in combination with atazanavir (incidence greater than 5%, Grades 2−4) are jaundice and rash.
Table 4 Selected Adverse Reactions Frequencies of adverse reactions are based on Grades 2–4 adverse events attributed to study drugs. (Grades 2−4) Reported in ≥2% of Treatment-Naïve Adults with HIV-1 in the TYBOST…
| Reaction | TYBOST Coadministered with Atazanavir + TRUVADA N=344 | Ritonavir Coadministered with Atazanavir + TRUVADA N=348 |
|---|---|---|
| Jaundice | 6% | 3% |
| Rash Rash events include dermatitis allergic, drug hypersensitivity, pruritus… | 5% | 4% |
| Ocular icterus | 4% | 2% |
| Nausea | 2% | 2% |
| Diarrhea | 2% | 1% |
| Headache | 2% | 1% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe 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%). …
Source: FDA drug label, Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), via openFDA; the full label on DailyMed
What do FAERS reports show?
618 reports list cobicistat among the medicines taken, each a report of something that happened, not proof the medicine caused it; 64 are coded as a death and 192 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 19 reactions below, 2 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Cobicistat: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions