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Tucatinib Dosage

Medically reviewed by Drugs.com. Last updated on May 14, 2020.

Applies to the following strengths: 50 mg; 150 mg

Usual Adult Dose for Breast Cancer

300 mg orally 2 times a day in combination with trastuzumab and capecitabine until disease progression or unacceptable toxicity

Comments:
-When given in combination with this drug, the recommended dose of capecitabine is 1000 mg/m2 orally 2 times daily taken within 30 minutes after a meal.

Use: This drug, in combination with trastuzumab and capecitabine, is indicated for treatment of adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting

Renal Dose Adjustments

Mild to moderate renal impairment (CrCl 30 to 89 mL/min): No adjustment recommended.
Severe renal impairment (CrCl less than 30 mL/min): Use of this drug in combination with capecitabine and trastuzumab is not recommended.

Liver Dose Adjustments

Mild (Child-Pugh A) or moderate (Child-Pugh B) hepatic impairment: No adjustment recommended.
Severe (Child-Pugh C) hepatic impairment: Reduce dose to 200 mg orally 2 times daily.

Dose Adjustments

Refer to the full prescribing information for trastuzumab and capecitabine for information about dose modifications.

RECOMMENDED DOSE REDUCTION STEPS:
-First dose reduction: 250 mg orally 2 times daily
-Second dose reduction: 200 mg orally 2 times daily
-Third dose reduction: 150 mg orally 2 times daily
-Permanently discontinue this drug in patients unable to tolerate 150 mg orally 2 times daily.

DOSE MODIFICATIONS FOR ADVERSE REACTIONS:
DIARRHEA:
-Grade 3 without antidiarrheal treatment: Initiate or intensify medical management; withhold this drug until recovery to Grade 1 or less; resume at the same dose level.
-Grade 3 with antidiarrheal treatment: Initiate or intensify medical management; withhold this drug until recovery to Grade 1 or less; resume at the next lower dose level.
-Grade 4: Permanently discontinue therapy.
HEPATOTOXICITY:
-Grade 2 bilirubin (greater than 1.5 to 3 times upper limit of normal [ULN]): Withhold therapy until recovery to Grade 1 or less; resume at the same dose level.
-Grade 3 ALT or AST (greater than 5 to 20 x ULN) OR Grade 3 bilirubin (greater than 3 to 10 x ULN): Withhold therapy until recovery to Grade 1 or less; resume at the next lower dose level.
-Grade 4 ALT or AST (greater than 20 x ULN) OR Grade 4 bilirubin (greater than `10 x ULN): Permanently discontinue therapy.
-ALT or AST greater than 3 x ULN AND Bilirubin greater than 2 x ULN: Permanently discontinue therapy.
OTHER ADVERSE REACTIONS:
-Grade 3: Withhold therapy until recovery to Grade 1 or less; resume at the next lower dose level.
-Grade 4: Permanently discontinue therapy.

DOSE MODIFICATIONS FOR CONCOMITANT USE WITH STRONG CYP450 2C8 INHIBITORS:
-Avoid concomitant use of strong CYP450 2C8 inhibitors with this drug.
-If concomitant use with a strong CYP450 2C8 inhibitor cannot be avoided, reduce the dose of this drug to 100 mg orally 2 times daily.
-After discontinuation of the strong CYP450 2C8 inhibitor for 3 elimination half-lives, resume the dose of this drug that was taken prior to initiating the inhibitor.

Precautions

US BOXED WARNINGS:
NEUTROPENIA:
-Severe neutropenia may occur.
Recommendations
-Withhold therapy for absolute neutrophil count below 1500/mm3 or neutropenic fever.
-Monitor blood cell counts periodically during therapy.
-Consider G-CSF for secondary prophylaxis.
-Initiate anti-infectives in patients with febrile neutropenia.
DIARRHEA:
-Severe diarrhea may occur.
Recommendations:
-Monitor patients with diarrhea and give fluid and electrolytes as needed.
-Administer atropine, if not contraindicated, for early diarrhea of any severity.
-At the onset of late diarrhea, evaluate for infectious causes and, if negative, initiate loperamide.
-If severe diarrhea occurs, withhold therapy until resolved to less than Grade 1 and reduce subsequent doses.

CONTRAINDICATIONS:
-Hypersensitivity to the active component or any of the ingredients

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:
-Swallow tablets whole; do not chew, crush, or split prior to swallowing.
-Do not ingest tablet if it is broken, cracked, or not otherwise intact.
-Take this drug approximately 12 hours apart and at the same time each day with or without a meal.
-If the patient vomits or misses a dose, take the next dose at its usual scheduled time.

Storage requirements:
-Store at controlled room temperature, 20C to 25C (68F to 77F); excursions permitted from 15C to 30C (59F to 86F).

General:
-Dispense to patient in original container only; store in original container to protect from moisture.
-Replace cap securely each time after opening.
-Do not discard desiccant.
-Discard any unused tablets 3 months after opening the bottle.

Monitoring:
-Liver function

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.