Drug reference

Posaconazole

Triazole antifungal (broad-spectrum) · Systemic Antifungal

Also known as NOXAFIL

START

DR tablet 300 mg BID day 1, then 300 mg once daily

TYPICAL MAX

300 mg/day maintenance

STOP IF

QTc >500 ms, significant hepatotoxicity, or contraindicated co-drug

WATCH

LFTs, ECG/electrolytes (K/Mg), BP; many CYP3A4 interactions

CDSCO approvedSchedule HATC J02AC04

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 2h · absorption
PEAK: 4.5h · Tmax
t½: 1.3d · t½
DURATION: 1d · once-daily

EXCRETION

Mainly faecal; minor renal

route + CYP

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

Avoid unless benefit outweighs risk (animal teratogenicity).

FDA category + note

Top interactionssee all 12 →

CilostazoleContraindicatedTextbookKDT 7e · p555
PimozideContraindicatedDatabaseKimi deep-research + Cla
SimvastatinContraindicatedDatabaseKimi deep-research + Cla
SirolimusContraindicatedDatabaseKimi deep-research + Cla

Mechanism

Inhibits fungal CYP51 (lanosterol 14-alpha-demethylase), blocking ergosterol synthesis; broad activity including Aspergillus, Candida and Mucorales.

Indications

Prophylaxis of invasive aspergillosis/candidiasis (immunocompromised)Oropharyngeal candidiasisInvasive aspergillosis (salvage)Mucormycosis (salvage)

Dosing

Adult: Delayed-release tablet 300 mg PO twice daily day 1, then 300 mg once daily. IV 300 mg twice daily day 1, then 300 mg daily. Oral suspension 200 mg three times daily (prophylaxis).
Pediatric: ≥2 y / ≥13 y per formulation and weight (specialist).
Renal adjustment: Oral: no adjustment. IV: avoid if CrCl <50 (cyclodextrin accumulation) unless benefit outweighs risk.
Hepatic adjustment: No specific adjustment; monitor LFTs.
Geriatric: No specific adjustment.
Max dose: 300 mg/day maintenance (DR tablet/IV)

Pharmacokinetics

Onset

Antifungal effect over days

Peak effect

~4–5 h (Tmax, DR tablet)

Duration

~24 h (once-daily)

Half-life

~26–35 h

Bioavailability

DR tablet/IV high; suspension food-dependent and erratic

Protein binding

>98%

Metabolism

UGT1A4 glucuronidation; CYP3A4 inhibitor (potent)

Excretion

Mainly faecal; minor renal

Contraindications

Co-administration with sirolimus, ergot alkaloids, CYP3A4-metabolised QT drugs (pimozide, quinidine), or HMG-CoA reductase inhibitors metabolised by CYP3A4 (lovastatin/simvastatin)
Hypersensitivity to azoles

Side effects

Common

Nausea/vomitingDiarrhoeaHeadacheHypokalaemiaElevated liver enzymesFever

Serious

Hepatotoxicity
QT prolongation/torsades
Severe hypersensitivity
Pseudoaldosteronism/hypertension (high exposure)

Pregnancy & lactation

Pregnancy

Avoid unless benefit outweighs risk (animal teratogenicity).

Lactation

Avoid breastfeeding (limited data).

Drug interactions

Cilostazole

Contraindicated

Textbook

Increased plasma levels and toxicity of cilostazole.

Should not be administered along with inhibitors of CYP3A4.

Source: KDT 7e · p555

Pimozide

Contraindicated

Database

Increased levels + additive QT

Contraindicated

Source: Kimi deep-research + Cla

Simvastatin

Contraindicated

Database

Potent CYP3A4 inhibition

Contraindicated; use non-CYP3A4 statin

Source: Kimi deep-research + Cla

Sirolimus

Contraindicated

Database

Markedly increased sirolimus levels

Contraindicated per label

Source: Kimi deep-research + Cla

Ebastine

Severe

Textbook

Increased risk of arrhythmogenic potential.

Exercise caution with coadministration.

Source: KDT 7e

P450 Related Drugs

Severe

Textbook

Significant drug interactions.

Source: Harrison 22e · p1692

Abemaciclib

Severe

Database