erdafitinib

Contraindicated in:

OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

CYP2C9 poor metabolizers (↑ risk of adverse reactions);
Severe hepatic impairment;
Severe renal impairment;
Rep: Women of reproductive potential and men with female partners of reproductive potential;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: vascular calcification

Derm: alopecia, dry skin, nail detachment, nail discoloration, cutaneous calcinosis, palmar-plantar erythrodysesthesia syndrome

EENT: blurred vision, central serous retinopathy/retinal pigment epithelial detachment, conjunctivitis, dry eyes, lacrimation

Endo: hypoglycemia

F and E: hypercalcemia, hyperkalemia, hyperphosphatemia, hypomagnesemia, hyponatremia, hypophosphatemia

GI: abdominal pain, ↓albumin, constipation, diarrhea, dry mouth, ↑liver enzymes, metallic taste, nausea, stomatitis, vomiting

GU: hematuria, ↑serum creatinine, ↓fertility (females)

Hemat: anemia, leukopenia, neutropenia, thrombocytopenia

MS: arthralgia, pain

Metab: ↓appetite, ↓weight

Neuro: fatigue

Resp: dyspnea

Misc: fever, nonuremic calciphylaxis

Interactions ⬆ ⬇

Drug-drug:

Moderate CYP2C9 inhibitors, including fluconazole, and strong CYP3A4 inhibitors, including itraconazole, may ↑ levels and risk of toxicity; avoid concurrent use; if concurrent use unavoidable, ↓ erdafitinib dose.
Strong CYP3A4 inducers, including rifampin, may ↓ levels and effectiveness; avoid concurrent use.
Moderate CYP3A4 inducers may ↓ levels and effectiveness; avoid concurrent use; if concurrent use unavoidable, ↑ erdafitinib dose.Serum-phosphate level altering drugs may ↑ or ↓ phosphate levels, which can have impact on ability to adjust erdafitinib doses; avoid concurrent use before initial erdafitinib dose increase period.
May ↑ or ↓ levels of CYP3A4 substrates; avoid concurrent use with CYP3A4 substrates that have a narrow therapeutic index.
May ↑ levels of P-glycoprotein substrates; avoid concurrent use; if concurrent use unavoidable, separate by ≥6 hr.

Availability ⬆ ⬇

Tablets: 3 mg; 4 mg; 5 mg

Route/Dosage ⬆ ⬇

PO (Adults ): 8 mg once daily; may ↑ to 9 mg once daily at 14–21 days if serum phosphate level <9 mg/dL, no ocular disorders, and no Grade 2 or higher adverse reactions. Continue until disease progression or unacceptable toxicity. Concurrent use of moderate CYP3A4 inducers—9 mg once daily; continue until disease progression or unacceptable toxicity.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

FGFR kinase inhibitor that binds to and inhibits FGFR1, FGFR2, FGFR3, and FGFR4 enzyme activity, which results in decreased FGFR-related signaling and decreased cell viability in cell lines expressing FGFR genetic alterations, including point mutations, amplifications, and fusions.

Therapeutic effects:

Decreased spread of urothelial carcinoma.

Classifications ⬆ ⬇

Therapeutic Classification: antineoplastics

Pharmacologic Classification: kinase inhibitors, fibroblast growth factor receptor inhibitor

Pharmacokinetics ⬆ ⬇

Absorption: Unknown.

Distribution: Widely distributed to tissues.

Protein Binding: >99%.

Metabolism/Excretion: Primarily metabolized in liver by the CYP2C9 and CYP3A4 isoenzymes; the CYP2C9 isoenzyme exhibits genetic polymorphism (intermediate or poor metabolizers may have significantly ↑ erdafitinib concentrations and an ↑ risk of adverse reactions).69% excreted in feces (19% as unchanged drug), 19% in urine (13% as unchanged drug).

Half-Life: 59 hr.

Time/Action Profile ⬆ ⬇

(plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	2–6 hr	24 hr

Patient/Family Teaching ⬆ ⬇

Instruct patient to take erdafitinib as directed. If vomiting occurs any time after taking, take next dose the next day as scheduled. Take missed doses as soon as remembered on the same day. Resume regular schedule next day; do not double doses. Advise patient to read Patient Information before starting and with Rx refill in case of changes.
Advise patient to notify health care professional immediately if eye problems (dry or inflamed eyes, blurred vision, loss of vision or other visual changes). Instruct patient to use artificial tear substitutes, hydrating or lubricating eye gels or ointments at least every 2 hr during waking hours to help prevent dry eyes.
Advise patient to notify health care professional promptly if nail or skin problems (nails separating from nail bed, nail pain, nail bleeding, breaking of nails, color or texture changes in nails, infected skin around nail, itchy skin rash, dry skin, cracks in skin) occur.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: May cause fetal harm. Advise females of reproductive potential and males with female partners of reproductive potential to use effective contraception and avoid breastfeeding during and for 1 mo after last dose. May impair fertility in females of reproductive potential.
Emphasize the importance of routine lab tests and eye exams.

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Indications ⬇

Contraind./Precautions ⬆ ⬇