Cilostazole
Contraindicated
Textbook
Increased plasma levels and toxicity of cilostazole.
Should not be administered along with inhibitors of CYP3A4.
Source: KDT 7e · p555
Drug reference
Cobicistat
Pharmacokinetic enhancer (CYP3A inhibitor, no antiviral activity) · Antiretroviral Booster
START
150 mg PO once daily with food (with boosted ARV)
TYPICAL MAX
150 mg/day
STOP IF
Serious interacting-drug toxicity or true renal decline
WATCH
Full interaction review; baseline/periodic creatinine (interpret eGFR shift)
CDSCO approvedSchedule HATC V03AX03
KDIGO 2024 + manufacturer label
- ONSET
- 1h · absorption
- PEAK
- 3.5h · Tmax
- t½
- 3.5h · t½
- DURATION
- 1d · once-daily
EXCRETION
Mainly faecal; minor renal
route + CYP
INTERACTIONS
12 major
incl. contraindicated
PREGNANCY
Boosted regimens may give inadequate levels in pregnancy — alternative regimens often preferred.
FDA category + note
Top interactionssee all 12 →
- CilostazoleContraindicatedTextbookKDT 7e · p555
- AlfuzosinContraindicatedDatabaseKimi deep-research + Cla
- Ergot AlkaloidsContraindicatedDatabaseKimi deep-research + Cla
- SimvastatinContraindicatedDatabaseKimi deep-research + Cla
Mechanism
Potent mechanism-based inhibitor of CYP3A (and weak CYP2D6); has no antiviral activity itself but boosts plasma levels of co-administered CYP3A-metabolised antiretrovirals (elvitegravir, atazanavir, darunavir).
Indications
Pharmacokinetic booster for selected HIV antiretrovirals (elvitegravir, atazanavir, darunavir)
Dosing
- Adult
- 150 mg PO once daily with food, co-administered with the boosted antiretroviral (fixed-dose combinations common).
- Pediatric
- Per weight-banded fixed-dose combination products (specialist).
- Renal adjustment
- Inhibits tubular creatinine secretion (apparent eGFR fall ~10 mL/min, non-progressive); avoid starting certain TDF combos if CrCl <70.
- Hepatic adjustment
- Severe hepatic impairment: not recommended.
- Geriatric
- No specific adjustment.
- Max dose
- 150 mg/day
Pharmacokinetics
Onset
CYP3A inhibition within hours
Peak effect
~3–4 h (Tmax)
Duration
~24 h (once-daily)
Half-life
~3–4 h
Bioavailability
Enhanced with food
Protein binding
~97–98%
Metabolism
CYP3A (and CYP2D6) — substrate and inhibitor
Excretion
Mainly faecal; minor renal
Contraindications
- Co-administration with drugs highly CYP3A-dependent with serious/life-threatening toxicity (e.g., certain ergot alkaloids, lovastatin/simvastatin, some sedatives, alfuzosin)
- Hypersensitivity
Side effects
Common
NauseaDiarrhoeaHeadacheReduced estimated GFR (creatinine secretion inhibition, non-pathologic)
Serious
- Serious interactions via CYP3A inhibition
- True nephrotoxicity (with tenofovir DF combinations)
- Severe hypersensitivity
Pregnancy & lactation
Pregnancy
Boosted regimens may give inadequate levels in pregnancy — alternative regimens often preferred.
Lactation
Breastfeeding not recommended in HIV (per regional guidance).
Drug interactions
Alfuzosin
Contraindicated
Database
Increased levels
Contraindicated per label
Source: Kimi deep-research + Cla
Ergot Alkaloids
Contraindicated
Database
CYP3A inhibition
Contraindicated
Source: Kimi deep-research + Cla
Simvastatin
Contraindicated
Database
CYP3A inhibition
Contraindicated; use pravastatin/low-dose alternative
Source: Kimi deep-research + Cla
Ebastine
Severe
Textbook
Increased risk of arrhythmogenic potential.
Exercise caution with coadministration.
Source: KDT 7e
Abemaciclib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Acalabrutinib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Alfentanil
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Amiodarone
Severe
Database
Increase amiodarone levels.
Source: DDInter
Apalutamide
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Apixaban
Severe
Database
Drug interaction classified as: absorption, metabolism
Source: DDInter
Artemether
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Related guidelines
Ask House about Cobicistat
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: BNF·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20